Circular No. 39/2015/TT-BCT on Distribution Power Systems

CIRCULAR

Provisions on the distribution power systemANNEX I.A[31]

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Pursuant to Decree No. 95/2012/NĐ-CP dated November 12, 2012, of the Government, detailing the functions, tasks, powers, and organizational structure of the Ministry of Industry and Trade;

Pursuant to the Electricity Law dated December 3, 2004 and the Law Amending and Supplementing Certain Articles of the Electricity Law dated November 20, 2012;

Based on Decree No. 137/2013/NĐ-CP dated October 21, 2013, issued by the Government, detailing the implementation of certain provisions of the Electricity Law and the Law Amending and Supplementing Certain Provisions of the Electricity Law;

At the proposal of the Director of the Electricity Regulatory Authority,

The Minister of Industry and Trade issues Circulars to stipulate the distribution power system.

PART I

GENERAL PROVISIONS

Article 1. Scope of Regulation

This Circular stipulates on:

1. Requirements for operating the distribution power system.

2. Forecasting electricity demand.

3. Investment plan for developing the distribution power grid.

4. Conditions, technical requirements, and procedures for connecting to the distribution power grid.

5. Operation of the distribution power system.

Article 2. Applicability

This Circular applies to the following subjects:

Distribution power unit.

Distribution and retail power unit.

National power system dispatching unit.

4. Transmission electricity unit.

5. Customer using the distribution power grid.

6. Vietnam Electricity Corporation.

7. Other organizations and individuals related.

Article 3. Explanation of Terms

Strategic multi-purpose hydropower plant

1. Voltage Level is one of the nominal voltage values used in the power system, including:

a) Low voltage is up to 01 kV nominal voltage;

b) Medium voltage is above 01 kV up to 35 kV nominal voltage;

c) High voltage is above 35 kV up to 220 kV nominal voltage;

d) Extra high voltage is above 220 kV nominal voltage.

2. Dispatching level has the right to control is the dispatching level that has the authority to command and dispatch the power system according to the dispatching hierarchy..

3. Available capacity of the power generation unit is the maximum stable and continuous generating capacity of the power generation unit within a specified period.

4. Voltage fluctuation is the change in voltage amplitude compared to the nominal voltage over a time longer than 01 minute.

5. Point of Interconnection is the point where customer's equipment, grid, and power plant connect to the distribution power grid.

6. National power system dispatching unit is the unit commanding and controlling the process of power generation, transmission, and distribution in the national power system, including the following dispatching levels:

a) National-level dispatching;

b) Regional-level dispatching.

7. Power Generation Unit is a power organization owning one or more power plants connected to the distribution power grid, licensed to operate in the power generation sector.

8. is an electricity unit licensed to operate in the field of distribution and sale of electricity, including: is a power organization licensed to operate in the distribution and retail power sectors, including:

a) State Corporation of Electricity;

b) Provincial Electricity Company under the Provincial Electricity Corporation (hereinafter referred to as Provincial Electricity Company).

9. Distribution and Retail Companies is a power organization licensed to operate in the distribution and retail power sectors, purchasing bulk power from distribution power units to sell to end-users.

10. Transmission electricity unit is a power organization licensed to operate in the power transmission sector, responsible for managing and operating the national power transmission grid.

11. Grounding factor is the ratio between the value of the phase voltage without fault after a ground fault occurs and the value of that phase before the fault occurs (applicable for single-phase or double-phase ground faults).

12. Distribution power system is the power system consisting of the distribution grid and power plants connected to the distribution grid.

13. Measurement system is a system comprising measuring devices and circuits integrated to measure and determine the amount of electric energy transmitted through a metering point.

14. SCADA System (Supervisory Control And Data Acquisition) is a system collecting data to serve monitoring, controlling, and operating the power system.

15. Electricity consumer is an organization or individual purchasing electricity from the distribution power grid for use, not reselling it to other organizations or individuals.

16. Distribution grid consumer is an organization or individual with electrical equipment and grid connected to the distribution power grid to use distribution services, including:

a) Power generation unit;

b) Distribution and retail electricity unit;

c) Electricity consumer.

17. Large customers using the distribution power grid are customers using the distribution power grid, including:

a) Power generation unit owning a power plant with a capacity of 03 MW or more;

b) Customers using electricity with an average consumption of 1,000,000 kWh/month or more.

18. Customers using the distribution power grid with their own substation are customers having their own substation and grid connected to the distribution power grid at medium voltage and 110 kV levels.

19. Dispatching order is the command and control order for the operation mode of the power system in real-time.

20. Distribution Grid is the part of the grid consisting of lines and substations up to 110 kV.

21. Transmission Grid is the part of the grid consisting of lines and substations above 110 kV.

22. Typical day is the selected day with typical electricity consumption patterns of the load according to the provisions on the content, methods, procedures, and processes for studying electricity loads issued by the Ministry of Industry and Trade. A typical day includes typical working days, weekends, and holidays (if applicable) for the year, month, and week.

23. Grid separation is the failure causing disconnection between power plants and substations leading to partial or total blackout of the regional or national power system.

24. Load shedding is the process of disconnecting loads from the grid when there is a fault in the power system or short-term local overload to ensure safe operation of the power system, carried out through automatic load shedding systems or dispatching orders.

25. Harmonic wave is a sine wave voltage and current with frequency being multiples of the fundamental frequency.

26. Remote Terminal Unit/ Gateway device is a device installed at substations or power plants for collecting and transmitting data to the SCADA system's control center.

27. Disconnection is the act of disconnecting the grid or electrical equipment of customers using the distribution power grid from the distribution power grid at the connection point.

28. Connection agreement is the document agreeing between the distribution power unit and customers using the distribution power grid with their own substation to connect their electrical equipment to the distribution power grid.

29. IEC Standard is the standard on electrical technology issued by the International Electrotechnical Commission.

30. Substation is a transformer station, switch station, or compensation station.

31. Control center is a center equipped with information and communication infrastructure technology to remotely monitor and control a group of power plants, a group of substations, or switching devices on the grid.

Chapter II

REQUIREMENTS FOR OPERATING THE DISTRIBUTION POWER SYSTEM

Section 1

TECHNICAL REQUIREMENTS

Article 4. Frequency

The designated frequency in the national power system is 50 Hz. Under normal conditions, the system frequency fluctuates within ± 0.2 Hz from the designated frequency. In cases where the power system has not yet stabilized, the system frequency may fluctuate within ± 0.5 Hz from the designated frequency.

Article 5. Voltage

1. Designated voltage levels in the distribution power system

The designated voltage levels in the distribution power system include 110 kV, 35 kV, 22 kV, 15 kV, 10 kV, 06 kV, and 0.4 kV.

2. During normal operation, the allowable operating voltage at the point of connection may fluctuate from the designated voltage as follows:

a) At the point of connection with electricity users: ± 05 %.

b) At the point of connection with power plants: + 10% and - 05 %.

c) In cases where power plants and electricity users are connected to the same busbar on the distribution network, the voltage at the point of connection shall be determined by the Distribution Unit managing the regional power grid operation to ensure compliance with technical requirements for distribution network operation and to ensure the quality of supply voltage for electricity users.

3. During single fault conditions or during the process of restoring stable operation following a fault, fluctuations in voltage at the point of connection with directly affected electricity users are allowed within + 05 % and - 10 % from the designated voltage.

4. During severe system transmission faults or during fault restoration, fluctuations in voltage are allowed within ± 10 % from the designated voltage.

5. In cases where electricity users require higher voltage quality than stipulated in Clause 2 of this Article, electricity users can negotiate with the Distribution Unit or the Distribution and Retail Electricity Unit.

Article 6. Phase Balance

During normal operation, the component of phase voltage inverse sequence does not exceed 03 % of the designated voltage for the 110 kV voltage level or 05 % of the designated voltage for medium and low voltage levels.

Article 7. Voltage Harmonic Distortion

1. Total harmonic distortion (THD) is the ratio between the effective value of the harmonic voltage wave and the effective value of the fundamental voltage wave (in percentage units), calculated according to the following formula:

Where:

a) THD: Total harmonic distortion;

b) V_{ANNEX I.A[31]}: Effective value of the ith harmonic voltage wave, where N is the highest harmonic order to be evaluated;

c) V₁: Effective value of the fundamental voltage wave (at 50 Hz).

2. The total harmonic distortion at all points of connection must not exceed the limits specified in Table 1 as follows:

Table 1. Voltage Harmonic Distortion

3. Abnormal peak voltage spikes on the distribution network are permitted to exceed the total harmonic distortion limit specified in Clause 2 of this Article for short periods without causing damage to distribution network equipment.

Article 8. Voltage Fluctuation

1. Under normal operating conditions, the voltage fluctuation level at all points of connection must not exceed the limits specified in Table 2 as follows:

Table 2: Voltage Fluctuation Levels

Where:

a) Short-term voltage fluctuation level (P_st) is the measured value obtained over a 10-minute period using standard measuring equipment according to IEC868. P_st95% is the threshold value of P_st such that in 95 % of the measurement time (at least one week) and 95 % of the measurement locations, P_st does not exceed this value.

b) Long-term voltage fluctuation level (P_lt) is calculated from 12 consecutive measurements of P_st (over a two-hour period), according to the formula:

"5. The pre-tax weighted average cost of capital i (%) is determined according to the formula below:_lt95% is the threshold value of P_lt such that in 95 % of the measurement time (at least one week) and 95 % of the measurement locations, P_lt does not exceed this value.

2. At medium and low voltage points of connection, the short-term voltage fluctuation level (P_stst_lt) must not exceed 0.9 and the long-term voltage fluctuation level (P

Article 9. Short Circuit Current and Fault Clearance Time

1. The maximum allowable short circuit current and the maximum fault clearance time for the main protection are specified in Table 3 as follows:

Table 3. Maximum Allowable Short Circuit Current and Maximum Fault Clearance Time for Main Protection

2. For medium voltage distribution networks supplying densely populated urban areas with many segmented lines, where coordination between switching devices on the network is difficult, the fault clearance time for the main protection at certain switch locations may exceed the value prescribed in Clause 1 of this Article but must be less than 01 second (s) and must ensure safety for equipment and the network.

3. Distribution units must notify the maximum allowable short circuit current at the point of connection to large customers using the distribution network for investment and installation of equipment.

Article 10. Grounding System

1. The neutral grounding system in the distribution network is specified in Table 4 as follows:

Table 4. Grounding System

2. In cases where the neutral grounding system in the distribution network is implemented differently from the provisions of Clause 1 of this Article, it must have the written consent of the National Power System Dispatching Unit.

Article 11. Earth Fault Factor

The earth fault factor of the distribution network shall not exceed 1.4 for networks with directly grounded neutral and 1.7 for networks with isolated neutral or networks with neutral grounded through impedance.

Section 2

RELIABILITY OF POWER SUPPLY AND ENERGY LOSSES

Article 12. Indices of Reliability of Power Supply in Distribution Networks

1. The indices of reliability of power supply in distribution networks include:

a) The index of average outage duration of the distribution network (System Average Interruption Duration Index - SAIDI);

b) The index of average number of outages of the distribution network (System Average Interruption Frequency Index - SAIFI);

c) The index of average number of momentary interruptions of the distribution network (Momentary Average Interruption Frequency Index - MAIFI).

2. The indices of reliability of the distribution network are calculated as follows:

a) SAIDI is calculated by dividing the total outage duration exceeding five minutes of electricity users and electricity distributors and retailers purchasing electricity from the distribution unit by the total number of electricity users and electricity distributors and retailers purchasing electricity from the distribution unit, determined according to the following formula:

Where:

- T_{ANNEX I.A[31]}: Outage duration of the i-th outage in month t (only considering outages lasting more than five minutes);

- K_{ANNEX I.A[31]}: Total number of electricity users and electricity distributors and retailers purchasing electricity from the distribution unit affected by the i-th outage in month t;

- n: Total number of outages exceeding five minutes in month t within the scope of the distribution unit's supply;

- K_{organize credit institutions, foreign bank branches are responsible for organizing the implementation of this Circular.}: Total number of electricity users and electricity distributors and retailers purchasing electricity from the distribution unit in month t;

- SAIDI_{organize credit institutions, foreign bank branches are responsible for organizing the implementation of this Circular.} (minutes): Index of average outage duration of the distribution network in month t;

- SAIDI_y (minutes): Index of average outage duration of the distribution network in year y.

b) SAIFI is calculated by dividing the total number of outages exceeding five minutes experienced by electricity users and electricity distributors and retailers purchasing electricity from the distribution unit by the total number of electricity users and electricity distributors and retailers purchasing electricity from the distribution unit, determined according to the following formula:

Where:

- n: Total number of outages exceeding five minutes in month t within the scope of the distribution unit's supply;

- K_{ANNEX I.A[31]}: Total number of electricity users and electricity distributors and retailers purchasing electricity from the distribution unit affected by the i-th outage in month t;

- K_{organize credit institutions, foreign bank branches are responsible for organizing the implementation of this Circular.}: Total number of electricity users and electricity distributors and retailers purchasing electricity from the distribution unit in month t;

- SAIFI_{organize credit institutions, foreign bank branches are responsible for organizing the implementation of this Circular.}: Index of average number of outages of the distribution network in month t;

- SAIFI_y: Index of average number of outages of the distribution network in year y.

c) MAIFI is calculated by dividing the total number of momentary interruptions (outages lasting up to five minutes) experienced by electricity users and electricity distributors and retailers purchasing electricity from the distribution unit by the total number of electricity users and electricity distributors and retailers purchasing electricity from the distribution unit, determined according to the following formula:

Where:

- n: Total number of momentary interruptions in month t within the scope of the distribution unit's supply;

- K_{ANNEX I.A[31]}: Total number of electricity users and electricity distributors and retailers purchasing electricity from the distribution unit affected by the i-th momentary interruption in month t;

- K_{organize credit institutions, foreign bank branches are responsible for organizing the implementation of this Circular.}: Total number of electricity users and electricity distributors and retailers purchasing electricity from the distribution unit in month t;

- MAIFI_{organize credit institutions, foreign bank branches are responsible for organizing the implementation of this Circular.}: Index of average number of momentary interruptions of the distribution network in month t;

- MAIFI_y: Index of average number of momentary interruptions of the distribution network in year y.

Article 13. Power Supply Reliability Indexes

1. Power supply reliability is statistically analyzed and evaluated through two sets of indexes including "Overall Power Supply Reliability" and "Distribution Network Power Supply Reliability". Each set of power supply reliability indexes includes three indexes: SAIDI, SAIFI, and MAIFI, as defined in Article 12 of this Circular.

2. The "Overall Power Supply Reliability" index is used to assess the quality of power supply to electricity customers of the Distribution Unit and is calculated according to the provisions of Article 12 of this Circular without considering the following cases of power outages:

a) Customers requesting disconnection from the distribution network;

b) Customer equipment on the distribution network not meeting technical and safety requirements for resuming power supply;

c) Due to customer equipment failures on the distribution network;

d) Due to unforeseeable events beyond the control of the Distribution Unit or due to violations of legal regulations by customers using the distribution network as stipulated in the Conditions and Procedures for Interrupting or Reducing Electricity Supply issued by the Ministry of Industry and Trade.

3. The "Distribution Network Power Supply Reliability" index is one of the criteria used to evaluate the operational efficiency of the Distribution Unit and is calculated according to the provisions of Article 12 of this Circular without considering the following cases of power outages:

a) Cases specified in Clause 2 of this Article;

b) Due to power outages from the transmission system;

c) Shedding loads upon dispatch orders from the controlling authority;

d) Disconnection when there is a risk of serious safety hazards to people and equipment during system operation.

Article 14. Losses in Distribution Network Electricity

Losses in distribution network electricity include:

1. Technical losses are losses caused by the physical nature of electrical conductors and equipment on the distribution network.

2. Non-technical losses are losses resulting from management and business factors during the electricity supply process that are not due to the physical nature of electrical conductors and equipment on the distribution network.

Article 15. Procedure for Approving Annual Power Supply Reliability Targets and Electricity Losses in the Distribution Network

1. Before November 15 each year, the Vietnam Electricity Corporation is responsible for developing plans regarding power supply reliability and electricity losses for the next year for each Distribution Unit to submit to the Electricity Regulatory Authority for review and approval.

2. Before December 15 each year, the Electricity Regulatory Authority approves the power supply reliability targets and electricity losses for each Distribution Unit as the basis for calculating distribution costs for the Distribution Units.

Section 3

REQUIREMENTS FOR CUSTOMER SERVICE QUALITY

Article 16. Customer Service Quality Indicators

1. Time taken to review, sign agreements for connection and implement new connections or adjustments to existing connections for customers.

2. Time to notify customers of interruptions or reductions in power supply levels.

3. Quality of written responses to customer complaints and suggestions is assessed based on the following criteria:

a) Clarity in written responses to customer complaints and suggestions, which must include the following contents:

- Whether the complaint is accepted or not;

- A clear explanation of the resolution plan if the complaint is accepted;

- In cases where the complaint is not accepted, the Distribution Unit or the Distribution and Retail Unit must clearly state the reasons and guide customers accordingly;

- Provision of all necessary information to enable customers to evaluate the resolution plan.

b) The ratio of written responses to customer complaints within the time frame specified in Point c, Clause 2, Article 17 of this Circular.

4. Quality of telephone complaint handling is assessed based on the ratio of customer calls received within the time frame specified in Point d, Clause 2, Article 17 of this Circular.

Article 17. Customer Service Quality Requirements

1. Electricity Distribution Units and Electricity Distribution and Retail Units must organize, maintain, and update information systems to record all customer complaints and grievances submitted in writing or via telephone.

2. Customer service quality requirements are specified as follows:

a) The time for reviewing and signing the Connection Agreement from the date of receiving a complete and valid connection application file as stipulated in Clause 45 of this Circular;

b) The time for notifying the interruption or reduction of electricity supply according to the regulations on conditions and procedures for interrupting or reducing electricity supply issued by the Ministry of Industry and Trade;

c) Quality of written responses to customer complaints: Over 95% of written complaint response documents contain clear answers and comply with legal provisions within five working days;

d) Quality of telephone complaint reception: Over 80% of customer calls are received within thirty seconds.

Chapter III

FORECAST OF DISTRIBUTION SYSTEM ELECTRICITY DEMAND

Article 18. General Provisions on Forecast of Distribution System Electricity Demand

1. Forecast of distribution system electricity demand is a forecast for all electricity loads supplied from the distribution system, excluding loads with their own power supply sources. The forecast of distribution system electricity demand serves as the basis for annual investment development plans for distribution networks, operation plans for distribution systems, national power system operation plans, and electricity market operation plans.

2. Forecast of distribution system electricity demand includes annual, monthly, and weekly forecasts.

3. Responsibilities for forecasting distribution system electricity demand

a) Electricity Distribution and Retail Units and Large Customers using distribution networks have the responsibility to provide Electricity Distribution Units with forecast data on their electricity demand, including comprehensive forecast data for the entire unit and electricity demand at each connection point;

b) Provincial Power Companies have the responsibility to forecast electricity demand for the distribution system within their management scope, including forecasts at connection points with transmission networks;

c) National Power Holding Corporation has the responsibility to forecast electricity demand for the distribution system within its management scope, including forecasts at all connection points with transmission networks based on the results of electricity demand forecasts by provincial power companies under its jurisdiction and large customers using distribution networks.

4. National Power Holding Corporation has the responsibility to conduct load research for electricity demand forecasting and to calculate retail electricity prices according to the content, methods, procedures, and formalities for conducting electricity load research prescribed by the Ministry of Industry and Trade.

5. The Electricity Regulatory Authority has the responsibility to organize the development and issuance of the Process for Forecasting National Power System Load.

Article 19. Annual Forecast of Distribution System Electricity Demand

1. Information and data used for annual forecast of distribution system electricity demand include:

a) Forecast data on electricity demand in approved provincial and centrally-administered city power development master plans;

b) Factors such as electricity prices, population growth rates, economic development trends in the area managed by Electricity Distribution Units, and other relevant socio-economic factors;

c) Trends in electricity demand over the past five years;

d) Forecasts of growth in electricity demand for existing loads in future years;

đ) Electricity demand for new loads, projects, industrial zones, and clusters that have planned investments and operational schedules;

e) Energy-saving programs, load management programs, and measures to reduce electricity losses;

g) Capacity and volume of electricity purchased and sold at each connection point with other distribution networks;

h) Capacity and volume of imported and exported electricity (if applicable);

i) Social factors and events affecting electricity demand.

2. Results of annual forecast of distribution system electricity demand

a) For the first year

- Forecast data on monthly electricity consumption and peak capacity for the entire Electricity Distribution Unit and at each connection point with the transmission network;

- Typical daily load profile charts for each month for the entire Electricity Distribution Unit and at each connection point with the transmission network.

b) For the next four years

- Forecast data on annual electricity consumption and peak capacity for the entire Electricity Distribution Unit and at each connection point with the transmission network;

- Typical daily load profile charts for each year for the entire Electricity Distribution Unit and at each connection point with the transmission network.

3. Responsibilities for providing information to serve the forecast of distribution system electricity demand

a) Customers with average electricity consumption of 1,000,000 kWh/month or more have the responsibility to provide the following information:

- Current typical daily load profile chart;

- Estimated maximum capacity and monthly electricity consumption registered for use in the coming year; estimated maximum capacity and annual electricity consumption registered for use in the next four years;

- Additional grid parameters, circuit breakers, and protection layout diagrams for equipment directly connected or affecting the distribution network.

b) Large customers using distribution networks who own generating units have the responsibility to provide the following information:

- Forecast of monthly generation capacity and volume that can be fed into the distribution network;

- Technical specifications of new generating units and their commissioning schedule over the next five years.

c) Electricity Distribution and Retail Units have the responsibility to provide the following information:

- Total number of customers and electricity consumption statistics by category over the past five years;

- Forecast of capacity and electricity demand for customer categories over the next five years;

- Typical daily load profile chart at the connection point for the coming year;

- Additional grid parameters, circuit breakers, and protection layout diagrams for electrical equipment directly connected or affecting the distribution network.

d) An electrical distribution unit connecting to another distribution network must provide information on the maximum capacity and expected power exchange at the connection point for each month of the upcoming year; the maximum capacity and expected power exchange at the connection point for each year during the subsequent four-year period.

4. Procedure

a) Before July 1st of each year, entities specified in Clause 3 of this Article must provide information to the distribution unit to prepare forecasts of electricity demand for the upcoming year and the following four years.

b) Before August 1st of each year, the Electricity Distribution Corporation must complete the annual electricity demand forecast results as stipulated in Clause 2 of this Article to provide to the National Power System Dispatching Unit.

Article 20. Monthly Electricity Demand Forecast

1. Information and data used for monthly electricity demand forecasting a) Annual electricity demand forecast results;

b) Statistics on electricity consumption, peak day and night power in the corresponding month of the previous year;

c) Other necessary information.

2. Results of monthly electricity demand forecasting

a) Maximum capacity and weekly electricity consumption of the entire distribution unit and at each connection point with the transmission network;

b) Maximum capacity and weekly power exchange at points of international electricity trade through the distribution network;

c) Maximum capacity and weekly power exchange of large customers using the distribution network;

d) Typical daily work, rest, and holiday load profiles for the entire distribution unit on a weekly basis.

3. Large customers using the distribution network shall be responsible for providing the distribution unit with forecasts of electricity consumption and maximum capacity for the upcoming month at connection points under the following circumstances:

a) A difference in electricity consumption exceeding 2 MW compared to the corresponding month's figures in the annual electricity demand forecast;

b) A difference in power generation exceeding 1 MW compared to the expected power generation of the corresponding month in the annual electricity demand forecast.

4. Procedure

a) Before the 15th of each month, large customers using the distribution network must provide the distribution unit with the information as prescribed in Clause 3 of this Article to serve the monthly electricity demand forecast for the upcoming month.

b) Before the 20th of each month, the Electricity Distribution Corporation must complete the forecast of electricity demand for the upcoming month and notify the National Power System Dispatching Unit.

Article 21. Weekly Electricity Demand Forecast

1. The results of weekly electricity demand forecasting include the following parameters:

a) Maximum capacity and daily electricity consumption of the entire distribution unit and at each connection point with the transmission network;

b) Maximum capacity and daily power exchange at points of international electricity trade through the distribution network;

c) Daily load profile throughout the week for the entire distribution unit.

2. By 10:00 AM every Tuesday, the Electricity Distribution Corporation is responsible for completing and providing to the National Power System Dispatching Unit the forecast of electricity demand for the next two weeks to establish operational methods for the next two weeks.

Chapter IV

DISTRIBUTION NETWORK DEVELOPMENT INVESTMENT PLAN

Article 22. General Provisions on the Investment Plan for Developing Distribution Grids

1. Annually, the Electricity Corporation shall be responsible for establishing the investment plan for developing distribution grids within its management scope for the upcoming year and considering the next two years.

2. The annual investment plan for developing distribution grids shall be established based on the following foundations:

a) The results of electricity load demand forecasting for the year;

b) Compliance with the approved provincial and centrally-administered city power development planning and grid connection agreements already signed.

Article 23. Requirements for the Annual Investment Plan for Developing Distribution Grids

1. Ensuring electricity supply to meet the current customers' load demand and new expected customers; connecting new power sources to the distribution grid.

2. Meeting the operational requirements of the distribution grid system as stipulated in Chapter II of this Circular.

3. Proposing a detailed list and schedule for putting into operation distribution grid projects that need investment in the upcoming year and the total investment volume according to project categories for the next two years.

4. Proposing a list of transmission grid projects that need investment and upgrading to meet the progress requirements of distribution grid projects in the investment development plan.

Article 24. Contents of the Investment Plan for Developing Distribution Grids

The investment plan for developing distribution grids includes the following main contents:

1. Evaluation of the current status of the distribution grid.

2. Forecasting the electricity load demand for the upcoming year, considering the next four years as specified in Article 19 of this Circular.

3. Evaluating the implementation of investments in distribution grid projects that have been approved in the previous year's investment development plan.

4. List of new grid connection points with large customers using the distribution grid, including proposed grid connection points that have been agreed upon.

5. Calculations and analyses for selecting the optimal grid configuration, including:

a) Calculation of the distribution grid operation mode;

b) Calculation of short-circuit currents to the medium-voltage busbars of 110 kV substations;

c) Calculation of voltage losses on the distribution grid;

d) Calculation of energy losses on the distribution grid;

đ) Calculation of reactive power compensation;

e) Plan for implementing reactive power compensation on the distribution grid.

6. List of new distribution grid lines and substation construction or renovation projects for the upcoming year and the total construction and renovation investment volume for the distribution grid according to voltage levels and project categories for the next two years as prescribed in Appendix 1 issued together with this Circular.

7. Summary of new construction and renovation investment volumes for the distribution grid according to voltage levels.

Article 25. Approval Procedure for the Investment Plan for Developing Distribution Grids

1. Before September 15 each year, the Electricity Corporation shall be responsible for establishing the annual investment plan for developing distribution grids, including the contents stipulated in Article 24 of this Circular, and reporting to the Vietnam Electricity Group for approval.

2. Before October 1 each year, the Electricity Corporation shall be responsible for submitting the annual investment plan for developing distribution grids, which has been approved by the Vietnam Electricity Group, to the Electricity Regulatory Authority for review.

3. Before October 15 each year, the Electricity Regulatory Authority shall be responsible for organizing the review and approval of the Electricity Corporation's investment plan for developing distribution grids to ensure safe operation of the distribution grid system, electricity supply for economic and social development, and electricity price formulation.

Chapter V

GRID CONNECTION TO THE DISTRIBUTION GRID

Section 1

GENERAL PRINCIPLES

Article 26. Connection Points

1. Connection points in the distribution power system include:

a) The point where customers' equipment, networks, and power plants connect to the distribution network of the Distribution Unit;

b) The point where equipment and networks between two Distribution Units connect;

c) The point where customers' equipment and networks connect to the distribution network of the Distribution and Retail Unit.

2. Connection points must be described in detail through drawings, diagrams, and explanations related to the Connection Agreement or power purchase contract.

Article 27. Property Boundaries and Management Operation

1. The property boundary between the Distribution Unit or the Distribution and Retail Unit and the customer using the distribution network is the connection point.

2. Each party's assets at the property boundary must be listed in detail along with relevant drawings and diagrams in the Connection Agreement or power purchase contract.

3. The party owning the asset is responsible for investing, constructing, managing, and operating it according to legal standards and regulations, except where otherwise agreed.

Article 28. Compliance with Power Development Planning

1. The plan to connect new substations, networks, and power plants to the distribution network must comply with the approved power development planning by competent state authorities.

2. In cases where the customer's proposed connection plan does not comply with the approved power development planning, the Distribution Unit or the Distribution and Retail Unit has the responsibility to notify the customer using the distribution network to adjust and supplement the planning according to the provisions on the content, procedures, and approval process for power development planning issued by the Ministry of Industry and Trade.

Article 29. Responsibilities for Compliance with Connection Requirements and Coordination in Connection Implementation

1. The Distribution Unit and the customer using the distribution network have the responsibility to comply with the connection requirements for their owned electrical equipment as stipulated in this Circular.

2. The Distribution Unit is responsible for coordinating the implementation of the connection plan when the customer submits a valid connection application. The connection and adjustment of connections must meet the technical requirements for connection equipment specified in Section 2 of this Chapter.

3. In cases where the equipment at the customer's connection point does not meet the technical requirements and operational requirements of the distribution network, the Distribution Unit has the responsibility to notify and coordinate with the customer to develop corrective measures. The customer using the distribution network must bear all costs for implementing these corrective measures.

4. The Distribution Unit is responsible for issuing internal procedures to implement its work contents, coordinating with customers to shorten the time for implementing connection agreements, and connecting customers.

Section 2

TECHNICAL REQUIREMENTS FOR CONNECTION EQUIPMENT

Article 30. Requirements for Electrical Equipment at Connection Points

1. The main electrical connection diagram must include all medium and high voltage electrical equipment at the connection point, showing the interconnection between the customer's network and the distribution network. Electrical equipment must be described using standard symbols and named and numbered according to the National Electricity System Operating Procedures issued by the Ministry of Industry and Trade.

2. Circuit breakers directly connected to the connection point and accompanying protection, control, and measurement systems must be capable of interrupting the maximum short-circuit current at the connection point to meet the network development diagram for the next ten years.

3. Circuit breakers performing operations at the connection point between power plants and the distribution network must be equipped with synchronization checking systems.

Article 31. Requirements for Phase Balance

In normal operating conditions, customers using distribution networks must ensure that their equipment does not cause the phase voltage component at the point of connection to exceed 3% of the rated voltage for 110 kV voltage levels or more than 5% of the rated voltage for voltage levels below 110 kV.

Article 32. Requirements for Harmonic Current Waveform Distortion

1. The maximum allowable value of the total harmonic current waveform distortion caused by the load is specified as follows:

a) For connections to medium and low voltage levels with power less than 50 kW: The high-order harmonic current value shall not exceed 20% of the load current;

b) For connections to high voltage levels or connections with power from 50 kW upwards: The high-order harmonic current value shall not exceed 12% of the load current.

2. The total harmonic current waveform distortion measured by the Distribution Unit at the customer's point of connection on the distribution network shall be measured according to standard IEC1000-4-7, lasting at least 24 hours with a cycle of once every ten minutes. At the latest six months from the date of detection that the customer's equipment does not meet the values prescribed in Clause 1 of this Article, the customer must apply corrective measures to achieve the total harmonic current waveform distortion within the permissible limits.

Article 33. Requirements for Voltage Fluctuations

The maximum allowable level of voltage fluctuations at the point of connection to the distribution network must comply with the provisions of Article 8 of this Circular.

Article 34. Requirements for Grounding Systems

1. Customers using distribution networks must apply neutral grounding systems in their networks as stipulated in Article 10 of this Circular, except where there is an agreement to the contrary and with the consent of the Control Authority having control rights.

2. In cases where customers are supplied electricity from multiple sources, customers are responsible for installing appropriate protective devices to prevent and limit currents flowing through the neutral point to ground.

Article 35. Requirements for Power Factor

Customers using electricity for production, business, and services with their own transformer substation or without a separate transformer substation but with a maximum usage capacity of 40 kW or more are responsible for maintaining the power factor (cosj) at the point of installation of the electricity meter according to the power purchase contract not less than 0.9.

Article 36. Requirements for Protection Systems

1. The relay protection system of substations, 110 kV transmission lines, and generator units of power plants connected to the 110 kV grid must comply with the Technical Requirements for Relay Protection and Automation Systems in Power Plants and Substations issued by the Electricity Regulatory Authority.

2. The Distribution Unit and customers using distribution networks with their own substations have the responsibility to design, install, adjust, test, and operate the protection system on the network within their management scope to meet standards and requirements regarding response time, sensitivity, and selectivity when isolating faults, ensuring safe and reliable operation of the distribution network.

3. The Distribution Unit and customers using distribution networks with their own substations must agree on the requirements for the protection system in the Connection Agreement. The coordination of the installation of relay protection devices at the point of connection must be agreed upon between the Distribution Unit, the customer using the distribution network, and the Control Authority having control rights during the connection negotiation process.

4. The Distribution Unit must provide customers using distribution networks with their own substations with the parameters of the relay protection system on the distribution network directly related to the customer's protection system at the point of connection during the connection negotiation process. The Control Authority having control rights is responsible for calculating, checking, and issuing relay protection setting sheets or passing setting values on the distribution network under its control according to the National System Operation Procedures issued by the Ministry of Industry and Trade.

5. Customers using distribution networks with their own substations may not arbitrarily install equipment to limit short-circuit currents at the busbar connecting to the distribution network, except where there is an agreement with the Distribution Unit and the Control Authority having control rights.

6. In addition to the requirements stipulated in Clauses 1, 2, 3, 4, and 5 of this Article, the protection systems of power plants and customers using distribution networks with their own substations connected to the 110 kV voltage level must meet the following requirements:

a) 110 kV transmission lines connecting power plants to the national power system must have two (2) communication channels for relaying protection signals between both ends of the line with a transmission time not exceeding 20 ms;

b) Customers using distribution networks with their own substations connected to the 110 kV voltage level are responsible for investing in and installing low-frequency relays to serve automatic load shedding according to calculations by the Control Authority having control rights.

Article 37. Requirements for Information Systems

1. Power plants connected to distribution networks with a capacity of 10 MW or more, or 110 kV substations must be equipped with information systems and connect these systems compatibly with the information system of the Control Center responsible for communication and data transmission during power system operation. The minimum communication means serving dispatch work include direct lines, telephones, and fax machines must operate well.

2. Requirements for information systems not covered by Clause 1 of this Article shall be agreed upon uniformly by relevant units and clearly recorded in the Connection Agreement.

3. Distribution companies and customers using distribution networks have the responsibility to invest, manage, and operate information systems within their management scope to ensure continuous and reliable information about the Control Center responsible for control to serve distribution network operation.

4. The Control Center responsible for control and the Distribution Company have the responsibility to coordinate in providing customers using distribution networks with requirements for data information, necessary information interfaces, and cooperate with customers in testing, inspecting, and connecting customer information systems and data with existing information systems and data within the management scope to serve distribution network operation.

Article 38. Requirements for SCADA System Connections

1. Power plants connected to distribution networks with a capacity of 10 MW or more (regardless of connection voltage level) and 110 kV substations that have not yet been connected to the Control Center must be equipped with Gateway or RTU with two (2) direct, simultaneous, and physically independent connections to the SCADA system of the Control Center responsible for control. In cases where power plants or substations have multiple control centers responsible for control, the control centers are responsible for sharing information to facilitate coordinated power system operation.

2. Power plants connected to distribution networks with a capacity of 10 MW or more that have already been connected to the Control Center must be equipped with Gateway or RTU set up with one (1) direct connection to the SCADA system of the Control Center responsible for control and two (2) direct connections to the control system at the Control Center. 110 kV substations controlled and operated remotely from the Control Center must be equipped with Gateway or RTU set up with two (2) direct connections to the control system at the Control Center. SCADA connection information and data of these power plants and substations must ensure real-time connection and sharing with the SCADA system of the Control Center responsible for control to serve operation and dispatch of the power system.

3. Requirements for connecting to the SCADA system of the Control Center responsible for control not covered by Clauses 1 and 2 of this Article must be agreed upon uniformly by relevant units and clearly recorded in the Connection Agreement. In this case, the Distribution Company has the responsibility to coordinate with the Control Center responsible for control to unify the SCADA system connection requirements in the Connection Agreement.

4. The terminal equipment RTU/Gateway of the Distribution Company and customers using distribution networks must have technical characteristics compatible and ensure connection to the SCADA system of the Control Center responsible for control.

5. The owner of power plants and substations has the responsibility to invest, install, manage, and operate terminal equipment RTU/Gateway within their management scope, data transmission paths, or leased from service providers to ensure continuous and reliable connection and data transmission to the SCADA system of the Control Center responsible for control.

6. The Control Center responsible for control has the responsibility to integrate data according to the agreed data list with the Distribution Company and customers using distribution networks into its SCADA system. The Distribution Company and customers using distribution networks have the responsibility to configure and establish databases on their systems to ensure compatibility with the SCADA system of the Control Center responsible for control and to coordinate with the Control Center during implementation.

7. In cases where the SCADA system of the Control Center responsible for control undergoes technological changes approved by competent authorities after signing the Connection Agreement leading to changes or upgrades in control systems, terminal equipment RTU/Gateway of the Distribution Company and customers using distribution networks, the Control Center responsible for control, the Distribution Company, and customers using distribution networks have the responsibility to coordinate in implementing necessary adjustments so that customer equipment and Distribution Company equipment are compatible with SCADA system changes. The Distribution Company and customers using distribution networks have the responsibility to invest in and upgrade control systems, terminal equipment RTU/Gateway to ensure compatible connection with the SCADA system of the Control Center responsible for control.

8. The list of data requirements and technical requirements for terminal equipment RTU/Gateway are specifically stipulated in the Technical Requirements and Operation Management Regulations for SCADA Systems issued by the Electricity Regulatory Authority.

9. The Electricity Regulatory Authority has the responsibility to organize the development and issuance of Technical Requirements and Operation Management Regulations for SCADA Systems.

Article 39. Requirements for generating units of hydropower plants and thermal power plants connected to distribution networks

1. Requirements for generating units of power plants with total installed capacity exceeding 30 MW connected to distribution networks shall comply with technical requirements set forth in the Transmission System Regulations issued by the Ministry of Industry and Trade.

2. Requirements for generating units of hydropower plants and thermal power plants (including biomass power plants, biogas power plants, and waste-to-energy power plants) with total installed capacity up to 30 MW

a) Must be able to continuously generate rated active power within the frequency range from 49 Hz to 51 Hz. Within the frequency range from 47.5 Hz to 49 Hz, the reduction in power must not exceed the value calculated according to the system frequency reduction requirement ratio, consistent with the characteristic curve relationship between active power and frequency of the generating unit. The minimum time to maintain operation corresponding to each frequency band of the system is specified in Table 5 as follows:

Table 5. Minimum Time to Maintain Operation Corresponding to Each Frequency Band of the Power System

b) Generating units connected to distribution networks must have the ability to continuously generate and absorb reactive power with a power factor of 0.9 (corresponding to the mode of generating reactive power) to 0.95 (corresponding to the mode of absorbing reactive power) at rated power and maintain voltage deviation within the range specified in Article 5 of this Circular;

c) Generating units connected to distribution networks must be capable of withstanding asymmetrical voltage loss levels in the power system as stipulated in Article 6 of this Circular and withstand zero-sequence and negative-sequence current components not less than the time to clear phase-phase and phase-ground short circuits near the generator using backup protection associated with the point of connection;

d) In case the point of connection is equipped with automatic reclosing devices, the relay protection system of the power plant must ensure coordination with the automatic reclosing devices of the Distribution Unit and must be designed to disconnect the generating unit from the distribution network immediately after the first opening of circuit breakers, automatic reclosing devices, or sectionalizing switches of the distribution network and maintain isolation of the generating unit from the distribution network until the distribution network is fully restored;

đ) Power plants with total installed capacity up to 30 MW connected to the 110 kV distribution network must be equipped with speed regulators capable of operating with static characteristics adjustment values in the range from 03% to 05% and deadband of the regulator within ± 0.05 Hz.

Article 40. Requirements for wind power plants and solar power plants connected to distribution networks from medium voltage and above

1. Wind power plants and solar power plants must be capable of operating to generate active power within the frequency range from 49 Hz to 51 Hz under the following modes:

a) Free generation mode: operate to generate maximum possible power according to the primary energy source variation (wind or sun).

b) Active power control mode:

Wind power plants and solar power plants must be capable of adjusting active power generation according to dispatch orders from the Dispatch Authority within a time not exceeding 30 seconds with an error margin within ± 01% of rated power, specifically as follows:

- Generate power according to dispatch instructions when the primary source varies by or more than the forecasted value;

- Generate maximum possible power when the primary source varies below the forecasted value.

2. Wind power plants and solar power plants must be capable of maintaining operation to generate power for a minimum time corresponding to each operational frequency band as specified in Table 5 Point a Clause 2 Article 39 of this Circular at all times while connected to the grid.

3. When the system frequency exceeds 51 Hz, wind power plants and solar power plants must reduce active power at a rate of not less than 01% of rated power per second. The level of power reduction corresponding to frequency is determined by the following formula:

Where:

a) ΔP: Level of active power reduction (MW);

b) P_m: Active power corresponding to the moment before power reduction (MW);

c) f_n: System frequency before power reduction (Hz).

4. Wind power plants and solar power plants connected to distribution networks must be capable of adjusting reactive power and voltage as follows:

a) In case the power plant generates active power greater than or equal to 20% of rated active power and voltage is within normal operating range, the power plant must be capable of continuously adjusting reactive power within the power factor range of 0.95 (corresponding to the mode of generating reactive power) to 0.95 (corresponding to the mode of absorbing reactive power) at the point of connection at rated power;

b) In case the power plant generates active power less than 20% of rated power, the power plant may reduce its capability to absorb or generate reactive power in accordance with the characteristics of the generating unit;

c) In case the voltage at the point of connection is within ± 10% of rated voltage, the power plant must be capable of adjusting voltage at the point of connection with an error margin not exceeding ± 0.5% of rated voltage (compared to the set voltage) throughout the entire permissible operating range of the generator and complete within a time not exceeding 02 minutes;

d) In case the voltage at the point of connection is outside the range of ± 10% of rated voltage, the power plant must be capable of generating or absorbing reactive power (in proportion to rated reactive power) at least twice the rate of change of voltage at the point of connection.

5. Wind power plants and solar power plants must be capable of maintaining operation to generate power corresponding to the voltage range at the point of connection for the following duration:

a) Voltage below 0.3 pu (pu is a relative unit system representing the ratio between actual voltage value and rated voltage value), the minimum retention time is 0.15 seconds.

b) Voltage from 0.3 pu to less than 0.9 pu, the minimum retention time is calculated according to the following formula:

Where:

T_{Maximum Downhill Gradient} = 4 x U - 0.6

- T_{Maximum Downhill Gradient} (seconds): Minimum generation retention time;

- U (pu): Actual voltage at the point of connection expressed in pu units.

c) Voltage from 0.9 pu to less than 1.1 pu, wind power plants and solar power plants must maintain continuous operation for power generation.

d) Voltage from 1.1 pu to less than 1.15 pu, wind power plants and solar power plants must maintain operation for power generation for a duration of three seconds.

đ) Voltage from 1.15 pu to less than 1.2 pu, wind power plants and solar power plants must maintain operation for power generation for a duration of 0.5 seconds.

6. Wind power plants and solar power plants must ensure that the harmonic component of phase voltage at the point of connection does not exceed 01 % of the rated voltage. Wind power plants and solar power plants must be capable of withstanding the harmonic component of phase voltage at the point of connection up to 03 % of the rated voltage for 110 kV voltage level or up to 05 % of the rated voltage for voltage levels below 110 kV.

7. The total level of harmonic waveform distortion caused by wind power plants and solar power plants at the point of connection shall not exceed a value of 03 %.

8. The voltage flicker level caused by wind power plants and solar power plants at the point of connection shall not exceed the value specified in Article 8 of this Circular.

Article 41. Requirements for Solar Power Systems Connected to Distribution Grids at Low Voltage Levels

Solar power systems are permitted to connect to low-voltage distribution grids when they meet the following requirements:

1. Connection Capacity

a) The total installed capacity of solar power systems connected to the low-voltage side of a substation transformer shall not exceed 30 % of the installed capacity of that substation transformer;

b) Solar power systems with a capacity of 03 kVA or less may be connected to a single-phase or three-phase low-voltage distribution grid;

c) Solar power systems with a capacity from 03 kVA to 100 kVA (but not exceeding 30 % of the installed capacity of the substation transformer being connected) may be connected to a three-phase low-voltage distribution grid.

2. Solar power systems must have the capability to maintain continuous operation for power generation within a frequency range of 49 Hz to 51 Hz. When the system frequency falls outside the range of 49 Hz to 51 Hz, the solar power system must be able to maintain operation for power generation for a minimum duration of 0.2 seconds.

3. Solar power systems must have the capability to maintain continuous operation for power generation when the voltage at the point of connection is within the range of 85 % to 110 % of the rated voltage. When the voltage at the point of connection falls outside the range of 85 % to 110 % of the rated voltage, the solar power system must be able to maintain operation for power generation for a minimum duration of two seconds.

4. Solar power systems shall not cause the intrusion of direct current into the distribution network exceeding 0.5 % of the rated current at the point of connection.

5. Solar power systems must be equipped with protective devices to ensure fault exclusion and safe operation of the solar power system. For solar power systems with a capacity of 10 kVA or more, customers requesting connection must agree on protection system requirements with the Distribution Unit.

6. Solar power systems connected to low-voltage distribution networks must comply with the regulations on voltage, phase balance, harmonic waves, voltage flicker, and grounding mode stipulated in Articles 5, 6, 7, 8, and 10 of this Circular.

Article 42. Technical Requirements for the Control Center

1. General technical requirements

a) The monitoring, control systems, and telecommunications systems installed at the Control Center must be equipped with devices to ensure safe and reliable operation of power plants and substations managed by the Control Center;

b) The monitoring and control system of the Control Center must have compatible technical characteristics and ensure stable, reliable, and continuous data transmission from power plants and substations to the SCADA system of the Dispatching Level with control authority;

c) The Control Center must have backup power supply to ensure normal operation in case of loss of power from the national grid.

2. Connection requirements for the Control Center

a) Requirements for information system connection

- There must be two (2) independent data transmission lines connecting to the information system of the Dispatching Level with control authority. In cases where there are multiple dispatching levels with control authority, the dispatching levels must take responsibility for unifying the method of sharing information;

- There must be two (2) data transmission lines connecting to the control and information systems of power plants and substations remotely controlled by the Control Center;

- Communication means serving dispatching work, including direct communication, telephone, fax, and computer networks, must function properly.

b) Requirements for SCADA system connection

- There must be two (2) direct, simultaneous, and physically independent ports connecting to the SCADA system of the Dispatching Level with control authority. In cases where there are multiple dispatching levels with control authority, the dispatching levels must take responsibility for sharing information;

- There must be two (2) ports connecting to the RTU/Gateway terminal equipment, control systems of power plants and substations, and switching devices remotely controlled by the Control Center.

c) The Control Center must be equipped with surveillance screens and connected to security camera systems at power plants and substations to the Control Center.

3. Power plants and substations remotely controlled by the Control Center must be equipped with monitoring, control, camera, and telecommunications systems to ensure stable, reliable, and continuous data transmission and connection with the Control Center in accordance with the requirements set out in Clause 1 and Clause 2 of this Article.

Section 3

PROCEDURE AND PROCEDURES FOR CONNECTION AGREEMENTS

Article 43. Documents for Connection Request

1. In the case of connecting to a three-phase low-voltage distribution network, when there is a need for new connection or change in existing connection, the customer using the distribution network must submit to the Distribution Unit the documents specified in Appendix 2A issued together with this Circular.

2. In the case of connecting at medium voltage and 110 kV levels, when there is a need for new connection or change in existing connection, the customer using the distribution network must submit to the Distribution Unit the following documents:

a) Connection registration information corresponding to the connection needs specified in Appendices 2B, 2C, and 2D issued together with this Circular;

b) Schematic diagrams of main electrical equipment after the connection point;

c) Technical documentation on the equipment intended for connection or changes expected at the current connection point, the estimated completion time of the project, and technical data of the new connection project or changes in the current connection.

Article 44. Procedures for Negotiating Connection to Medium Voltage and 110 kV Power Supply Networks

1. Upon receiving the connection application dossier, the Distribution Unit shall be responsible for checking and notifying in writing about the completeness and validity of the dossier.

2. After receiving a complete and valid connection application dossier, the Distribution Unit shall be responsible for performing the following tasks:

a) Reviewing requirements related to the expected electrical equipment at the connection point;

b) Leading the assessment of the impact of connecting the customer's equipment, power grid, and power plant on the distribution network regarding the load-carrying capacity of existing transmission lines and substations; the impact on short-circuit current; the impact on the quality of the distribution network after connection; coordination work of protection systems;

c) Soliciting opinions from the Control Authority with control rights regarding the impact of the connection on the power system, requirements for connecting to the information system and the SCADA system of the Control Authority with control rights, requirements for relay protection, automation, and other technical requirements related to equipment at the connection point;

d) Drafting and agreeing upon a single-line diagram with technical parameters of the equipment and layout plan of the customer's power grid connected to the distribution network as the official diagram used in the Connection Agreement;

đ) Drafting the Connection Agreement according to the contents stipulated in Appendix 3 issued together with this Circular and sending it to the customer requesting connection.

3. The customer requesting connection shall be responsible for providing the Distribution Unit with necessary information for reviewing and negotiating the connection plan and signing the Connection Agreement with the Distribution Unit.

4. The Connection Agreement shall be established in five copies, each party keeping two copies and one copy sent to the Control Authority with control rights.

5. In case the connection plan cannot be agreed upon, the Distribution Unit shall notify the customer in writing and report to the Electricity Regulatory Authority about the reasons for the disagreement on the connection plan.

Article 45. Time Limit for Reviewing and Signing the Connection Agreement

1. The time limit for reviewing and signing the Connection Agreement with customers using the distribution network who request connection at 110 kV voltage level and customers owning power generation units requesting connection to the medium voltage network is specified in Table 6 as follows:

Table 6. Time Limit for Reviewing and Signing the Connection Agreement

2. For customers using electricity with their own substation connecting to the medium voltage network: Within four working days from the date of receipt of the complete and valid dossier of the customer, the Distribution Unit or the Distribution and Retail Unit shall be responsible for reviewing, negotiating, and signing the Connection Agreement with the customer using electricity with their own substation connecting to the medium voltage network.

Section 4

CONNECTION FOR CUSTOMERS

USING DISTRIBUTION NETWORK

Article 46. Access to equipment at the connection point

1. The electricity distribution unit has the right to access equipment within the customer's management scope at the connection point during construction, installation, replacement, removal, inspection, testing, maintenance, and operation of such equipment.

2. Customers using the distribution network have the right to access equipment within the management scope of the electricity distribution unit at the connection point during construction, installation, replacement, removal, inspection, testing, maintenance, and operation of such equipment.

3. The electricity distribution unit and customers using the distribution network shall be responsible for creating conditions for the parties to exercise the rights stipulated in Clause 1 and Clause 2 of this Article.

Article 47. Provision of documents for checking the conditions for energizing the connection point for customers connecting to the distribution network at 110 kV voltage level and customers with generator units connected at medium voltage level

1. Prior to the planned energization date of the connection point, the customer requesting connection must provide the electricity distribution unit with one set of documents and the control center with one set of documents for comprehensive inspection of the energization conditions of the connection point (technical documents confirmed by the customer requesting connection and certified copies of legal documents), including:

a) Partial and overall acceptance records of the connection equipment of power plants, transmission lines, and substations connected to the distribution network in compliance with Vietnamese Technical Standards (TCVN) or internationally recognized standards and meeting the technical requirements of the connection equipment specified in Section 2 of this Chapter;

b) Approved technical design documents and any modifications or supplements compared to the initial design, including the following documents:

- General description, layout plan of electrical equipment;

- Main wiring diagram, single-line diagram of the electrical system;

- Principle diagram, design of the protection and control system clearly showing circuit breakers, current transformers, voltage transformers, lightning arresters, disconnect switches, interlocked operation circuits according to the state of the circuit breaker;

- Any other related diagrams (if applicable).

c) Documents on technical parameters and operational management including the following documents:

- Technical parameters of installed equipment including those of the connection lines;

- Technical documents of excitation systems and speed regulation of generator units;

- Documents guiding the setting of protective relays and automatic devices, specialized software for communication and setting of protective relays, relay settings from the connection point towards the customer;

- Operation manuals of equipment provided by the manufacturer and any other related technical documents.

d) Planned test run schedule, energization, and operation schedule.

2. Unless otherwise agreed, the customer requesting connection shall be responsible for providing all the documents stipulated in Clause 1 of this Article within the following deadlines:

a) At least two months before the planned first trial operation of the power plant;

b) At least one month before the planned first trial operation of the transmission lines and substations (excluding the overall acceptance record of the transmission lines and substations).

3. Within no more than twenty working days from the date of receipt of complete documents for the energization of generator units or no more than fifteen working days from the date of receipt of complete documents for the energization of transmission lines and substations, the electricity distribution unit and the control center with authority to control shall be responsible for sending the following documents to the customer requesting connection:

a) Equipment numbering diagram;

b) Requirements for customer relay protection settings from the connection point towards the customer; relay setting sheets and related setting values for the customer's relay protection equipment issued or approved by the control center with authority to control;

c) Requirements for testing and calibrating equipment;

d) Requirements for dispatching command procedures;

đ) Requirements for establishing communication systems for dispatching;

e) Requirements for data collection and transmission of the SCADA system (if applicable);

g) Automatic control methods (if applicable);

h) Planned energization method;

i) List of relevant procedures related to national power system operation, distribution system operation, and coordinated operation procedures;

k) List of relevant staff members and operators along with contact phone numbers and fax numbers.

4. At least ten working days before the planned energization date of the connection point, the customer requesting connection must provide the electricity distribution unit and the control center with authority to control the following contents:

a) Test run schedule (for power plants) and energization operation schedule of electrical equipment;

b) Agreement on the division of responsibilities between both parties regarding the management and operation of connection equipment;

c) Internal regulations on safe operation of connection equipment;

d) List of customer operators including full names, professional titles, responsibilities, along with contact phone numbers and fax numbers.

Article 48. Provision of Documents for Inspection of Conditions for Energizing Connection Points for Customers with Their Own Substations Connected to Medium Voltage Grids

1. Prior to the anticipated energization date of the connection point, the customer requesting connection must provide the Distribution Unit with one set of documents for inspection of conditions for energizing the connection point (technical documents confirmed by the customer requesting connection and certified copies of legal documents), including:

a) Approved technical design documents and any amendments and supplements thereto compared to the initial design, including general descriptions, main electrical diagrams, layout plans of electrical equipment, protection and control system principle diagrams, related diagrams, and technical specifications of major electrical equipment;

b) Operation and management manuals provided by the manufacturer;

c) Partial and overall acceptance certificates of the connected equipment of the transmission line and substation to the distribution grid in compliance with Vietnamese Technical Standards (TCVN) or internationally recognized standards and meeting the technical requirements of the connected equipment as stipulated in Section 2 of this Chapter;

d) Anticipated schedule for trial energization and operation.

2. Upon receipt of all documents, the Distribution Unit shall be responsible for providing the customer requesting connection with the following documents:

a) Equipment numbering diagram;

b) Requirements for customer relay protection settings from the connection point towards the customer; relay setting sheets and related setting values for the customer's relay protection equipment issued or approved by the control center with authority to control;

c) Requirements for testing and calibrating equipment;

d) Requirements for dispatching command procedures;

đ) Requirements for establishing communication systems for dispatching;

e) Requirements for data collection and transmission of the SCADA system (if applicable);

g) Automatic control methods (if applicable);

h) Planned energization method;

i) List of relevant procedures related to national power system operation, distribution system operation, and coordinated operation procedures;

k) List of relevant staff and operators along with their contact phone numbers and fax numbers.

3. Prior to the first anticipated energization date and trial run, the customer requesting connection must provide the Distribution Unit with the following information:

a) Schedule for trial run and energization of electrical equipment;

b) Agreement on the division of responsibilities between both parties regarding the management and operation of connection equipment;

c) Internal regulations on safe operation of connection equipment;

d) List of the customer's operators including their names, professional titles, responsibilities, and contact phone numbers and fax numbers.

Article 49. Inspection of Conditions for Energizing Connection Points

1. The customer requesting connection shall be responsible for agreeing with the Distribution Unit on the actual inspection date at the connection point.

2. In case the Distribution Unit notifies that the connection point or related equipment of the customer does not meet the conditions for energization, the customer requesting connection must adjust, supplement, or replace the equipment according to the requirements and re-agree with the Distribution Unit on the time for the next inspection.

3. The Distribution Unit shall be responsible for leading and coordinating with the Control Center with authority to control regarding the sequence of inspection of conditions for energizing the connection point.

4. The Distribution Unit and the Control Center with authority to control (if any) shall sign with the customer requesting connection the Inspection Report of Conditions for Energizing the Connection Point.

Article 50. Energizing the Connection Point

1. After receiving the Inspection Report of Conditions for Energizing the Connection Point, the customer requesting connection shall be responsible for submitting to the Distribution Unit and the Control Center with authority to control the registration document for energizing the connection point along with the following documents:

a) Documents confirming that the project meets legal and technical conditions:

- Equipment within the energization scope has been tested and inspected to meet operational technical requirements and requirements at the connection point;

- Metering systems have been completed, and electricity meter readings have been sealed;

- Power purchase contracts have been signed (if applicable);

- Project acceptance documents in accordance with construction laws.

b) Documents confirming that the project meets dispatching and operational conditions:

- Primary equipment has been correctly numbered according to the primary diagram issued by the Control Center with authority to control;

- Relay protection systems have been properly adjusted according to the requirements of the Control Center with authority to control;

- Operators have been trained, examined, and granted operating certificates and recognized positions in accordance with the National Power System Dispatching Procedures issued by the Ministry of Industry and Trade;

- Dispatch communication means (direct communication channels, telephones, faxes) are functioning well;

- Full connectivity with the Supervisory Control and Data Acquisition (SCADA) system and the Control Center's information system (if applicable) has been established.

2. Within three working days from the date of receipt of the energization registration document, the Control Center with authority to control shall be responsible for leading and coordinating with the Distribution Unit to notify the customer requesting connection about the time and method of energizing the connection point.

3. The Distribution Unit and the Customer using the distribution network shall be responsible for energizing the connection point according to the method notified by the Control Center with authority to control.

Article 51. Procedures for testing and acceptance to put into operation equipment after the point of interconnection

1. For Customers using distribution networks interconnected at 110 kV voltage level and Power Generation Units with generating units interconnected at medium voltage level:

a) During the testing period to put into operation equipment after the point of interconnection, the Customer requesting interconnection must assign operating staff to be on duty and provide a list of on-duty staff along with contact phone numbers and fax numbers to the Distribution Company and Control Center with authority to coordinate operations when necessary;

b) During the acceptance trial run period, the Customer requesting interconnection shall be responsible for coordinating with the Distribution Company and Control Center with authority to ensure that operational parameters comply with technical requirements at the point of interconnection within the limits prescribed in Section 2 of this Chapter;

c) Upon completion of the acceptance trial run, the Customer requesting interconnection must confirm the actual operational parameters at the point of interconnection of electrical equipment, transmission lines, substations, and generating units. In cases where operational parameters at the point of interconnection do not meet the technical requirements stipulated in Section 2 of this Chapter due to the distribution network or electrical equipment of the Customer,

the Distribution Company has the right to disconnect the Customer's power plant or distribution network from the distribution system and request the Customer to take corrective measures;

d) The distribution network, power plant, and electrical equipment after the point of interconnection of the Customer requesting interconnection may only be officially put into operation after partial and full acceptance trial runs have been completed, meeting the technical requirements at the point of interconnection stipulated in Section 2 of this Chapter and relevant regulations under construction laws. During the acceptance trial run and official operation periods, Customers using distribution networks must comply with the National System Operation Procedures issued by the Ministry of Industry and Trade and other related regulations.

2. For Customers with their own substation interconnected to the medium voltage grid: Within six working days from the date of receiving complete valid connection point energization documents of Customers with their own substation interconnected to the medium voltage grid as prescribed in Article 48 of this Circular, the Distribution Company shall be responsible for coordinating with the Customer to complete the energization trial run, acceptance, and official energization operation for the Customer requesting interconnection.

Article 52. Inspection and supervision of operation of interconnected equipment

1. Customers using distribution networks shall be responsible for operating equipment to ensure compliance with operational technical requirements and technical requirements at the point of interconnection within the limits prescribed in this Circular. If the operational parameters of the Customer's electrical equipment do not meet the operational technical requirements and technical requirements at the point of interconnection, the Distribution Company has the right to request the Customer to re-inspect and test the equipment under the Customer's management to determine the cause and implement corrective measures.

2. In cases where both parties cannot agree on the inspection results and the cause of the violation, both parties must agree on the scope of inspection for the Customer to hire an independent testing unit to conduct re-inspection and re-testing. If the inspection results of the independent testing unit show that the violations are caused by the Customer's equipment and the Customer does not accept the corrective solutions, the Distribution Company has the right to disconnect the Customer's equipment from the distribution network.

3. Customers using distribution networks shall bear the costs of additional inspections and tests if the inspection results show that the Customer's equipment violates operational technical requirements and technical requirements at the point of interconnection. The Distribution Company shall bear the costs of additional inspections and tests if the inspection results show that the Customer's equipment does not violate operational technical requirements and technical requirements at the point of interconnection.

4. Prior to inspecting interconnected equipment to determine violations of technical requirements at the point of interconnection, the Distribution Company must notify the Customer using the distribution network and the Control Center with authority to control the inspection time and the list of inspectors. In cases where the inspection may cause power outages for the Customer, the Distribution Company must notify the Customer using the distribution network and the Control Center with authority to control at least five days in advance. Customers using distribution networks with their own substation shall be responsible for coordinating and providing all necessary conditions for the inspection work.

5. During the inspection process, the Distribution Company is permitted to install electricity metering and inspection equipment at the interconnected equipment but shall not affect the safe operation of the power plant, distribution network, and electrical equipment of the Customer using the distribution network.

6. During operation, if there is a risk of unsafe operation of the power system at the point of interconnection due to equipment owned by the Customer, the Distribution Company must immediately notify the Control Center with authority to control, the Customer using the distribution network with its own substation, and request a timeframe for corrective measures to eliminate the risk of unsafe operation of the power system. If the technical cause remains unresolved after the requested timeframe for corrective measures, the Distribution Company has the right to disconnect the point of interconnection and notify the Customer. The Customer must re-test and put into operation the equipment after the point of interconnection according to the provisions of Article 51 of this Circular.

Article 53. Replacing and Installing Additional Equipment at the Connection Point

1. In cases where customers using distribution networks with their own substations plan to replace, upgrade connection equipment, or install new electrical equipment that may affect the safe, reliable, and continuous power supply of the distribution network, the customer must notify and agree with the Distribution Unit on these changes, and the contents of the changes must be supplemented in the Connection Agreement.

2. If the proposal of customers using distribution networks with their own substations is not approved, the Distribution Unit must notify the customer in writing of any additional requirements for the new equipment planned to be changed.

3. All replaced equipment at the connection point must be inspected, tested, and accepted according to the regulations from Article 47 to Article 51 of this Circular.

Article 54. Connecting to Low Voltage Grid for Electricity Consumers

1. For electricity usage for residential purposes

Within seven working days from the date of receiving complete valid documents from the customer, the Distribution Unit or the Distribution and Retail Unit shall be responsible for signing the contract and supplying electricity to the consumer.

2. For electricity usage for non-residential purposes

a) Within three working days from the date of receiving complete valid documents from the customer, the Distribution Unit or the Distribution and Retail Unit shall be responsible for inspecting, surveying, and developing plans for supplying electricity to the requesting customer;

b) Within five working days from the date of conducting surveys and developing plans for supplying electricity, the Distribution Unit or the Distribution and Retail Unit shall be responsible for signing the contract and supplying electricity to the customer.

3. In case electricity cannot be supplied to the customer, the Distribution Unit or the Distribution and Retail Unit shall be responsible for notifying the customer, specifying the reasons and obtaining confirmation from the local Department of Industry and Trade.

Section 5

PREPARATION FOR FEEDING ELECTRICITY AT THE CONNECTION POINT FOR DISTRIBUTION UNIT'S ELECTRICAL EQUIPMENT

Article 55. Providing Documents for Inspection of Feeding Conditions at the Connection Point for Distribution Unit's Electrical Equipment

1. Prior to the scheduled feeding day at the connection point, the Distribution Unit shall be responsible for providing the Control Authority with one set of documents for inspection of feeding conditions (technical documents confirmed by the Distribution Unit and certified copies of legal documents), including:

a) Main wiring diagram, single-line diagram, layout plan of electrical equipment;

b) Principle diagrams, design of protection and control systems, clearly showing circuit breakers, current transformers, voltage transformers, lightning arresters, disconnect switches, interlocking logic circuits according to the state of circuit breakers;

c) Other related diagrams (if any);

d) Documentation guiding the setting of protective relays and automatic devices, specialized software for communication and relay settings;

đ) Technical documentation of installed equipment including parameters of the connection line;

e) Scheduled test run, feeding, and operation plan.

2. At least one month before the scheduled first trial operation of the transmission line or substation, the Distribution Unit shall be responsible for providing all documents stipulated in Clause 1 of this Article, except in cases of agreement otherwise.

3. Within fifteen working days from the date of receiving complete documents, the Control Authority shall be responsible for sending the following documents to the Distribution Unit:

a) Equipment numbering diagram;

b) Requirements regarding dispatch command reception methods;

c) Issuing relay setting sheets or approving relay setting values according to the National Power System Dispatching Procedures issued by the Ministry of Industry and Trade;

d) Requirements for testing and calibrating equipment;

đ) Requirements for establishing communication systems for dispatching;

e) Requirements for connecting and operating the SCADA system;

g) Planned method of feeding;

h) List of relevant staff and operators along with contact phone numbers and fax numbers.

4. At least seven working days before the scheduled feeding day at the connection point, the Distribution Unit must reach a consensus with the Control Authority on the schedule for test runs and operations of electrical equipment.

Article 56. Energizing the Connection Point for Electrical Equipment of the Distribution Unit

1. The distribution unit shall be responsible for sending to the Control Center with authority to control the energization registration document for the connection point along with the following documents:

a) Documents confirming that the project has completed all legal and technical procedures

- All equipment within the energization range has been tested and inspected to meet operational technical requirements and technical requirements at the connection point;

- The metering system has been completed, and the meter readings have been finalized for electricity supply and consumption;

- Project acceptance documents in accordance with construction laws.

b) Documents confirming that the project meets dispatching and operation conditions

- Primary equipment has been correctly numbered according to the primary diagram issued by the Control Center with authority to control;

- Relay protection and automatic systems have been properly adjusted according to the relay protection setting sheets issued or approved by the Control Center with authority to control;

- Operators have been trained, examined, and granted operating certificates and recognized positions in accordance with the National Power System Dispatching Procedures issued by the Ministry of Industry and Trade;

- Dispatch communication means (direct communication, telephone, fax) are functioning well;

- Information and signal connections with the SCADA system and information system of the Control Center with authority to control are fully established.

2. Within three working days from the date of receipt of the energization registration document, the Control Center with authority to control shall notify the distribution unit about the time and method of energizing the connection point.

3. The distribution unit shall coordinate with the Control Center with authority to control and other related units to energize the connection point according to the method notified by the Control Center with authority to control.

Article 57. Replacement and Installation of Additional Equipment on the Distribution Network

1. In cases where the distribution unit needs to replace, upgrade, or install additional electrical equipment on the distribution network which may affect safe, reliable, and continuous power supply of the distribution network, the distribution unit must reach an agreement in writing with the Control Center with authority to control and inform related units about these changes.

2. If the proposal of the distribution unit is not approved, the Control Center with authority to control shall notify the distribution unit of additional requirements for the new equipment planned to be changed.

3. All replacement and supplementary equipment must comply with the provisions of Articles 55 and 56 of this Circular.

Chapter 6

DISCONNECTION AND RECONNECTION OF CONNECTION POINTS

Article 58. General Provisions on Disconnection and Reconnection of Connection Points

1. Cases of disconnection include:

a) Voluntary disconnection is disconnection at the request of the customer using the distribution network, including permanent disconnection and temporary disconnection;

b) Mandatory disconnection is disconnection in cases where the customer using the distribution network violates the Connection Agreement, power purchase and sale contract, inspection and supervision regulations for connection equipment operation, or according to the requirements of the competent authority when the customer using the distribution network violates legal provisions.

2. The customer using the distribution network shall bear all costs for disconnection and reconnection.

Article 59. Voluntary Disconnection

1. Permanent disconnection

a) Cases of permanent disconnection of the customer from the distribution network and the responsibilities of the parties involved must be stipulated in the Connection Agreement and power purchase and sale contract;

b) When there is a need for permanent disconnection from the distribution network, the customer using the distribution network must notify the distribution unit and the Control Center with authority to control in writing at least one month before the scheduled permanent disconnection date. In case the customer owns generating units connected to the distribution network, they must notify the distribution unit and the Control Center with authority to control in writing at least three months before the scheduled permanent disconnection date.

2. Temporary disconnection

The customer using the distribution network shall be responsible for notifying and agreeing with the distribution unit and the Control Center with authority to control regarding the timing and duration of temporary disconnection from the distribution network.

Article 60. Mandatory Disconnection

The electricity distribution unit has the right to disconnect customers from the distribution network system in the following cases:

1. At the request for disconnection made by the competent state agency.

2. In cases of mandatory disconnection specified in the power purchase and sale contract or the Connection Agreement.

3. In the case stipulated in Clause 2 and Clause 6 of Article 52 of this Circular.

Article 61. Reconnection

The electricity distribution unit shall be responsible for reconnecting customers to the distribution network system in the following cases:

1. When there is a request for reconnection made by the competent state agency or when the reasons leading to disconnection have been eliminated, the consequences have been remedied, and all related costs have been paid by the customer.

2. When there is a request for reconnection made by the customer using the distribution network and all related costs have been paid by the customer in the case of temporary disconnection.

Chapter VI

DISTRIBUTION SYSTEM OPERATION

Section 1

RESPONSIBILITIES IN OPERATION

Article 62. Responsibilities of the Electricity Distribution Unit

1. Managing, operating, maintaining, and repairing equipment and the distribution network within its jurisdiction.

2. Preparing annual, monthly, weekly, and daily operation plans, maintenance plans, and repair plans for electrical equipment and the distribution network according to the provisions of Sections 2 and 3 of this Chapter.

3. Managing and operating the distribution network to ensure safe, stable, and reliable power supply to customers in compliance with technical operation requirements set forth in Chapter II of this Circular.

4. Investing in, installing, maintaining, managing, and operating relay protection systems within its jurisdiction to ensure stable, reliable, and selective operation. Formulating methods, calculating, and inspecting relay protection systems for the protection of customers' distribution networks at the point of connection with the distribution network if such protection schemes affect the distribution network protection system to ensure selectivity, sensitivity, and fault isolation capability.

5. Investing in, installing, maintaining, managing, and operating Distributed Control Systems (DCS), Remote Terminal Units (RTU)/Gateway devices, Supervisory Control and Data Acquisition (SCADA) systems, information systems, and communication channels within its jurisdiction to ensure reliable and continuous data transmission to the SCADA system, information system, and control system of the controlling dispatch level.

6. Adhering to the dispatch orders of the controlling dispatch level except where the execution poses a threat to human life, equipment, or the order violates established regulations.

7. Operating the distribution system in accordance with the provisions of the Transmission System Regulations, National Dispatching Procedures, National Operation Procedures, and National Fault Handling Procedures issued by the Ministry of Industry and Trade, and the provisions of this Circular.

8. Coordinating with other electricity distribution units and customers with their own substations during the operation of equipment at the point of connection with their network.

9. Coordinating with the controlling dispatch level during the preparation of distribution system operation plans, setting up protection schemes, communication information systems, SCADA data transmission, and control signals serving the operation of the distribution system.

10. Adhering to regulations on electrical safety, protection of power line safety corridors, and electrical facilities as prescribed by law.

Article 63. Responsibilities of the National Power System Dispatching Unit and Control Levels with Authority to Control

1. Develop plans and operational methods for power distribution system dispatching and operation under their control for the year, month, week, and day ahead.

2. Command and dispatch the power distribution systems under their control in accordance with the provisions set forth in the Transmission System Regulations, the National Power System Dispatching Procedures, the National Power System Incident Handling Procedures, and the National Power System Operation Procedures issued by the Ministry of Industry and Trade, as well as the regulations stipulated in this Circular, to ensure safe, stable, and reliable operation of the power distribution system.

3. Coordinate with Distribution Units and Consumers using the power distribution network in agreeing on maintenance and repair schedules for equipment; establish communication and SCADA data transmission systems and remote control systems for operation purposes; inspect and approve protection schemes within the scope of their control to ensure selectivity, sensitivity, and fault isolation capability.

4. Fulfill other responsibilities as prescribed by law.

Article 64. Responsibilities of Consumers Using the Power Distribution Network

1. Consumers connecting to medium voltage levels shall be responsible for:

a) Establishing management, operation, testing, maintenance, and repair procedures for electrical equipment and networks within their jurisdiction that comply with current laws and manufacturer specifications;

b) Managing, operating, maintaining, and repairing electrical equipment and networks within their jurisdiction to meet technical requirements specified in Section 2 Chapter V of this Circular, commitments in Connection Agreements, power purchase contracts, and current laws;

c) Adhering to dispatch orders from Control Levels with Authority to Control according to the National Power System Dispatching Procedures, National Power System Incident Handling Procedures, and National Power System Operation Procedures issued by the Ministry of Industry and Trade;

d) Providing accurate and timely information to Distribution Units to develop operational plans and maintenance and repair schedules for the power distribution system;

đ) Cooperating with Distribution Units to maintain power quality and economically operate the power distribution system as agreed upon with Distribution Units.

2. Power generation units and consumers connecting to 110 kV voltage levels shall be responsible for:

a) Implementing the provisions of Clause 1 of this Article;

b) Investing in, installing, maintaining, managing, and operating relay protection systems within their jurisdiction to ensure stable and reliable operation;

c) Investing in, installing, maintaining, managing, and operating Distributed Control Systems (DCS), Remote Terminal Units (RTU)/Gateways, information systems within their jurisdiction and communication/data transmission lines to ensure reliable and continuous data transmission to Supervisory Control and Data Acquisition (SCADA) systems, information systems, and control systems of Control Levels with Authority to Control. Without prior consent from Control Levels with Authority to Control, they may not arbitrarily disconnect related equipment from operation, which could cause SCADA signal, information signal, and control interruptions.

3. Consumers connecting to low voltage levels shall be responsible for operating their electrical equipment and networks in compliance with technical requirements specified in Section 2 Chapter V of this Circular.

Section 2

MAINTENANCE AND REPAIR PLAN FOR THE POWER DISTRIBUTION SYSTEM

Article 65. General Provisions on Maintenance and Repair of Distribution Electrical Systems

1. The distribution electricity unit shall be responsible for establishing plans for maintenance and repair of distribution electrical systems annually, monthly, and weekly to serve the planning of operation of distribution electrical systems within its management scope.

2. When establishing plans for maintenance and repair of distribution electrical systems, consideration must be given to the maintenance and repair plans for power grids and power plants of customers using distribution networks, and such plans must meet the following requirements:

a) Minimizing impact on ensuring safe, stable, reliable, and continuous power supply;

b) Optimizing coordination between maintenance and repair of power sources and power grids.

3. During the process of establishing plans for maintenance and repair of distribution electrical systems within its management scope, the distribution electricity unit shall be responsible for coordinating with control levels having control authority, transmission electricity units, and other distribution electricity units with the aim of minimizing impact on the security of power supply to the electrical system.

4. In cases where it is not possible to implement the announced plan for maintenance and repair of distribution electrical systems, customers using distribution networks with their own substations, distribution and retail electricity units shall notify and coordinate with the distribution electricity unit to adjust the plan.

Article 66. Annual Maintenance and Repair Plan

1. Before June 1st each year, customers using distribution networks with their own substations and distribution and retail electricity units shall be responsible for providing the distribution electricity unit with information about the maintenance and repair plans for the next two years for 110 kV networks and the next one year for medium voltage networks, including:

a) List of power lines and equipment related to connection points with the distribution network of the distribution electricity unit that are planned for maintenance and repair;

b) Reasons for maintenance and repair;

c) Scope of power supply interruption due to maintenance and repair work;

d) Estimated electricity consumption and load capacity of interrupted power supply;

đ) Estimated electricity generation and capacity not fed into the distribution network from power plants.

2. Before July 1st each year, the distribution electricity unit must complete the draft plan for maintenance and repair for the next two years for 110 kV networks and the next one year for medium voltage networks based on considering the following factors:

a) Results of load demand forecasting;

b) Maintenance and repair plans of customers using distribution networks with their own substations, distribution and retail electricity units, and any requests for changes to the maintenance and repair plans (if any);

c) Requirements for maintenance and repair of transmission networks;

d) Coordination of maintenance and repair plans of customers using distribution networks with their own substations, distribution and retail electricity units, in accordance with actual operating conditions to optimize technical and economic operation of the distribution electrical system;

đ) Other relevant requirements for maintenance and repair.

3. In case of disagreement with the distribution electricity unit's maintenance and repair plan, before July 10th each year, customers using distribution networks with their own substations, distribution and retail electricity units have the right to submit a written request to the distribution electricity unit to adjust the annual maintenance and repair plan. The distribution electricity unit shall be responsible for reviewing and adjusting the annual maintenance and repair plan in accordance with the customer's request. If it is not possible to adjust the maintenance and repair plan according to the customer's request, the distribution electricity unit must notify the customer in writing and provide specific reasons.

4. Before December 1st each year, the distribution electricity unit must complete and announce the plan for maintenance and repair for the next two years for 110 kV networks and the next one year for medium voltage networks on the unit’s electronic information website, including the following contents:

a) List of electrical equipment and power lines subject to maintenance and repair;

b) Reasons for taking equipment and power lines out for maintenance and repair;

c) Main content of the work;

d) Estimated time for maintenance and repair;

đ) Other relevant requirements for maintenance and repair work.

Article 67. Monthly Maintenance and Repair Plan

1. In cases where the monthly maintenance and repair plan differs from the annual maintenance and repair plan that has been published, customers using distribution networks with their own substations, and electricity distribution and retail units must provide the information specified in Clause 1, Article 66 of this Circular to the electricity distribution unit before the 10th day of each month.

2. Before the 15th day of each month, the electricity distribution unit must complete the draft of the next month's maintenance and repair plan based on the following factors:

a) The published annual maintenance and repair plan;

b) Results of the forecast for the next month's electricity demand;

c) Requests to adjust the maintenance and repair plan from customers using distribution networks with their own substations and electricity distribution and retail units;

d) Requirements for maintenance and repair on transmission networks.

3. Before the 25th day of each month, the electricity distribution unit must complete and publish the maintenance and repair plan for the next month on its website, including the following contents:

a) Names of electrical equipment and power lines subject to maintenance and repair;

b) Reasons for taking equipment and power lines out for maintenance and repair;

c) Main content of the work;

d) Expected start and end times for maintenance and repair work;

đ) Other requirements related to maintenance and repair work;

e) Estimated capacity and energy not supplied due to maintenance and repair.

Article 68. Weekly Maintenance and Repair Plan

1. Each week, the electricity distribution unit is responsible for establishing a maintenance and repair plan for the next two weeks based on the following grounds:

a) Approved monthly operation plan;

b) Results of the forecast for the next two weeks' load;

c) Updated maintenance and repair plans for power sources and networks;

d) Requests to adjust the maintenance and repair plan from customers using distribution networks with their own substations and electricity distribution and retail units.

2. In cases where there are changes compared to the monthly maintenance and repair plan, before 10:00 AM on Mondays each week, customers using distribution networks with their own substations, and electricity distribution and retail units must provide the information stipulated in Clause 1, Article 66 of this Circular to the electricity distribution unit.

3. Before 4:00 PM on Thursdays each week, based on the monthly maintenance and repair plan and the information provided by customers using distribution networks and electricity distribution and retail units, the electricity distribution unit must complete and publish the maintenance and repair plan for the next two weeks on its website, including the following contents:

a) Names of electrical equipment and power lines subject to maintenance and repair;

b) Reasons for taking equipment and power lines out for maintenance and repair;

c) Main content of the work;

d) Expected start and end times for maintenance and repair work;

đ) Other requirements related to maintenance and repair work;

e) Scope of power supply interruption due to maintenance and repair work;

g) Estimated capacity and energy not supplied due to maintenance and repair.

4. Before 4:00 PM on Fridays each week, based on the weekly maintenance and repair plan announced by the electricity distribution unit, electricity distribution and retail units are responsible for establishing a maintenance and repair plan for the distribution network within their management scope and notifying affected customers according to the regulations on conditions and procedures for interrupting or reducing power supply issued by the Ministry of Industry and Trade.

Section 3

OPERATING PLAN

Article 69. Annual Operating Plan

1. The electricity distribution unit is responsible for establishing the annual operating plan for the distribution system for the upcoming year, including the following main contents:

a) Forecast of electricity demand for the upcoming year;

b) Annual maintenance and repair plan for the upcoming year;

c) Projected generation volume for the upcoming year of power plants with installed capacity of up to 30 MW connected to the distribution network.

2. Before December 1st each year, the electricity distribution unit is responsible for completing the annual operating plan and publishing it on its website, while also informing customers using distribution networks with their own substations, electricity distribution and retail units, and relevant units about the annual operating plan for the 110 kV grid and power generating units connected to the distribution network to coordinate implementation.

Article 70. Monthly Operation Plan

1. The electricity distribution unit shall be responsible for establishing the monthly operation plan for the distribution power system based on the published annual operation plan of the distribution power system, including the following contents:

a) Forecast of electricity demand for the upcoming month;

b) Maintenance and repair plan for the upcoming month;

c) Estimated amount of electricity generation for the upcoming month from each power plant with installed capacity of 30 MW or less connected to the distribution power grid.

2. Before the 25th of each month, the electricity distribution unit shall complete the monthly operation plan and publish it on its electronic information website, while simultaneously notifying the operation plan for the medium voltage and 110 kV power grids, and power generating units connected to the distribution power grid to customers using the distribution power grid with their own substations, the distribution and retail electricity units, and related units to coordinate implementation.

Article 71. Weekly Operation Plan

1. The electricity distribution unit shall be responsible for establishing the operation plan for the distribution power system for the next two weeks based on the published monthly operation plan, including the following contents:

a) Forecast of electricity demand for the next two weeks;

b) Maintenance and repair plan for the next two weeks;

c) Estimated time and scope of power supply interruption for the next two weeks;

d) Estimated production volume and generation capacity for the next two weeks from each power plant with installed capacity of 30 MW or less connected to the distribution power grid.

2. By 16:00 on Thursday of each week, the electricity distribution unit shall complete the operation plan for the next two weeks and publish it on its electronic information website, while simultaneously notifying the operation plan for the medium voltage and 110 kV power grids, and power generating units connected to the distribution power grid to customers using the distribution power grid with their own substations, the distribution and retail electricity units, and related units to be aware and coordinate implementation.

3. By 16:00 on Friday of each week, based on the published weekly operation plan, the electricity distribution unit and the distribution and retail electricity unit shall complete the weekly operation plan for the low voltage power grid and notify affected customers within their management area.

Article 72. Daily Operation Mode

1. Every day, based on the published weekly operation plan, the electricity distribution unit shall establish the daily operation mode for the next day, including the following contents:

a) List of power sources and power grids under maintenance and repair;

b) Estimated time and scope of power supply interruption for the next day;

c) Estimated hourly production volume and generation capacity for the next day from each power plant with installed capacity of 30 MW or less connected to the distribution power grid.

2. By 16:00 every day, the electricity distribution unit shall complete and publish the daily operation mode for the next day on its electronic information website.

Article 73. Operation of the Distribution Power System

1. The electricity distribution unit shall be responsible for operating the distribution power system according to the daily operation mode and the next hour dispatch schedule that have been published, complying with the National Power System Dispatch Procedures issued by the Ministry of Industry and Trade and relevant regulations.

2. Customers using the distribution power grid shall be responsible for complying with dispatch orders from the dispatch level with authority to control, coordinate, and provide information to the electricity distribution unit to support the operation of the distribution power system.

Section 4

EMERGENCY OPERATION

Article 74. Emergency Situations

1. An emergency situation on the distribution power system is a situation where there is a total or partial blackout of the transmission power system or the distribution power system, affecting normal operation or causing widespread blackouts within the distribution power system.

2. Emergency situations include:

a) A fault or complete or partial collapse of the transmission power system affecting the normal operation of the distribution power system;

b) A fault on the transmission power system leading to a part of the distribution power system operating in an isolated island mode;

c) A fault on distribution power lines or substations supplying 110 kV voltage causing widespread blackouts within the distribution power system.

Article 75. Operation of the Distribution Power System in Case of Faults or Complete or Partial Collapse of the Transmission Power System

1. In case a fault on the transmission power system affects normal operation or causes a blackout on the distribution power grid, the Distribution Unit shall be responsible for:

a) Immediately contacting the Control Authority with authority to control and the Transmission Unit to obtain information about the expected duration of power outage and the scope of impact on the distribution power system load due to this fault;

b) Applying load control measures and other operational measures to minimize the impact scope caused by the fault on the transmission power system.

2. In case a complete or partial collapse of the transmission power system affects normal operation or causes a blackout on the distribution power system, the Distribution Unit shall be responsible for:

a) Adhering to the Black Start and National Power System Restoration Regulations and the Transmission Power System Regulations issued by the Ministry of Industry and Trade;

b) Isolating the distribution power grid under its management into separate load zones according to the National Power System Dispatch Procedures issued by the Ministry of Industry and Trade;

c) Restoring loads in priority order in accordance with the dispatch approval of the Control Authority with authority to control within its management scope;

d) Ensuring smooth communication to serve the dispatch operation of the distribution power system until the system is fully restored.

3. The Distribution Unit and large customers using the distribution power grid must ensure smooth communication, assign operational staff, and notify the relevant parties of the list (names, positions, authorities) of these staff members to coordinate operations throughout the process of handling and restoring emergency situations.

Article 76. Operation of the Distribution Power System in Case of Islanding

1. In case a part of the distribution power system is isolated, the Control Authority with authority to control must consider and decide on the operation of power plants connected to this part of the distribution power grid. The Control Authority with authority to control must direct the dispatch of power plants to operate in isolation mode and ensure readiness to synchronize with the power system upon command from higher-level dispatch.

2. In case a power plant is designed to operate independently in isolation mode and has reached agreement with the Control Authority with authority to control, the Power Generation Unit may use the self-use system to supply power to loads or customer equipment under the following conditions:

a) The power plant is equipped with sufficient protection relay systems and control methods for units both in isolation mode and when connected to the distribution power system;

b) Ensuring the ability to identify and isolate faults during isolation operation to protect the units and the distribution power grid of other customers using the isolated part of the distribution power system;

c) Ensuring the neutral grounding requirements of the isolated part of the distribution power system.

3. In case the isolated part of the distribution power system does not have the capability to synchronize with the restored part of the system, the Control Authority with authority to control must disconnect power plants connected to the isolated part of the distribution power grid to restore power supply to the isolated area from the restored system, then restore the operation of the disconnected power plants.

Article 77. Operation of the Distribution Power System in Case of Severe Incidents on the 110 kV Distribution Network

In case of incidents on transmission lines or distribution substations at 110 kV voltage level causing widespread power outages in the distribution power system, the Distribution Power Unit shall be responsible for:

1. Promptly isolating and handling the incident in accordance with the National Power System Incident Handling Procedures issued by the Ministry of Industry and Trade.

2. Notifying information about the incident to the Control Authority with control rights, the Transmission Power Unit, and customers using the distribution network with their own substations affected by the incident.

3. Changing the connection method to ensure maximum power supply capability to the distribution power system's load during the incident period.

Article 78. Restoration of the Distribution Power System

1. When the distribution power system collapses, operates in island mode, or when a major incident occurs on the distribution network, the Distribution Power Unit shall cooperate with the Control Authority with control rights, the Transmission Power Unit, customers using the distribution network with their own substations, and related units to restore the distribution power system to normal operation mode as soon as possible.

2. The Distribution Power Unit shall be responsible for dividing the load areas suitable for the black start capability of power plants and notifying the Control Authority with control rights to ensure rapid restoration of the distribution power system.

3. Power plants connected to the distribution network in island mode and synchronous operation must follow the dispatch orders of the Control Authority with control rights.

4. In cases where the distribution network does not have power plants capable of self-starting for island operation, the distribution network can only be restored from the transmission system, then the Distribution Power Unit must restore the distribution power system according to the orders of the Control Authority with control rights. The Distribution Power Unit must restore loads in priority order and according to the approved plan.

The Distribution Power Unit shall be responsible for notifying customers using the distribution network with their own substations to coordinate during the process of handling incidents to restore the distribution power system.

Section 5

LOAD CONTROL AND VOLTAGE MANAGEMENT

Article 79. Load Control

1. Load control includes measures:

a) Stopping, reducing power supply levels;

b) Shedding loads;

c) Adjusting the power consumption of customers participating in demand management programs.

2. Regulations on adjusting the power consumption of customers participating in demand management programs are implemented according to the Content and Implementation Procedures of the Load Adjustment Program issued by the Ministry of Industry and Trade.

Article 80. Stopping, Reducing Power Supply Levels

1. The Distribution Power Unit shall be responsible for implementing stopping, reducing power supply levels according to plans consistent with the weekly operation plans published as stipulated in Article 71 of this Circular.

2. The Distribution Power Unit may stop, reduce power supply levels without following plans in the following cases:

a) Due to incidents occurring on the power grid supplying customers; incidents in the power system causing power outages that the electricity supplier cannot control.

b) At the request of the National Power System Dispatch Unit when the power system lacks capacity leading to threats to the security of power supply of the national power system;

c) There is a risk of causing incidents, serious safety hazards to people, equipment, and the power system;

d) Force majeure situations.

3. When implementing stopping, reducing power supply levels, the Distribution Power Unit or the Distribution and Retail Power Unit must notify affected electricity users according to the Conditions and Procedures for Stopping, Reducing Power Supply Levels issued by the Ministry of Industry and Trade.

Article 81. Development of Load Shedding Plans

1. The electricity distribution unit shall be responsible for developing load shedding plans within its management scope based on:

a) Requirements for safe, reliable, and stable operation of the power system;

b) Load shedding plans and load regulation measures due to threats to power supply security issued by the National Power System Dispatching Unit;

c) Priority order of loads;

d) Measures to minimize impacts on customers with the same priority level of power supply.

2. The load shedding plan must include levels of capacity, order of implementation, and time of load shedding.

3. Before 16:00 every Thursday, the electricity distribution unit shall be responsible for publishing the load shedding plan for the next two weeks on the unit's electronic information page.

Article 82. Measures for Load Shedding

1. Automatic load shedding is the shedding of loads by frequency relays to selectively cut off loads in order to maintain frequency within permissible limits and prevent widespread blackouts.

2. Commanded load shedding is the shedding of loads according to the requirements of the dispatching authority with control rights in cases of insufficient power sources or incidents in the power system to ensure power supply security.

Article 83. Implementation of Load Shedding

1. The electricity distribution unit must implement load shedding according to the published load shedding plan.

2. In cases of commanded load shedding by the dispatching authority with control rights or to protect the distribution network, the electricity distribution and retail units must notify customers using electricity in accordance with the Regulations on Conditions and Procedures for Interrupting or Reducing Power Supply Levels issued by the Ministry of Industry and Trade.

3. After automatic load shedding or commanded load shedding by the dispatching authority with control rights, the electricity distribution unit shall be responsible for:

a) Notifying the dispatching authority with control rights about the capacity, time, area of loads shed, and levels of load shedding according to the set values of frequency relay actions;

b) Restoring the shed loads upon receiving orders from the dispatching authority with control rights.

4. In cases where customer-managed loads are subject to automatic load shedding or commanded load shedding by the dispatching authority with control rights, customers using the distribution network shall be responsible for:

a) Notifying the dispatching authority with control rights and the electricity distribution unit about the capacity, time, area of loads shed, and levels of load shedding according to the set values of frequency relay actions.

b) Restoring the shed loads upon receiving orders from the dispatching authority with control rights.

Article 84. Implementation of Voltage Adjustment

1. The dispatching authority with control rights and the electricity distribution unit shall be responsible for calculating and adjusting voltages at nodes on the distribution network in accordance with the National Power System Dispatching Procedures issued by the Ministry of Industry and Trade.

2. Customers using the distribution network shall be responsible for cooperating with the dispatching authority with control rights and the electricity distribution unit to maintain voltage levels on the distribution network through reactive power control measures and transformer tap adjustments.

Article 85. Remote Monitoring and Control

1. Remote control and operation of equipment at substations and power plants must comply with the National Power System Dispatching Procedures, National Power System Operation Procedures issued by the Ministry of Industry and Trade, and provisions of this Circular.

2. In cases where the electricity distribution unit or the dispatching authority with control rights requests monitoring, controlling, and remote operations of customer substations or power plants, the electricity distribution unit or the dispatching authority with control rights must reach agreement with the customer owning the substation regarding the method of monitoring and controlling the customer's equipment. The electricity distribution unit or the dispatching authority with control rights shall be responsible for equipping the control system and necessary integrated devices to collect information, monitor, and control the distribution network system of the customer owning the substation when both parties have reached an agreement, including the part of circuit breaker control according to the分级控制系统的权限分配范围内的断路器控制部分。

3. Customers owning substations who use the distribution network shall be responsible for coordinating with the electricity distribution unit and the dispatching authority with control rights in the installation and operation of remote control and monitoring systems within their management scope.

Chapter 6

INFORMATION EXCHANGE IN OPERATION AND REPORTING REGIMES

Article 86. Forms of Information Exchange

1. Electricity Distribution Units, Large Customers using Distribution Grids, and Electricity Distribution and Retail Units must agree on the forms of information exchange to ensure continuous and unobstructed communication for operational purposes 24/7.

2. Electricity Distribution Units and Large Customers using Distribution Grids and Electricity Distribution and Retail Units must designate staff responsible for operational communication, and exchange lists of such staff and operational personnel.

3. The forms of information exchange between Electricity Distribution Units, Large Customers using Distribution Grids, and Electricity Distribution and Retail Units with Control Centers having control authority must comply with the National Power System Dispatching Procedures issued by the Ministry of Industry and Trade.

Article 87. Information Exchange in Operation

1. Electricity Distribution Units and Control Centers having control authority are responsible for notifying Large Customers using Distribution Grids when distribution grid operation modes may affect their grid operation modes or generator sets, including the following information:

a) Distribution system operation modes and potential impacts on customers' grids or generator sets;

b) Causes of impact on customers' grids or generator sets and necessary remedial measures.

2. Large Customers using Distribution Grids are responsible for immediately notifying Electricity Distribution Units and Control Centers having control authority when they notice that their grid operation modes or generator sets may affect the distribution grid, including the following information:

a) Causes of changes in grid operation modes or customer generator sets;

b) Potential impacts on the distribution grid.

Article 88. Notification of Abnormal Situations

1. An abnormal situation is a situation where the distribution power system experiences an incident, a threat of an incident, or operating parameters fall outside permissible ranges.

2. When an abnormal situation occurs in the distribution power system, the Electricity Distribution Unit is responsible for:

a) Immediately notifying Large Customers using Distribution Grids that may be affected;

b) Supplementing and clarifying information provided to Large Customers using Distribution Grids that own power plants upon request.

3. Large Customers using Distribution Grids are responsible for immediately notifying the Electricity Distribution Unit when an abnormal situation occurs within their managed grid area affecting the distribution system.

Article 89. Notification of Serious Incidents

1. A serious incident is an incident leading to the disconnection of 110 kV distribution voltage transmission lines or substations from operation, causing widespread power outages in the distribution system.

2. Electricity Distribution Units and Large Customers using Distribution Grids are responsible for reporting incident information on their grids when a serious incident occurs on the grid according to the National Power System Incident Handling Procedures issued by the Ministry of Industry and Trade.

3. Notifications about serious incidents include the following main contents:

a) Time of incident occurrence;

b) Duration of incident existence;

c) Location of incident occurrence and affected areas;

d) Faulted equipment;

e) Brief description of the incident;

f) Cause of the incident (if known);

g) Anticipated time to resolve the incident;

h) Load shedding measures implemented (if any).

4. Electricity Distribution Units or Large Customers using Distribution Grids are responsible for supplementing and clarifying contents in serious incident notifications upon request.

Section 7

OPERATIONAL COORDINATION

Article 90. General responsibilities for coordinated operation

1. The electricity distribution unit and the Distribution Network Users must agree on the responsibilities and scope of control over the equipment on the distribution network related to both parties; appoint responsible persons for coordinating safe operation of the power grid and equipment.

2. The electricity distribution unit and the Distribution Network Users must cooperate, establish, and maintain necessary safety measures when performing work or testing within their respective management areas.

3. The electricity distribution unit and the Distribution Network Users must develop procedures for coordinated operation to ensure safety for personnel and equipment during operation and testing, including the following contents:

a) Nguyên tắc và các thủ tục phối hợp vận hành;

b) Trách nhiệm và quyền hạn trong việc điều khiển, vận hành và thí nghiệm

trên lưới điện phân phối trong phạm vi quản lý.

4. Đơn vị phân phối điện và Khách hàng sử dụng lưới điện phân phối có trách nhiệm thống nhất về việc phối hợp vận hành và lưu trữ, quản lý, cập nhật, trao đổi các tài liệu liên quan.

Điều 91. Phối hợp thực hiện vận hành

1. Khi thực hiện công tác, thao tác trên lưới điện, Đơn vị phân phối điện và Khách hàng sử dụng lưới điện phân phối phải tuân thủ quy định phối hợp vận hành an toàn và các quy định điều độ, vận hành an toàn khác có liên quan.

2. Đơn vị phân phối điện và Khách hàng sử dụng lưới điện phân phối có trách nhiệm phối hợp lắp đặt các biển báo, thiết bị cảnh báo và hướng dẫn an toàn, cung cấp các phương tiện phục vụ công tác phù hợp tại vị trí công tác để đảm bảo công tác an toàn.

3. Việc kiểm tra, giám sát và điều khiển thiết bị đấu nối tại ranh giới phân định tài sản phải do người được Đơn vị phân phối điện và Khách hàng sử dụng lưới điện phân phối chỉ định thực hiện.

Mục 8

THÍ NGHIỆM TRÊN HỆ THỐNG ĐIỆN PHÂN PHỐI

Điều 92. Các yêu cầu chung về thí nghiệm trên hệ thống điện phân phối

1. Thí nghiệm trên hệ thống điện phân phối bao gồm việc thí nghiệm trên lưới điện của Đơn vị phân phối điện và lưới điện, nhà máy điện hoặc thiết bị điện của Khách hàng sử dụng lưới điện phân phối.

2. Việc thí nghiệm chỉ được tiến hành trong khả năng làm việc của thiết bị điện hoặc tổ máy phát điện và trong thời gian được thông báo tiến hành thí nghiệm, có sự chứng kiến của đại diện các bên có liên quan và phải tuân thủ các quy trình, quy định hiện hành. Việc thực hiện thí nghiệm phải đảm bảo không gây nguy hiểm cho người và thiết bị trên hệ thống điện phân phối trong quá trình thí nghiệm.

3. Đơn vị phân phối điện và Khách hàng sử dụng lưới điện phân phối có trách nhiệm tổ chức thực hiện thí nghiệm định kỳ thiết bị thuộc sở hữu và quản lý vận hành để đảm bảo các thiết bị vận hành an toàn và tuân thủ các yêu cầu kỹ thuật vận hành và yêu cầu kỹ thuật tại điểm đấu nối.

4. Việc thí nghiệm thiết bị điện tại điểm đấu nối với lưới điện truyền tải phải tuân thủ Quy định hệ thống điện truyền tải do Bộ Công Thương ban hành.

5. Chi phí thí nghiệm định kỳ do đơn vị sở hữu thiết bị chi trả.

6. Chi phí thí nghiệm đột xuất do bên đề nghị thí nghiệm chi trả nếu kết quả thí nghiệm cho thấy lưới điện hoặc tổ máy phát điện đạt các yêu cầu kỹ thuật vận hành và yêu cầu kỹ thuật tại điểm đấu nối quy định tại Thông tư này hoặc các thông số ghi trong Thoả thuận đấu nối; trường hợp kết quả thí nghiệm cho thấy lưới điện hoặc tổ máy phát điện không đạt các yêu cầu kỹ thuật vận hành và yêu cầu kỹ thuật tại điểm đấu nối quy định tại Thông tư này hoặc không đúng với các thông số ghi trong Thoả thuận đấu nối thì bên sở hữu và quản lý vận hành lưới điện hoặc tổ máy phát điện không đáp ứng các yêu cầu kỹ thuật vận hành và yêu cầu kỹ thuật tại điểm đấu nối phải trả chi phí thí nghiệm.

Điều 93. Các trường hợp tiến hành thí nghiệm thiết bị trên lưới điện phân phối

1. Thí nghiệm định kỳ thiết bị trên lưới điện phân phối.

Thời hạn thí nghiệm định kỳ được thực hiện theo quy định hoặc hướng dẫn của nhà sản xuất thiết bị. Trường hợp không có quy định hoặc hướng dẫn của nhà sản xuất thì thời hạn thí nghiệm định kỳ do đơn vị sở hữu thiết bị quyết định nhưng không quá 03 năm.

Nội dung thí nghiệm định kỳ được thực hiện theo hướng dẫn của nhà sản xuất thiết bị. Trường hợp không có hướng dẫn của nhà sản xuất thì thực hiện đầy đủ các nội dung kiểm tra định kỳ được quy định tại Quy chuẩn kỹ thuật điện quốc gia do Bộ Công Thương ban hành.

2. Thí nghiệm đột xuất thiết bị trên lưới điện phân phối trong trường hợp:

a) Để đảm bảo vận hành an toàn, tin cậy và ổn định hệ thống điện phân phối;

b) Theo yêu cầu của Khách hàng sử dụng lưới điện phân phối khi có nghi ngờ chất lượng cung cấp điện trên lưới điện phân phối vi phạm các quy định tại Chương II Thông tư này hoặc cam kết trong Thỏa thuận đấu nối;

c) Theo yêu cầu của Đơn vị phân phối điện khi có nghi ngờ thiết bị của Khách hàng sử dụng lưới điện phân phối gây ảnh hưởng xấu đến lưới điện phân phối.

Điều 94. Các trường hợp tiến hành thí nghiệm tổ máy phát điện

1. Đơn vị phân phối điện có quyền thí nghiệm mỗi tổ máy phát điện đấu nối vào lưới điện phân phối không quá 02 (hai) lần trong năm, trừ các trường hợp sau:

a) Kết quả thí nghiệm xác định một hoặc nhiều đặc tính vận hành của tổ máy phát điện không đúng với các đặc tính ghi trong Thoả thuận đấu nối;

b) Khi Đơn vị phân phối điện và Đơn vị phát điện không thống nhất ý kiến về các thông số và đặc tính vận hành của tổ máy phát điện trong kết quả thí nghiệm;

c) Theo yêu cầu của Đơn vị phát điện;

d) Thí nghiệm về chuyển đổi nhiên liệu.

2. Đơn vị phát điện có quyền yêu cầu thí nghiệm trong các trường hợp sau:

a) Để kiểm tra lại các đặc tính vận hành của tổ máy phát điện đã được hiệu chỉnh sau mỗi lần xảy ra sự cố hư hỏng liên quan đến tổ máy phát điện;

b) Để kiểm tra tổ máy phát điện sau khi lắp đặt, sửa chữa lớn, thay thế, cải tiến hoặc lắp ráp lại.

Điều 95. Trách nhiệm trong thí nghiệm thiết bị trên lưới điện phân phối

1. Đơn vị phân phối điện có trách nhiệm:

a) Tổ chức thực hiện thí nghiệm định kỳ thiết bị trên lưới điện phân phối thuộc sở hữu và quản lý vận hành;

b) Tổ chức thực hiện thí nghiệm đột xuất trên lưới điện phân phối trong trường hợp cần thiết để đảm bảo lưới điện phân phối vận hành an toàn, ổn định, tin cậy và đáp ứng các yêu cầu kỹ thuật vận hành và yêu cầu kỹ thuật tại điểm đấu nối quy định tại Thông tư này;

c) Tổ chức thực hiện thí nghiệm trên lưới điện của Khách hàng sử dụng lưới điện phân phối khi có yêu cầu;

d) Phối hợp với Đơn vị truyền tải điện, Đơn vị phân phối điện khác khi tiến hành các thí nghiệm thiết bị tại các điểm đấu nối ranh giới;

đ) Thông báo trước bằng văn bản cho Khách hàng sử dụng lưới điện phân phối và các đơn vị có liên quan về kế hoạch thí nghiệm để phối hợp thực hiện.

2. Khách hàng sử dụng lưới điện phân phối có trách nhiệm:

a) Tổ chức thực hiện thí nghiệm định kỳ lưới điện, thiết bị điện, tổ máy phát điện thuộc sở hữu và quản lý vận hành;

b) Phối hợp với Đơn vị phân phối điện trong việc thí nghiệm các thiết bị điện tại điểm đấu nối với lưới điện phân phối;

c) Thông báo trước bằng văn bản cho Đơn vị phân phối điện về kế hoạch thí nghiệm để phối hợp thực hiện;

d) Tổ chức bảo dưỡng định kỳ các thiết bị điện, các thiết bị đấu nối với lưới điện phân phối;

đ) Sau khi thí nghiệm xong, gửi bản sao các biên bản thí nghiệm cho Đơn vị phân phối điện để theo dõi.

Điều 96. Trình tự thí nghiệm theo yêu cầu của Đơn vị phân phối điện

1. Khi có yêu cầu thí nghiệm thiết bị điện, tổ máy phát điện của Khách hàng sử dụng lưới điện phân phối theo quy định tại Điểm c Khoản 2 Điều 93 Thông tư này, Đơn vị phân phối điện có trách nhiệm thông báo bằng văn bản cho khách hàng ít nhất 15 ngày trước ngày dự kiến thí nghiệm. Thông báo phải bao gồm các nội dung sau:

a) Mục đích, lý do yêu cầu thí nghiệm;

b) Vị trí thí nghiệm;

c) Thời gian dự kiến thí nghiệm;

d) Hạng mục và trình tự thí nghiệm dự kiến;

đ) Kế hoạch ngừng, giảm cung cấp điện do yêu cầu của thí nghiệm (nếu có).

2. Trường hợp Khách hàng sử dụng lưới điện phân phối không nhất trí với thông báo kế hoạch thí nghiệm của Đơn vị phân phối điện, trong thời hạn 07 ngày kể từ ngày nhận được thông báo, khách hàng phải thông báo lại và đề xuất phương án giải quyết để thống nhất với Đơn vị phân phối điện về cách thức thực hiện thí nghiệm.

3. Đơn vị phân phối điện có trách nhiệm phối hợp với Khách hàng sử dụng lưới điện phân phối tổ chức thí nghiệm theo kế hoạch đã thống nhất.

4. Kết quả thí nghiệm được bên tổ chức thí nghiệm gửi cho bên còn lại.

Điều 97. Trình tự thí nghiệm theo đề nghị của Khách hàng sử dụng lưới điện phân phối

1. Thí nghiệm trên lưới điện phân phối theo quy định tại Điểm b Khoản 2 Điều 93 Thông tư này

a) Khách hàng sử dụng lưới điện phân phối phải gửi văn bản yêu cầu thí nghiệm cho Đơn vị phân phối điện, bao gồm các nội dung sau đây:

- Mục đích, lý do yêu cầu thí nghiệm;

- Hạng mục và nội dung thí nghiệm.

b) Trong thời hạn 07 ngày kể từ ngày nhận được yêu cầu thí nghiệm của Khách hàng sử dụng lưới điện phân phối, Đơn vị phân phối điện có trách nhiệm trả lời yêu cầu thí nghiệm của khách hàng;

c) Khách hàng sử dụng lưới điện phân phối và Đơn vị phân phối điện có trách nhiệm thống nhất cách thức thực hiện thí nghiệm theo yêu cầu trước khi tổ chức thí nghiệm;

d) Kết quả thí nghiệm được bên tổ chức thí nghiệm gửi cho bên còn lại.

2. Thí nghiệm lưới điện, thiết bị điện, tổ máy phát điện thuộc sở hữu và quản lý vận hành của Khách hàng sử dụng lưới điện phân phối theo đề nghị của khách hàng

a) Khách hàng sử dụng lưới điện phân phối có trách nhiệm gửi văn bản đề nghị thí nghiệm cho Đơn vị phân phối điện, bao gồm các nội dung sau:

- Mục đích, lý do đề nghị thí nghiệm;

- Vị trí thí nghiệm;

- Thời gian dự kiến thí nghiệm;

- Hạng mục và trình tự thí nghiệm dự kiến;

- Kế hoạch ngừng, giảm cung cấp điện do yêu cầu của thí nghiệm (nếu có).

b) Trường hợp thí nghiệm tổ máy phát điện, ngoài các nội dung quy định tại Điểm a Khoản này Đơn vị phát điện phải bổ sung các thông tin sau:

- Lý lịch của tổ máy phát điện;

- Các đặc tính của tổ máy phát điện;

- Dự kiến chế độ vận hành tổ máy phát điện trong thời gian thí nghiệm.

c) Trong thời hạn 07 ngày kể từ ngày nhận được đề nghị thí nghiệm của Khách hàng sử dụng lưới điện phân phối, Đơn vị phân phối điện có trách nhiệm kiểm tra và yêu cầu khách hàng bổ sung các thông tin cần thiết;

d) Trong thời hạn 14 ngày kể từ ngày nhận được đầy đủ thông tin yêu cầu thí nghiệm của Khách hàng sử dụng lưới điện phân phối, Đơn vị phân phối điện có trách nhiệm thông báo bằng văn bản cho khách hàng đề nghị thí nghiệm và các đơn vị có liên quan về kế hoạch thí nghiệm;

đ) Khách hàng sử dụng lưới điện phân phối có trách nhiệm tổ chức thực hiện thí nghiệm và gửi kết quả thí nghiệm cho Đơn vị phân phối điện.

Điều 98. Trách nhiệm thực hiện sau khi thí nghiệm

1. Đơn vị phân phối điện phải điều chỉnh, đầu tư nâng cấp, thay thế thiết bị trên lưới điện phân phối trong trường hợp kết quả thí nghiệm cho thấy thiết bị trên lưới điện phân phối thuộc sở hữu và quản lý vận hành không đáp ứng các yêu cầu kỹ thuật vận hành và yêu cầu kỹ thuật tại điểm đấu nối quy định tại Thông tư này hoặc các yêu cầu trong Thỏa thuận đấu nối.

2. Khách hàng sử dụng lưới điện phân phối phải điều chỉnh, đầu tư nâng cấp, thay thế thiết bị trong thời hạn thoả thuận với Đơn vị phân phối điện trong trường hợp kết quả thí nghiệm cho thấy thiết bị thuộc sở hữu và quản lý vận hành của khách hàng không đáp ứng các yêu cầu kỹ thuật vận hành và yêu cầu kỹ thuật tại điểm đấu nối quy định tại Thông tư này hoặc các yêu cầu trong Thỏa thuận đấu nối.

Mục 9

BÁO CÁO KẾT QUẢ VẬN HÀNH HỆ THỐNG ĐIỆN PHÂN PHỐI

Điều 99. Chế độ báo cáo

1. Báo cáo định kỳ hàng tháng

Trước ngày 10 hàng tháng, Tổng công ty Điện lực có trách nhiệm báo cáo Cục Điều tiết điện lực tình hình thực hiện, kết quả vận hành hệ thống điện phân phối của tháng trước đó bao gồm những nội dung sau:

a) Tình hình thực hiện các yêu cầu trong vận hành hệ thống điện phân phối quy định tại Chương II Thông tư này gồm:

- Yêu cầu kỹ thuật;

- Độ tin cậy cung cấp điện;

- Tổn thất điện năng;

- Chất lượng dịch vụ khách hàng.

b) Tình hình vận hành của lưới điện phân phối thuộc phạm vi quản lý: Tăng trưởng, diễn biến, dự báo phụ tải; tình hình quá tải, sự cố thiết bị và nguyên nhân xảy ra sự cố; tình hình kết nối tín hiệu SCADA, các vấn đề còn tồn tại, phát sinh trong quá trình vận hành lưới điện phân phối;

c) Đề xuất các biện pháp về vận hành, quản lý để đảm bảo vận hành lưới điện phân phối an toàn, tin cậy, nâng cao chất lượng cung cấp điện và chất lượng dịch vụ khách hàng.

2. Báo cáo định kỳ hàng năm

Trước ngày 31 tháng 01 hàng năm, Tổng công ty Điện lực có trách nhiệm báo cáo Cục Điều tiết điện lực tình hình thực hiện, kết quả vận hành hệ thống điện phân phối, bao gồm những nội dung sau:

a) Tình hình thực hiện, kết quả vận hành hệ thống điện phân phối của năm trước đó bao gồm các nội dung quy định tại Khoản 1 Điều này;

b) Kế hoạch, giải pháp về đầu tư, quản lý, vận hành, để đảm bảo vận hành lưới điện an toàn, tin cậy, nâng cao chất lượng cung cấp điện và chất lượng dịch vụ khách hàng.

3. Báo cáo đột xuất

a) Đơn vị phân phối điện có trách nhiệm báo cáo về các sự cố nghiêm trọng và ảnh hưởng do ngừng giảm cung cấp điện tới Khách hàng sử dụng điện và các Đơn vị phân phối và bán lẻ điện mua điện của Đơn vị phân phối điện bằng văn bản cho Cục Điều tiết điện lực, Sở Công Thương theo Quy định điều kiện trình tự ngừng, giảm mức cung cấp điện do Bộ Công Thương ban hành;

b) Đơn vị phân phối điện có trách nhiệm báo cáo đột xuất tình hình vận hành hệ thống điện phân phối theo yêu cầu của Cục Điều tiết điện lực, Sở Công Thương, Tập đoàn Điện lực Việt Nam, Đơn vị điều độ hệ thống điện quốc gia.

Chương VII

TỔ CHỨC THỰC HIỆN

Điều 100. Tổ chức thực hiện

1. Cục Điều tiết điện lực có trách nhiệm phổ biến, hướng dẫn và kiểm tra việc thực hiện Thông tư này.

2. Trường hợp cần thiết, Cục Điều tiết điện lực có trách nhiệm tổ chức xây dựng và ban hành Quy trình hướng dẫn chi tiết về yêu cầu kỹ thuật đối với hệ thống điện mặt trời, hệ thống điện gió đấu nối vào lưới điện phân phối phù hợp với các quy định tại Thông tư này.

3. Tập đoàn Điện lực Việt Nam có trách nhiệm chỉ đạo các đơn vị thành viên thực hiện Thông tư này.

4. Đơn vị phân phối điện và Khách hàng sử dụng lưới điện phân phối có trách nhiệm xây dựng kế hoạch để đầu tư, nâng cấp và cải tạo lưới điện, thiết bị điện trong phạm vi quản lý đảm bảo đáp ứng các yêu cầu kỹ thuật quy định tại Thông tư này.

5. Trong quá trình thực hiện, nếu xảy ra tranh chấp giữa các đơn vị liên quan đến việc thực hiện Thông tư này, các đơn vị có quyền trình vụ việc lên Cục Điều tiết điện lực để giải quyết theo quy định về trình tự, thủ tục giải quyết tranh chấp trong hoạt động điện lực do Bộ Công Thương ban hành.

Điều 101. Sửa đổi một số Điều của Thông tư số 12/2010/TT-BCT ngày 15 tháng 4 năm 2010 của Bộ trưởng Bộ Công Thương quy định hệ thống điện truyền tải và Thông tư số 40/2014/TT-BCT ngày 05 tháng 11 năm 2014 của Bộ trưởng Bộ Công Thương quy định quy trình điều độ hệ thống điện quốc gia

1. Sửa đổi Khoản 2 Điều 3 Thông tư số 12/2010/TT-BCT như sau:

“2. Cấp điện áp là một trong những giá trị của điện áp danh định được sử dụng trong hệ thống điện, bao gồm:

a) Hạ áp là cấp điện áp danh định đến 1000 V;

b) Trung áp là cấp điện áp danh định trên 1000 V đến 35 kV;

c) Cao áp là cấp điện áp danh định trên 35 kV đến 220 kV;

d) Siêu cao áp là cấp điện áp danh định trên 220 kV.”.

2. Sửa đổi Khoản 33 Điều 3 Thông tư số 12/2010/TT-BCT như sau:

“33. Lưới điện phân phối là phần lưới điện bao gồm các đường dây và trạm điện có cấp điện áp đến 110 kV.”.

3. Sửa đổi Khoản 34 Điều 3 Thông tư số 12/2010/TT-BCT như sau:

“34. Lưới điện truyền tải là phần lưới điện bao gồm các đường dây và trạm điện có cấp điện áp trên 110 kV.”.

4. Sửa đổi Khoản 35 Điều 3 Thông tư số 40/2014/TT-BCT như sau:

“35. Lưới điện trung áp là lưới điện phân phối có cấp điện áp danh định trên 1000 V đến 35 kV.”.

Điều 102. Hiệu lực thi hành

1. Thông tư này có hiệu lực kể từ ngày 18 tháng 01 năm 2016. Thông tư số 32/2010/TT-BCT ngày 30 tháng 7 năm 2010 của Bộ trưởng Bộ Công Thương quy định hệ thống điện phân phối hết hiệu lực từ ngày Thông tư này có hiệu lực.

2. Trường hợp đã có hợp đồng mua sắm, lắp đặt thiết bị được ký trước ngày 15 tháng 9 năm 2010 mà có nội dung khác với quy định tại Thông tư này, Đơn vị phân phối điện và Khách hàng sử dụng lưới điện phân phối được tiếp tục thực hiện theo hợp đồng đã ký.

3. Trong quá trình thực hiện Thông tư này, nếu có vấn đề vướng mắc, yêu cầu các đơn vị có liên quan phản ánh trực tiếp về Cục Điều tiết điện lực để xem xét, giải quyết theo thẩm quyền hoặc báo cáo Bộ Công Thương để giải quyết./.