Decision No. 16/2007/QĐ-BCN On the Issuance of the National Power System Operation Procedures

Pursuant to …;

Regarding the issuance of the National Power System Operation Procedures

___________________________

THE MINISTER OF INDUSTRY

Pursuant to Decree No. 55/2003/NĐ-CP dated May 28, 2003 of the Government stipulating the functions, tasks, powers, and organizational structure of the Ministry of Industry;

WHEREAS pursuant to the Electricity Law dated December 3, 2004;

Pursuant to Decree No. 105/2005/NĐ-CP dated August 17, 2005 of the Government detailing and guiding the implementation of certain provisions of the Electricity Law;

On the proposal of the Director of the Electricity Regulatory Authority and the Head of the Legal Department,

DECISION:

Article 1. The attached Decision promulgates the "National Power System Operation Procedures".

Article 2. The procedures issued with this Decision replace the National Power System Operation Procedures issued under Decision No. 90/NL-KHKT dated February 22, 1994 of the Minister of Energy. This Decision shall take effect fifteen days from the date of publication in the Official Gazette.

Article 3. The Heads of the Office of the Ministry, the Inspectorate of the Ministry, Heads of Departments, Directors of Bureaus under the Ministry, Provincial Industrial Departments of centrally governed cities, Vietnam Electricity Corporation, and organizations and individuals engaged in electricity activities are responsible for implementing this Decision./.

PROCEDURE

NATIONAL POWER SYSTEM OPERATIONS
(Issued together with Decision No. 16/2007/QĐ-BCN dated March 28, 2007 of the Minister of Industry)

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PART I

GENERAL PROVISIONS

Article 1These procedures specify the principles and operations in operating electrical equipment of power plants and substations, and power grids at 1 kV and above in normal conditions. In emergency conditions, the operation of electrical equipment of power plants and substations shall be carried out according to the National Power System Emergency Procedures issued under Decision No... dated... of the Minister of Industry.

Article 2. These procedures apply to all levels of dispatching, organizations, and individuals participating in electricity activities and using electricity on the territory of Vietnam that have electrical equipment or power grids connected to the national power system. In cases of cross-border electricity trade, the operation of connecting devices shall be conducted according to the dispatching agreements signed between both parties.

Based on these procedures, all levels of dispatching, organizations, and individuals participating in electricity activities and using electricity on the territory of Vietnam shall compile their own operational regulations considering the electrical diagram characteristics, technical characteristics of the equipment, and manufacturer's specifications.

Article 3. Definitions

1. Normal condition refers to the basic wiring configuration according to the determined operating mode, where all parameters of the equipment in operation within the national power system are within permissible limits.

2. DCS is an integrated control system installed at power plants or substations.

3. Dispatcher is the person directly commanding the distribution system dispatching.

4. Operating management unit is the entity owning, managing, and operating equipment connected to the national power system, including: power generation units, transmission units, and distribution units.

5. Peak hour is the period of maximum electricity demand.

Peak day hours: From 9:30 am to 11:30 am;

Peak evening hours:

From April 16 to October 15: From 6:00 pm to 8:00 pm;

From October 16 to April 15: From 5:00 pm to 7:00 pm.

6. GIS is a gas-insulated substation (insulated by SF6 gas or oil pressure).

7. National power system is a network of power generation facilities, power grids, and auxiliary equipment interconnected and uniformly commanded within the country's scope, under the control and inspection of the national-level dispatching authority.

8. Regional power system is a power system located in the North, Central, or South regions with voltage up to 220 kV, under the control and inspection of the regional-level dispatching authority.

9. Distribution system is a power system with voltage up to 35 kV under the control of the distribution-level dispatching authority.

10. National power system operator is the engineer who directly commands the national power system dispatching.

11. Regional power system operator is the engineer who directly commands the regional power system dispatching.

12. Operation command is the request to perform an operation aimed at dispatching purposes.

13. Command issuer is the person authorized to control the equipment or the person delegated to control the equipment according to the hierarchical dispatching authority of the national power system as stipulated in the National Power System Dispatching Procedures issued with Decision No. 56/2001/QĐ-BCN of the Minister of Industry dated November 26, 2001.

14. Command receiver is the subordinate operating staff directly under the command issuer.

15. Operating staff are those directly involved in controlling the production, transmission, and distribution processes of electricity, including: national power system operators; dispatchers; shift leaders of power plants; crew leaders or main duty personnel at substations.

16. Static stability is the ability of the power system to recover its initial state or very close to it after small disturbances (in cases where disturbances cannot be eliminated).

17. Dynamic stability is the ability of the power system to recover its initial state or near its initial state after large disturbances (permissible operating state).

18. RTU is the terminal device of the supervisory control and data acquisition system (located at substations or power plants).

19. SCADA is the supervisory control and data acquisition system (located at the dispatch center).

20. Incident is an unwanted event occurring in the power system affecting safe, continuous, stable, and quality operation of the power system.

21. Operation is the activity of changing the status of one or more devices in the power system with the purpose of changing the operating mode of that element.

21. Substation is a transformer station, switchgear station, or compensation station.

Chapter II

ORGANIZATION OF OPERATIONS

Mục 1: OPERATING ORDERS

Article 4. Operating orders are directly transmitted from the issuer to the recipient through communication systems. In special cases where communication is lost, operating orders may be relayed through on-duty operators at other units. In such cases, the operator receiving the order must fully record it in the logbook and make an audio recording, and promptly transmit the operating order to the correct recipient.

Article 5When transmitting orders, the issuer must clearly state their name and must identify the name and position of the recipient. Operating orders must be fully recorded and audio recorded.

Article 6. Operating orders must be concise, clear, and accurate, specifying the purpose of the operation and the sequence of actions. Both the issuer and the recipient must understand the sequence of all planned operational steps, the conditions allowing execution based on actual system diagrams, and equipment operating modes.

Article 7. If there is a possibility of losing contact with mobile operators, orders can be issued to these personnel before they perform multiple tasks simultaneously, while agreeing on the time for operations, but the clock must be synchronized with the issuer's clock. Operations are prohibited if the scheduled time is incorrect.

Article 8. The recipient of the operating order must repeat the entire order, fully record the operation sequence, the name of the issuer, and the time requested for the operation. Only when the issuer confirms that everything is correct and permits the operation can the recipient proceed. Upon completion, the end time must be recorded and reported back to the issuer.

If the recipient does not fully understand the operating order, they have the right to request clarification from the issuer and only proceed once the order is understood.

Article 9. An operating order is considered completed when the recipient reports the results to the issuer or if the scheduled time has passed.

Mục 2: OPERATING TICKET

Article 10. All operations must be documented on an operating ticket prior to execution, except in the following cases:

1. Handling emergencies. In this case, the operator must fully record each step of the emergency handling process in the operation logbook;

2. At dispatch levels, simple operations consisting of no more than three steps. In this case, the issuer must fully record each step of the operation in the operation logbook before executing the operation;

3. Following a standard operating ticket as specified in Article 16 of this procedure. In this case, the operator must verify that the standard operating ticket matches the current grid diagram.

Operating tickets are prepared according to the prescribed forms, including Form 01-PTT/BCN and regulations applied in Appendix 2; Form 02-PTT/BCN and regulations applied in Appendix 3.

Article 11. Preparation and approval of operating tickets according to plan

1. At the national power system dispatch level and regional power system dispatch level: Operating tickets are prepared by the method officer; approved by the director or deputy director or authorized person by the director.

2. At distribution system dispatch levels: Operating tickets are prepared by the method officer; approved by the head or deputy head of the dispatch level or assigned person by the power company leadership.

3. At power companies or district power branches: Operating tickets are prepared by technical staff; approved by the branch head or deputy head or assigned person by the power company leadership.

4. At power plants: Operating tickets are prepared by the main duty officer; approved by the shift leader, section leader, or assigned person by the plant leadership.

5. At substations: Operating tickets are prepared by the main duty officer; approved by the substation head or deputy head.

Article 12. Preparation and approval of emergency operating tickets

At dispatch levels: Operating tickets are prepared and approved by the system operation engineer or on-duty dispatcher.

At power plants or substations: Operating tickets are prepared and approved by the direct equipment operator and reviewed by the higher-level operator.

Article 13For operations limited to a single substation or power plant, the issuer may delegate the recipient to prepare the operating ticket, which must then be approved by the issuer.

Article 14. Operating tickets must be clear and not altered or erased. The operating ticket must specify which wiring diagram it applies to. Before performing the operation, the actual wiring diagram must correspond to the one in the ticket; if it does not match, a new ticket consistent with the actual diagram must be prepared. Any changes to the operation content in the ticket to align with the actual diagram must be agreed upon by the approver, recorded in the "Abnormal Events During Operation" section, and the operation logbook.

Article 15. All prepared operating tickets must be numbered. Completed operating tickets must be stored for at least three months. Operating tickets must be kept in the investigation file if an incident or accident occurs during the operation.

Article 16. Standard operating tickets are prepared for the following situations:

Disconnecting or putting into operation a busbar;

Using a bypass circuit breaker instead of an operating circuit breaker and vice versa;

Disconnecting or putting into operation a transformer;

Disconnecting or putting into operation compensation devices;

Disconnecting or putting into operation a transmission line.

Operating tickets are prepared by dispatch levels or equipment management units but must be approved by the issuer before the operation.

Section 3: IMPLEMENTATION OF OPERATIONS

Article 17. Relationships during operations between dispatching staff at various levels and lower-level operating staff shall be governed by the National Power System Dispatching Procedures issued together with Decision No. 56/2001/QĐ-BCN of the Minister of Industry on November 26, 2001. Relationships during operations among staff within the same unit shall follow the provisions of that unit.

The person performing the operation must implement safety measures according to the current Electrical Safety Technical Procedures.

Article 18. Before issuing operation commands, the issuer must pay attention to the following contents:

1. Name of the operation ticket and purpose of the operation;

2. Start time and end time of the operation;

3. Current wiring diagram of the power system, regional grid, or plant/substation where the operation will take place;

4. Operating status of switching devices. Operating status and operational principles of protective relays, automatic equipment, arc suppression coils, neutral grounding points, measuring, control, and remote signaling devices;

5. Permanently grounded elements;

6. Forecast changes in power and voltage in the power system after the operation and must have appropriate adjustment measures to avoid overload, low voltage, or overvoltage according to voltage regulation regulations;

7. Communication dispatching system diagram, SCADA system diagram, especially in cases where operations affect the operation mode of the communication and SCADA systems;

8. Supply sources and self-use system diagrams;

9. Safety measures for personnel and equipment, other relevant notes related to the operation;

10. The issuer is ultimately responsible for the operation ticket, must read the operation ticket carefully, identify unreasonable points, and sign the operation ticket before issuing the operation command.

Article 19. When implementing the operation ticket, the staff receiving the operation command must pay attention to the following contents:

Carefully read the operation ticket and check whether the operation ticket is consistent with the purpose of the operation;

If there are any unreasonable or unclear items in the operation ticket, they must request the issuer to clarify. Only proceed with the operation when all steps are clearly understood;

The recipient of the operation command must sign and write their full name on the operation ticket before performing the operation;

Before conducting the operation, verify the actual wiring diagram to ensure it matches the operation ticket;

All operations must be carried out strictly in accordance with the sequence specified in the operation ticket. Unauthorized changes to the sequence are not allowed without permission from the issuer;

After completing each step of the operation, mark each operation on the ticket to prevent confusion and omission of items;

During the operation, if warnings appear or equipment malfunctions occur, or abnormal phenomena arise, investigate the cause before proceeding with subsequent operations;

All remote-controlled isolator switch or grounding switch operations must immediately check the on-site status after each operation. For GIS substations, mechanical signals indicating the on-site status of the isolator switch or grounding switch must be checked. Operation procedures for circuit breakers and isolator switches see Sections 1 and 2 of Chapter III of this procedure.

Article 20. Limit operations during peak hours and shift change times. Operations are only permitted during these times in case of emergencies or threats to personnel or equipment safety, causing load restrictions or reducing system stability.

If an operation starts before the shift change and continues into the shift change period, the previous shift staff must select appropriate operation items to stop reasonably. In complex operations, the previous shift staff must remain to complete all operation items, and shift change is only allowed with the direct unit leader's consent. The direct unit leader permitting shift change in such cases bears full responsibility for their decision.

Article 21. All operations must be performed by two people: one supervisor and one operator. Both must be familiar with the site equipment diagrams and positions; trained and certified for their roles; assigned to operate directly. The operator must have a safety level of at least Level 3, while the supervisor must have a safety level of at least Level 4. In all cases, both bear equal responsibility for the operation.

Article 22. The sequence for performing operations according to the operation ticket is as follows:

At the operation or control position, the operator must carefully check again to ensure the names of the equipment match those on the operation ticket;

Once the correct equipment to be operated is confirmed, the supervisor reads, the operator repeats, and performs each step of the operation according to the operation ticket.

Article 23. For complex operations such as energizing or testing new equipment, they must be carried out according to the approved method, with coordination with relevant departments and corresponding dispatch levels, specifying the person responsible for the entire operation process and the tasks listed in the program.

Article 24. After completing the operation, the operator must perform handover procedures for the equipment according to regulations, fully documenting the operation ticket name, relay protection and automatic device wiring diagram changes, placement or removal of portable grounding devices with clear locations, wiring diagram changes, ongoing or completed work teams in the operation log and shift handover book.

Article 25. Before putting equipment or lines back into operation after maintenance, the operator must confirm that all work units (personnel and tools) have been completely withdrawn, all portable grounding devices removed, and all work tickets locked out.

Article 26During the operation of primary equipment, the operator must promptly carry out necessary operations on protective relays and automatic equipment in accordance with the unit's procedures for operating such equipment.

If the transformer with grounded neutral is disconnected from operation, it is necessary to check the grounding system that has been specified for that facility or the local power grid.

When equipment is taken out for repair and creates a situation where the current transformer is located between two earthed points, to prevent the differential protection of the busbar from incorrectly operating during testing, the circuit of that current transformer must be separated from the differential protection of the busbar before closing the earthing switch and conducting the test.

Article 27. It is prohibited to perform energization operations on transmission lines or equipment when all primary protections are not functioning.

Article 28. The interlocking circuit (logic circuit) is equipped to prevent incorrect operations by the operator. In case an operation of the circuit breaker or isolator cannot be performed, the operator must stop the operation to check:

1. Whether the operation was correct or not;

2. Whether the position of the equipment related to the ongoing operations matches the interlocking circuit;

3. Whether the interlocking circuit is functioning properly. If the inspection results show any faults in the interlocking circuit, they must be immediately reported to the person who issued the operation command;

4. Operators are not allowed to disconnect or isolate the interlocking circuits arbitrarily. Any changes to the interlocking circuits must be regulated and approved by the direct unit leader or higher-level operators.

Chapter III

BASIC OPERATIONS

Section 1: OPERATIONS ON CIRCUIT BREAKERS

Article 29. General provisions for circuit breakers

1) Circuit breakers are permitted to close and interrupt loads and short circuits within their rated capacity.

2) Circuit breakers must be checked to meet the requirements for closing and interrupting before performing operations.

3) Circuit breakers need to be inspected and maintained (according to the circuit breaker operation procedures or the manufacturer's instructions) under the following circumstances:

a) Having interrupted the total short-circuit current up to the specified limit;

b) Having reached the specified number of short-circuit interruptions;

c) Having reached the specified number of closing and tripping operations;

d) Having operated for the specified duration.

4. Before putting a circuit breaker in service from standby mode, it must be rechecked along with related components to ensure normal operation of the circuit breaker.

Article 30. Performing operations on circuit breakers is only allowed when the control circuit is in good condition and not grounded. Operations in the event of a ground fault in the control circuit are only allowed in emergency conditions.

Article 31. After any circuit breaker operation, it is necessary to check the local status indicator of the circuit breaker, and lock the control circuit of the circuit breaker if subsequent local operations on both sides of the isolators of this circuit breaker are to be performed.

The open state of the associated circuit breaker must be checked before moving from the operational state to the test state or vice versa.

Article 32. Testing operations on circuit breakers can be carried out when one of the following conditions is met:

Both side isolators of the circuit breaker are fully opened, and only the earth switch or mobile earth switch is closed on one side of this circuit breaker.

If one side isolator of the circuit breaker is closed, all earth connections in the compartment of this circuit breaker must be removed.

Article 33. Checking the status of the circuit breaker based on signal light indications and measuring instruments without checking the local status indicator is allowed in the following cases:

After the circuit breaker operation, there is no operation on both side isolators of the circuit breaker;

After the circuit breaker operation, the operation on both side isolators of the circuit breaker is performed remotely (from the central control room);

Remote operation is performed.

Article 34. Circuit breakers that have interrupted the total short-circuit current or reached the specified number of short-circuit interruptions but are still required for additional fault interruption, after being checked to meet the operational standards and obtaining approval from the director or deputy director of technical management of the equipment operation unit, may be allowed to interrupt additional faults.

Section 2: OPERATIONS OF DISCONNECTING SWITCHES

Article 35. Disconnecting switches may be operated without power or with power when the operating current is less than the allowable operating current according to the operation procedures of the disconnecting switch issued by the operation management unit. Disconnecting switches may be used to perform live operations in the following cases:

Closing and opening the neutral point of transformers and reactors;

Closing and opening arc suppression coils when there is no ground fault in the power grid;

Closing and opening transfer bars when circuit breakers or disconnecting switches connecting the busbar have been closed;

Closing and opening unloaded busbars or conductor sections;

Closing and opening bypass disconnecting switches;

Closing and opening unloaded voltage transformers and current transformers;

Unloaded closing and opening of power transformers, overhead lines, and cables must be permitted by the equipment operation management unit depending on each type of disconnecting switch.

Mechanical or automatic drive mechanisms of disconnecting switches used for breaking magnetic currents, charging currents, load currents, and balancing currents must ensure rapid travel and decisive operation.

Article 36. Before performing disconnecting switch operations on both sides of the circuit breaker, it is necessary to check that the circuit breaker has successfully opened all three phases, and lock the circuit breaker control if the disconnecting switch is operated locally.

Article 37. Local disconnecting switch operations must be performed quickly and decisively, but should not be forcefully struck at the end of the travel. During the closing (or opening) of the disconnecting switch, it is strictly prohibited to open (or close) the blade again upon seeing an arc.

Article 38. After completing the disconnecting switch operation, it is necessary to check the position of the blades to prevent incomplete travel, causing the blade to slide out of the static contact.

Section 3: OPERATIONS OF ELECTRICAL EQUIPMENT

Article 39. Separation or synchronization operations of generators and compensators; switching operations of reactors and capacitors; tap-changing operations of transformers and related operations must be carried out according to the operation procedures of each power plant or substation. For system operators or dispatchers, before performing separation or synchronization operations of generators; switching operations of reactors and capacitors; tap-changing operations of transformers, it is necessary to recheck the system operation mode.

Article 40. The sequence of operations to remove transformers for maintenance is as follows:

Check power flow, mobilize power sources, or make appropriate grid connections to avoid overloading other transformers or related transmission lines;

Switch to self-use power supply if the self-use power supply is taken from this transformer;

Lock the automatic voltage regulation under load (if available);

Open circuit breakers on the low-voltage, medium-voltage, and high-voltage sides of the transformer in the prescribed order (open the load side first, then the source side);

Check that the transformer has no residual voltage;

Open relevant disconnecting switches on the low-voltage, medium-voltage, and high-voltage sides of the transformer in the prescribed order;

Open the excitation transformers of the voltage transformers of the transformer (if available);

Close fixed grounding switches on the low-voltage, medium-voltage, and high-voltage sides of the transformer;

The operation management unit implements safety measures and hangs warning signs according to the current Electrical Safety Technical Procedures;

Hand over the transformer to the work unit, while reminding and emphasizing the work unit about safety.

Article 41. The sequence of operations to put transformers back into service after maintenance is as follows:

The operation management unit hands over the transformer that has completed maintenance work, with all personnel and tools withdrawn, all portable grounding removed, and the transformer meeting operational standards and ready for energization;

Remove all fixed grounding switches on all sides of the transformer;

Close the excitation transformers of the voltage transformers of the transformer (if available);

Check that the protection systems and cooling systems of the transformer have been put into operation;

Set the tap changer to the appropriate position to avoid overvoltage when energizing the transformer;

Close relevant disconnecting switches on the low-voltage, medium-voltage, and high-voltage sides of the transformer;

Close the circuit breaker on the power source side of the transformer, then sequentially close the remaining circuit breakers;

Switch to self-use power supply (if necessary);

After putting the transformer back into service, check its operational status. Depending on the operational mode, the automatic tap changer regulation mode can be put into operation.

Article 42. When closing or opening unloaded transformers with partially insulated neutral points (with neutral grounding disconnecting switches), it is necessary to note that the neutral point must be grounded beforehand, regardless of whether there is lightning protection at the neutral point. After energizing the transformer, it is necessary to return its neutral point to normal operation according to the usual operational mode.

Section 4: OPERATIONS ON THE LINE

Article 43. Operations on a single-source line shall be carried out in the following sequence:

1. Disconnecting a line with circuit breakers and isolating switches at both ends for repair:

a) Open the line circuit breaker;

b) Check that the three-phase circuit breaker has been fully opened;

c) Open the isolating switch on the line side;

d) Open the isolating switch on the busbar side (if necessary);

đ) Close the grounding switches on the line;

e) Hand over the line to the operating units for work, noting that they must take their own safety measures and hang warning signs according to the current Electrical Safety Technical Procedures.

2. Putting a line with circuit breakers and isolating switches at both ends back into operation:

a) The operating units hand over the line to the operating units after repairs when all personnel and equipment have been withdrawn, all portable grounding devices have been removed, the line meets operational standards, and is ready to be energized;

b) Open the grounding switches on the line;

c) Check that the three-phase circuit breaker has been fully opened;

d) Close the isolating switch on the busbar side (if it is open);

đ) Close the isolating switch on the line side;

e) Close the line circuit breaker.

3. Disconnecting a line with a combined circuit breaker for repair:

a) Open the line circuit breaker;

b) Check that the three-phase circuit breaker has been fully opened;

c) Move the circuit breaker out of the operating position;

d) Close the grounding switches on the line;

đ) Hand over the line to the operating units for work, noting that they must take their own safety measures and hang warning signs according to the current Electrical Safety Technical Procedures.

4. Putting a line with a combined circuit breaker back into operation:

a) The operating units hand over the line to the operating units after repairs when all personnel and equipment have been withdrawn, all portable grounding devices have been removed, the line meets operational standards, and is ready to be energized;

b) Open the grounding switches on the line;

c) Check that the three-phase circuit breaker has been fully opened;

d) Move the circuit breaker into the operating position;

đ) Close the line circuit breaker.

Article 44. On lines with branch substations, before performing operations on the line, the total load of the branch substations must be sequentially disconnected if the total load of the branch substations is ≥ 10 MW.

Article 45. Operations on a line supplied from two sides and without branches shall follow the following sequence:

1. Disconnecting the line for repair:

a) Check the power flow and voltage of the system before performing the operation. Adjust the power and voltage, transfer loads appropriately to avoid overload and excessive voltage during the operation;

b) Open the circuit breakers at both ends of the line in the prescribed sequence;

c) Open the isolating switch on the line side and the isolating switch on the busbar side (if necessary) of the second circuit breaker;

d) Open the isolating switch on the line side and the isolating switch on the busbar side of the first circuit breaker;

đ) Close the grounding switch on the first end;

e) Close the grounding switch on the second end;

g) Hand over the line to the operating units for work, noting that they must take their own safety measures and hang warning signs according to the current Electrical Safety Technical Procedures.

2. Putting the line back into operation after repair:

a) The operating units hand over the line when all personnel and equipment have been withdrawn, all portable grounding devices have been removed, the line meets operational standards, and is ready to be energized;

b) Open the grounding switch on the first end;

c) Open the grounding switch on the second end;

d) Close the isolating switch on the busbar side (if it is open) and the isolating switch on the line side of the second circuit breaker;

đ) Close the isolating switch on the busbar side (if it is open) and the isolating switch on the line side of the first circuit breaker;

e) Close the circuit breakers at both ends of the line in the prescribed sequence;

g) Re-adjust the power and voltage, transfer loads appropriately after putting the line back into operation.

Article 46. Operations on a line with multiple sources and branch substations shall follow the following sequence:

1. Disconnecting the line for repair:

a) Check the power flow and voltage of the system before performing the operation. Adjust the power and voltage, transfer all loads from branch substations not receiving power from this line;

b) Sequentially disconnect all circuit breakers of the branch substations and the supply substations, and all isolating switches of the branch substations and the supply substations in the correct sequence as prescribed;

c) Close the grounding switches on the line at all substations connected to this line;

d) Hand over the line to the operating units for work, noting that they must take their own safety measures and hang warning signs according to the current Electrical Safety Technical Procedures.

2. Putting the line back into operation after repair:

a) The operating units hand over the line: all personnel and equipment have been withdrawn, all portable grounding devices have been removed, the line meets operational standards, and is ready to be energized;

b) Open all grounding switches on the line;

c) Sequentially close all isolating switches of the branch substations and the supply substations, and all circuit breakers of the branch substations and the supply substations in the correct sequence as prescribed;

d) Re-adjust the power and voltage, transfer loads appropriately after putting the line back into operation.

Article 48. Overhead power lines operating in closed circuit without load from a single source or in standby mode must have the isolating switch on the line side of the open circuit breakers opened.

Article 48. Power lines that have been de-energized and safety measures completed may be handed over to the working unit.

When handing over power lines to the repair unit, the handover content must be in the following form:

The power line (specify name and circuit) has been de-energized, at the points (specify station or plant name) where grounding wires have been installed at which positions. Allow safety measures to be taken so that the working unit can start work;

The time when the work must be completed;

If it is a two-circuit power line, it must specify whether the other circuit is energized and take necessary measures to prevent induced voltage;

Other relevant notes related to the work.

Article 49. If the power line repair work involves repairing equipment related to the power line at the substation or power plant under the dispatch control, coordination between operation management units to develop repair plans, resolve work registration for operation management units, and notify the relevant units of the repair plan is required.

Strictly prohibit operation personnel from cutting grounded wires or removing warning signs without an order from the person issuing the operation command.

If due to work conditions, it is necessary to cut fixed grounding wires on the power line while there are still workers on the line, then other grounding wires or portable grounding wires must be installed before cutting these grounding wires. After completing the work, the fixed grounding wires must be reinstalled before removing the portable grounding wires.

Article 50. Operation personnel, after performing the power-off operation on the power line and related equipment at the substation or power plant for repair, must operate the steps on the schematic diagram as recorded in the work permit and hang warning signs and grounding symbols fully (if not equipped with SCADA). Record the operation time and permission to work in the operation logbook. In the work permit and operation logbook, clearly record the number of grounding wires installed, the number of participating repair units, and other noteworthy characteristics.

Article 51. After completing the repair work on the power line and related equipment at the substation or power plant, the operation management unit must confirm that all personnel and equipment have been withdrawn, all portable grounding wires have been removed, and return the power line and blocking equipment of the substation or power plant to the dispatch control for the order to restore power.

The content of the report to return the power line is as follows: "Work on the power line (name of power line and circuit), on the equipment (name of outgoing circuit equipment at the substation or power plant) according to work permit (number) has been completed, all portable grounding wires at the site have been removed, all personnel from the working units have withdrawn; the power line and equipment meet operational standards and are ready to receive power; request to return the power line and equipment for restoration of power."

Article 52. If during the power-off of the power line, measures such as primary rewiring, secondary rewiring... (as recorded in the operation logbook) were implemented, then when restoring power to this line, the operation personnel of the dispatch control level must perform primary rewiring, secondary rewiring to match the new schematic diagram and must record it in the operation logbook.

Section 5: OPERATIONS WITH RESERVE BUSES

Article 53. Operations to put reserve buses into operation must pay attention to:

Checking that the reserve bus has no mobile grounding, disconnecting all fixed groundings.

Must use a circuit breaker with protective relays to test the reserve bus. If there is no circuit breaker for testing the reserve bus, select an appropriate circuit breaker at the connection point to discharge the reserve bus. In cases where a circuit breaker cannot be selected for testing the reserve bus, check the insulation of that bus (possibly using a megohmmeter) before using a disconnector to close the bus.

Article 54. Before performing operations to switch the connection point from one bus to another, attention must be paid to:

Checking the differential protection of the bus, isolating the differential protection of the bus (if necessary) according to the regulations of the operating management unit.

Checking the two circuit breakers or disconnectors connected to both buses that are closed. Disconnect the control circuit of the circuit breaker if the disconnector operation is performed on-site during the disconnector operation to switch the connection point.

Monitoring changes in power flow and current through the circuit breaker. Selecting a reasonable sequence of operations to switch the connection point from one bus to another to avoid overloading the circuit breaker.

The operating management unit must prepare a sample operation ticket applicable for bus switching operations. This sample operation ticket clearly records the first and second priority sequences of operations corresponding to the primary and secondary diagrams of the substation.

Article 55. At substations equipped with loop circuit breakers, the operating management unit must prepare a sample operation ticket applicable for operations using a loop circuit breaker instead of another circuit breaker and vice versa. This sample operation ticket clearly records the first and second priority sequences of operations corresponding to the primary and secondary diagrams of the substation.

Section 6: LOOP CIRCUIT CLOSURE, LOOP CIRCUIT SEPARATION, SYNCHRONIZATION, NETWORK SEPARATION

Article 56. A loop circuit can only be closed in the electrical system when it is confirmed that the phase angle and phase sequence are identical at the loop closure point. At each dispatch level, a list of possible loop closure points must be approved by the dispatch leadership.

Article 57. Before performing loop circuit closure or separation operations, or before performing operations to connect or disconnect interconnection lines, voltage adjustment must be made so that the voltage difference between the two sides of the synchronization point is less than the allowable value specified in Article 58 of this procedure, and attention must be paid to the operation of relay protection and automatic devices, changes in power flow and voltage in the electrical system.

Article 58. Under normal operating conditions, synchronization operations must be performed at circuit breakers equipped with synchronous devices.

Conditions for synchronization on the 500 kV power system:

a) Phase angle difference of voltage between the two sides of the synchronization point: d £ 15⁰;

b) Frequency difference between the two sides of the synchronization point: Df £ 0.05 Hz;

c) Voltage difference between the two sides of the synchronization point: DU £ 5%.

Conditions for synchronization on the power system with voltage levels £ 220 kV:

a) Phase angle difference of voltage between the two sides of the synchronization point: d £ 30⁰;

b) Frequency difference between the two sides of the synchronization point: Df £ 0.25 Hz;

c) Voltage difference between the two sides of the synchronization point: DU £ 10%.

Article 59. When performing operations to disconnect the transmission line connecting the power plant to the power system, separate the loop circuit, or separate the power systems for independent operation, all dispatch levels must coordinate to adjust the power between power plants or balance the power of the power systems so as to maintain the normal operating condition of the power systems.

Section 7: OPERATIONS TO PUT NEW EQUIPMENT AND LINES INTO SERVICE

Article 60. The procedures for putting new equipment and lines into service shall be carried out in accordance with the regulations on putting new projects into operation as stipulated in the National Power System Dispatching Procedures.

Article 61. Prior to the first energization of new equipment, the following conditions must be noted:

The equipment has been tested and meets operational standards;

Relay protection systems, cooling systems, fire prevention systems, and other related systems are ready to operate;

Relay protection has been set according to the requirements for energizing new equipment;

The acceptance committee has signed the decision to energize or synchronize the new equipment;

Grid configuration changes (if feasible) must ensure safety during the first energization of new equipment.

In the case of energizing new circuit breakers:

a) Create a method using the circuit breaker (with protection) to energize the new circuit breaker. For example, in a two-busbar system with a tiebreaker: Create a method using the tiebreaker to de-energize the new circuit breaker;

b) If it is not possible to create a method using the circuit breaker to energize the new circuit breaker, only the isolator switch on the busbar side may be used to energize the new circuit breaker, provided that this isolator switch is controlled from the control room or remotely;

c) In the case of energizing a new transformer: After energizing unloaded from one side, the correct phase sequence and phase position must be checked on the remaining sides;

d) In the case of synchronizing a generator for the first time: Automatic synchronization (the automatic synchronization device has been tested and meets operational standards) must be performed.

The sequence of operations for energizing or synchronizing new equipment shall follow the procedure or operation ticket approved by the competent authorities.

Article 62. Prior to the first energization of new lines, the following conditions must be noted:

The line has been accepted and meets operational standards;

Relay protection has been set according to the requirements for energizing the new line;

The acceptance committee has signed the decision to energize the new line;

After energizing unloaded from one end, the correct phase sequence and phase position must be checked on the remaining ends before closing the loop or synchronizing two systems.

The sequence of operations for energizing new lines shall follow the procedure or operation ticket approved by the competent authorities.

Section 8: REMOTE OPERATIONS

Article 63. Responsibilities of the Ministry of Science and Technology Remote operations must be conducted by the power system operator engineer or dispatcher directly controlling electrical equipment at substations or power plants through the SCADA system.

Article 64. Remote operations may only be carried out when the following conditions are met:

The communication system is functioning properly;

The RTU (or DCS) is functioning properly;

The control lockout status at the substation is set to allow remote operation from the dispatch level;

The SCADA system at the dispatch center is functioning properly;

There is a test report ensuring that remote operations function correctly and reliably.

Article 65. All remote operations must be carried out in accordance with the operation tickets specified in Section 2 of Chapter II of this Procedure, and the basic operations specified in Chapter III of this Procedure.

Article 66. Conducting remote operations at substations or power plants:

At substations or power plants where there are operating staff on duty, the power system operator engineer or dispatcher must instruct subordinate operating staff to check the actual status of circuit breakers and isolators after each remote operation step if necessary for the safety of subsequent steps.

At substations or power plants without regular staff on duty:

a) In planned operations, the operating management unit must assign operating staff to be present at the station before carrying out the operation;

b) In unplanned remote operations and when there is no operating staff present at the station, remote operations are only allowed for circuit breakers; for isolators, remote operations are only permitted in emergency situations.

Chapter IV

NUMBERING OF EQUIPMENT IN THE NATIONAL POWER SYSTEM

Section 1: GENERAL PRINCIPLES

Article 67. At power plants, substations, and major equipment, auxiliary equipment must be named and numbered. Major equipment must be numbered according to regulations, while auxiliary equipment must be numbered sequentially based on the major equipment and additional characters must be added to distinguish them.

Article 68. In Section 2 of this Chapter, only the principles for numbering primary electrical equipment at power plants and substations under the control of dispatch levels are specified. Operating management units shall independently define the numbering of equipment under their own control.

Article 69. The numbering of primary electrical equipment at power plants and substations under the control of dispatch levels is regulated as follows:

All equipment put into operation in the national power system must be named and numbered. Equipment within the national power system under the control of which dispatch level shall be numbered and approved by that dispatch level.

Numbering of equipment under the control of one dispatch level but subject to inspection by another dispatch level can only be issued with the consent of the dispatch level responsible for inspection.

For some substations with special diagrams, numbering of equipment shall also be based on this regulation, with special cases clearly noted.

This numbering regulation applies to new projects. Projects currently in operation that do not comply with this regulation must be renumbered when conditions permit.

Section 2: NUMBERING OF EQUIPMENT IN THE POWER SYSTEM

Article 70. Digits representing voltage levels

1. 500 kV voltage: Take digit 5

2. 220 kV voltage: Take digit 2

3. 110 kV voltage: Take digit 1

4. 66 kV voltage: Take digit 7

5. 35 kV voltage: Take digit 3

6. 22 kV voltage: Take digit 4

7. 15 kV voltage: Take digit 8 (except for generator terminal voltage and synchronous compensator terminal voltage / 15 kV, both take digit 9)

8. 10 kV voltage: Take digit 9 (generator terminal voltage and synchronous compensator terminal voltage / 10 kV both take digit 9)

9. 6 kV voltage: Take digit 6 (generator terminal voltage and synchronous compensator terminal voltage less than 10 kV both take digit 6)

10. Other voltage levels shall be self-defined by the dispatch level with control authority and must be approved by the dispatch level responsible for inspection.

Article 71. Name of busbar

The first character shall be the letter C.

The second character indicates the voltage level, according to the provisions of Article 70 of this Procedure.

The third character indicates the sequence number of the busbar, with the number 9 representing a ring busbar.

Example:

- C12: represents the second busbar at 110 kV voltage level;

- C21: represents the first busbar at 220 kV voltage level;

- C29: represents the ring busbar at 220 kV voltage level.

Article 72. Name of generator or synchronous compensator

1.)The first character is defined as follows:

a) For thermal power plants using steam: The symbol is the letter S;

b) For hydroelectric power plants: The symbol is the letter H;

c) For gas turbines: The symbol is the letter GT;

d) For exhaust steam turbines: The symbol is the letter ST;

đ) For diesel engines: The symbol is the letter D;

e) For synchronous compensators: The symbol is the letter B.

The subsequent character is the sequence number of the generator.

Example:

S1: represents the first thermal power plant unit.

GT2: represents the second gas turbine unit.

Article 73. Name of transformer

1.)The first character is defined as follows:

a) For two-winding or three-winding transformers: The symbol is the letter T;

b) For auto-transformers: The symbol is AT;

c) For self-used transformers: The symbol is TD;

d) For excitation transformers for generators: The symbol is TE;

đ) For neutral grounding transformers: The symbol is TT.

2.The subsequent character is the sequence number of the transformer. For self-used transformers, the subsequent character is the voltage level and the sequence number.

Example:

T1: represents the first transformer.

T2: represents the second transformer.

TD41: represents the first self-used transformer at 22 kV voltage level.

AT1: represents the first auto-transformer.

Article 74. Name of circuit breaker

1.)The first character specifies the voltage level, as provided in Article 70 of this Procedure. For capacitors' circuit breakers, the first character is the letter T, and for reactors, it is the letter K, with the second character specifying the voltage level.

2.)The second character (third for reactor and capacitor circuit breakers) specifies the position of the circuit breaker, defined as follows:

a) Transformer circuit breaker: Use the number 3.

b) Line circuit breaker: Use the numbers 7 and 8 (or from 5 to 8 if the diagram is complex).

c) Self-used transformer circuit breaker: Use the number 4.

d) Generator end circuit breaker: Use the number 0.

đ) Synchronous compensator circuit breaker: Use the number 0.

e) Shunt capacitor circuit breaker: Use the number 0.

g) Series capacitor circuit breaker: Use the number 0 (or 9 if the diagram is complex).

h) Reactor circuit breaker: Use the number 0 (or 9 if the diagram is complex).

3.)The third character (fourth for reactor and capacitor circuit breakers) indicates the sequence number: 1, 2, 3...

4.)For circuit breakers on a double-ring busbar, the next character after the first is: 00.

5.)For interconnecting circuit breakers between two busbars, the next two characters after the first are the numbers of the two busbars:

a) For a two-busbar scheme (or a single busbar with sections), even-numbered circuit breakers on even-numbered busbars are given even sequence numbers, and odd-numbered circuit breakers on odd-numbered busbars are given odd sequence numbers.

b) For a polygonal scheme, circuit breakers are numbered according to the line circuit breakers.

c) For a 3/2 (one and a half) scheme, a 4/3 scheme: Depending on the scheme, they can be numbered as follows:

- Numbering circuit breakers according to line circuit breakers;

- Numbering the second character of the circuit breaker in the middle (not connected to the busbar) as 5 or 6.

- Numbering the third character according to the bay sequence.

Example:

371: represents the first 35 kV line circuit breaker.

131: represents the first transformer circuit breaker at 110 kV voltage level.

641: represents the first self-used transformer circuit breaker at 6 kV voltage level.

903: represents the third generator end circuit breaker at 10 kV voltage level.

K504: represents the fourth reactor circuit breaker on the busbar at 500 kV voltage level.

100: represents the ring circuit breaker at 110 kV voltage level.

212: represents the interconnecting circuit breaker between two busbars at 220 kV voltage level.

Article 75. Name of Reactor

The first two characters are the letters KH, except for the neutral reactor which is marked KT.

The third character represents the voltage level, following the provisions set out in Article 70 of this Procedure.

The fourth character is the number 0.

The fifth character is the sequence number of the circuit where the reactor is connected.

Example:

KH504: Represents a reactor at 500 kV connected to circuit number four.

KT303: Represents a neutral reactor at 35 kV connected to the neutral of transformer number three.

Article 76. Name of Capacitor

1. The first three characters: For series capacitors, use TBD; for parallel capacitors, use TBN.

2. The fourth character represents the voltage level, following the provisions set out in Article 70 of this Procedure.

3. The fifth character is the number 0.

4. The sixth character is the sequence number of the circuit where the capacitor is connected, for series capacitors, and the sequence number of the capacitor bank for parallel capacitors.

Example:

TBD501: Represents a series capacitor at 500 kV connected to circuit number one.

TBN302: Represents a parallel capacitor at 35 kV connected to circuit number two.

Article 77. Name of Voltage Transformers

The first character is TU;

Subsequent characters take the name of the equipment to which the voltage transformer is connected. For equipment whose name does not clearly indicate the voltage level, after the first two characters, there will be a character representing the voltage level, followed by the name of the equipment.

Example:

TU171: Represents a voltage transformer on the 110 kV transmission line 171.

TUC22: Represents a voltage transformer for busbar 220 kV number two.

TU5T2: Represents a voltage transformer for the 500 kV side of transformer T2.

Article 78. Name of Current Transformers

The first two characters are TI;

Subsequent characters take the name of the equipment to which the current transformer is connected. For equipment whose name does not clearly indicate the voltage level, after the first two characters, there will be a character representing the voltage level, followed by the name of the equipment.

Example:

TI171: Represents a current transformer at 110 kV connected to circuit breaker 171.

Article 79. Name of Neutral Resistors Connected to the Neutral Point of Transformers or Reactors

The initial characters are RT indicating a neutral resistor;

The next character represents the voltage level;

The subsequent character is the name of the equipment to which RT is connected.

Example:

RT1T1: Represents a neutral resistor connected to the neutral of the 110 kV winding of transformer T1.

Article 80. Name of Lightning Arresters

The first two characters are CS;

The next character takes the name of the protected equipment. For equipment whose name does not clearly indicate the voltage level, after the first two characters, there will be a character representing the voltage level, followed by the name of the equipment. For lightning arresters connected to the neutral of transformers at the voltage level, use the number 0.

Example:

CS1T1: Represents a lightning arrester for transformer T1 at 110 kV.

CS0T1: Represents a lightning arrester connected to the neutral of transformer T1.

CS271: Represents a lightning arrester for line 271.

Article 81. Name of Isolators

1. The initial characters are the name of the circuit breaker or directly connected equipment (for isolators of TU, the initial characters are the name of TU, followed by the name of the directly connected equipment), followed by a separator (-).

2. The subsequent character is defined as follows:

a) For isolators of busbars, use the sequence number of the busbar connected to the isolator;

b) For isolators of transmission lines (isolators on the transmission line side), use the number 7;

c) For isolators connected to transformers, use the number 3;

d) For isolators connected to loop busbars, use the number 9;

e) For isolators connected to bypass a device, use the number 0 or 9;

f) For isolators connected to a specific busbar section (on the busbar section side), use the sequence number of that busbar section;

g) For isolators connected to neutral resistors or neutral reactors, use the number 0.

Example:

331-3: Represents an isolator of transformer T1 at 35 kV.

K501-1: Represents an isolator of reactor number 1 at 500 kV connected to busbar number 1.

TUC22-2: Represents an isolator of the voltage transformer for busbar 220 kV number two connected to busbar number 2.

171-7: Represents an isolator outside the 110 kV transmission line of circuit breaker 171.

272-9: Represents an isolator of circuit breaker 272 connected to the loop busbar.

275-0: Represents an isolator bypassing circuit breaker 275.

KT301-0: Represents an isolator of the neutral of transformer T1 at 35 kV connected to neutral reactor KT301.

Article 82. Name of fuses

The first characters: For general fuses, use the letters CC; for self-falling fuses, use the letters FCO.

The next character is a separator (-) followed by the name of the protected device.

Example:

CC-TUC31: indicates the fuse of the high-voltage transformer phase C31.

Article 83. Name of grounding switches

The first characters are the name of the isolating switch or directly related equipment.

The next character specifies the grounding, defined as follows:

a) Grounding of transmission lines and capacitors uses the number 6;

b) Grounding of transformers, reactors, and TUs uses the number 8;

c) Grounding of circuit breakers uses the number 5;

d) Grounding of phases uses the number 4;

e) Grounding of the neutral point of transformers or reactors uses the number 08.

Example:

271-76: indicates the external line grounding switch 271.

331-38: indicates the grounding switch of transformer T1 on the 35 kV side.

171-15: indicates the grounding switch of circuit breaker 171 on the side of isolating switch 171-1.

131-08: indicates the neutral point grounding switch of the 110 kV winding of transformer number 1.

Article 84. Switchgear at branch points and segments between lines are marked as follows:

For sectionalizing circuit breakers on lines, they are numbered like line circuit breakers; for branch circuit breakers leading to transformers, they are numbered like transformer circuit breakers.

For sectionalizing isolators or branch isolators, the first characters are numbered according to Article 81 (isolator numbering assumes the presence of a circuit breaker).

The final characters are a separator (/) and the position of the sectionalizing pole or branch point.

Example:

371/XX: indicates the sectionalizing circuit breaker 371 on pole number XX at 35 kV voltage level.

171-7/XX: indicates the sectionalizing isolator on the 110 kV line at pole number XX.

171-76/XX: indicates the grounding isolator on the 110 kV line at pole number XX.

Article 85. The appendices accompanying this procedure include:

1. Appendix 1 specifies abbreviations used in operation tickets;

2. Appendix 2 provides guidance on implementing model operation ticket 01-PTT/BCN;

3. Appendix 3 provides guidance on implementing model operation ticket 02-PTT/BCN./.