Working position: Main circuit isolation contacts \ Secondary plug reliable contact;

Testing position: Main circuit isolation contacts are disconnected, but the secondary plug is in a reliable contact state;

Maintenance position: Both the main circuit isolation contacts and the secondary plug are disconnected.

A. Switch

Operating state: The handcart is in the working position, the switch is closed, and the protection device is enabled (the reclosing device is disabled or enabled as per dispatch requirements).

Hot standby state: The handcart is in the working position, the switch is open, and the protection device is enabled (the reclosing device is disabled as per dispatch requirements);

Cold standby state: The handcart is in the testing position, the switch is open, and the protection device is disabled (the reclosing device is disabled as per dispatch requirements);

Maintenance state: The handcart is in the maintenance position, the switch is open, the fuses of the switch operation circuit and closing circuit are removed, and safety measures are arranged according to the maintenance work ticket.

B. Voltage transformer, lightning arrester

Operating state: The handcart is in the working position.

Hot standby state: (No such state).

Cold standby state: The voltage transformer handcart is in the testing position, and the lightning arrester handcart is in the maintenance position.

Maintenance state: The handcart is in the maintenance position, and safety measures are arranged according to the maintenance work ticket.

Operating state: Refers to the relevant knife switches and switches being in the closed position, and the reclosing device being in the disabled or enabled position as per dispatch requirements.

Hot standby state: Refers to the switch being open while the relevant knife switches are still in the closed position, and the reclosing device is disabled.

Cold standby state: Refers to the switch and all side knife switches being in the open position, the reclosing device is disabled, and the fuses of the switch operation circuit and closing circuit are removed.

Maintenance state: Refers to the switch being in the cold standby state, the switch energy is released, the power fuses are removed, the secondary circuit of the bus differential current transformer is short-circuited to ground, and safety measures are arranged according to the maintenance work ticket;

Operating state: Refers to any switch of the equipment (lines, main transformers, bypass connections, interconnections, etc.) on the bus being in the operating state.

Hot standby state: (No such state for the bus)

Cold standby state: Refers to the switches of the equipment on the bus being in the cold standby state. Additionally, if there are no dispatch requirements, the lightning arresters and voltage transformers that can be disconnected by knife switches and are not under maintenance are also included in the cold standby state of the bus.

Maintenance state: Refers to the switches of the equipment on the bus being in the cold standby or maintenance state, and the lightning arresters and voltage transformers that can be disconnected by knife switches should also be in the cold standby or maintenance state, with safety measures arranged according to the work ticket.

Operating state: Refers to the knife switch on the high voltage side being in the closed position.

Hot standby state: (No such state).

Cold standby state: Refers to the knife switch on the high voltage side being in the open position, and the low voltage side fuses being removed.

Maintenance state: Refers to being in the cold standby state, and safety measures are arranged according to the maintenance work ticket.

Operating state: Refers to the relevant knife switches and switches on either side of the (main) transformer being in the closed position.

Hot standby state: Refers to the switches on either side of the (main) transformer being open while the knife switches are still in the closed position.

Cold standby state: Refers to the switches and knife switches on either side of the (main) transformer being in the open position, but does not include the neutral point grounding knife switch.

Maintenance state: The (main) transformer is in the cold standby state, and safety measures are arranged according to the work ticket.

Switching operations are an important task for electrical operation personnel. During the switching operation process, it is necessary to strictly follow the relevant regulations and the five systems of switching operations, namely the operation ticket system, command verification system, diagram rehearsal system, supervision and counting repetition system, and inspection reporting system.

A. General requirements for filling out operation tickets:

1) Each operation ticket is only allowed to fill out one operation task, and whoever operates fills it out.

2) Operation tickets are required to use dispatch terminology, and the equipment names in the operation task column should use dual numbering.

3) Two or more operations must fill out operation tickets, with clear handwriting. If there are corrections, they must not exceed three characters, and the correction must be signed by the duty supervisor.

4) Operation tickets should be filled out item by item according to the drawings or simulation screens that match the actual site, and must not be combined. The open and closed positions of circuit breakers and isolating switches should be filled out separately.

5) The operation ticket filled out by the operator should be reviewed and approved by the supervisor, and both parties should sign it. It can only be operated after being re-examined and approved by the duty supervisor.

6) The inspection items for switching operations can be filled out as one item, while the inspection items for circuit breakers and other equipment must be listed separately.

7) Operation tickets must not use ellipses, "same as above" and other terms.

8) The start, end, and reporting times of operations, important equipment start and stop times, release and connection times, and the times for protection and automatic devices to be put in or out should be recorded accurately and completely.

9) Operation tickets that have been executed should be stamped with "Executed"; those not executed should be stamped with "Not Executed"; and those voided should be stamped with "Voided".

10) The operation tickets that have been executed should be checked by the station master once a month, the pass rate should be counted, and they should be kept for six months.

B. The items that must be filled in the operation ticket are:

1) Pulling the circuit breaker and isolating switch and their inspection items;

2) Installing and removing grounding wires and their inspection items;

3) Checking load distribution and verifying that there is no voltage;

4) Putting on or taking off control circuit and voltage circuit fuses;

5) Engaging or disengaging automatic devices and protection circuit pressure plates.

1) After the guardian receives the high-level command, they should recite it back to the issuer according to the tasks in the operation ticket. After both parties confirm it is correct, they should immediately fill in the issuing time and issuer in the operation ticket.

2) For single operations, after the guardian receives the dispatch command, they should immediately fill it in the duty record and recite it back to the issuer based on the filled record. After both parties confirm it is correct, they should conduct a board drill. Then operate according to the duty record.

3) When the dispatch issues and verifies commands, both parties should have a recording.

1) After all preparations are ready, the operator and guardian should first simulate the operation on a system simulation diagram according to the order listed in the operation ticket, and verify the correctness of the operation ticket again.

2) The guardian should call out each item listed in the operation ticket, and the operator should recite it back while simulating the operation on the diagram.

3) After the first system simulation diagram drill, a comprehensive check should be conducted to ensure the operation mode of the modified simulation diagram is correct and without issues.

4) After the simulation drill, if the operation ticket is confirmed to be correct, the operator should seek approval from the duty supervisor before proceeding with the switching operation.

1) The guardian should carry the equipment key, and the operator should bring the operating tools. Upon arriving at the operation site, they should jointly check that the equipment's position, name, and number match the operation ticket.

2) The guardian should unlock the equipment, call out each item in the order listed in the operation ticket, and the operator should point to the equipment number while reciting it back. The calling out and recitation must be serious, clear, and loud. The guardian can only give the order "Correct, execute" after confirming the operator's recitation is correct, and the operator can only operate after hearing this command.

3) After completing each operation, the guardian should check the quality and mark "√" in the sequence number before that item.

1) In addition to checking each operation item, a comprehensive check should be conducted after all operations are completed, paying attention to the equipment status and instrument changes.

2) After the operation is completed, a comprehensive check should also be conducted on all operation items in the operation ticket to prevent omissions.

3) After all operations are completed and checked without errors, the operator should immediately report the completion of the operation and the end time to the dispatcher, and stamp "Executed" on the operation ticket.

4) After the operation is completed, the guardian should promptly report the completion of the operation task and the end time to the on-duty dispatcher and make a record on the relevant records of the operation task.

5) After completing an operation task, an evaluation of the executed operation should be conducted to summarize experiences for continuous improvement of operational skills.

Precautions for operations under accident conditions:

1) In case of an accident, operations can be conducted without an operation ticket, but records should be kept.

2) Accident handling can proceed with the approval of superiors to lift the lockout.

3) When there is a risk to personal and equipment safety, the power can be disconnected first, but the dispatcher should be informed immediately afterward.

A voltage tester is a safety tool used to check whether electrical equipment is truly de-energized. It tests the equipment's electrification through sound and light generated by contact with the live part.

The following precautions must be observed when using a high-voltage voltage tester:

1) A qualified voltage tester with a rated voltage consistent with the voltage level of the tested equipment must be used.

2) Insulated gloves must be worn when testing on high-voltage equipment.

3) When using, extend the tester's rod to the allowed safe distance, and the operator should hold the part below the protective ring of the tester, not exceeding the protective ring. Gradually approach the tested equipment; when sound and light are emitted, it indicates the equipment is live; otherwise, it is de-energized.

4) Before testing on de-energized equipment, a test should be conducted on a live equipment of the same voltage level to confirm the tester is functioning properly, then proceed to test the working equipment phase by phase, and immediately ground it after confirming there is no voltage (if grounding is needed).

5) When using the voltage tester, the upper metal part of the tester (working part) should be regarded as a live part, and it should not be touched or approached simultaneously with adjacent phases or grounded parts.

6) When there is residual charge on the cable circuit or capacitor, the sound and light indicator will emit a brief weak sound and light, then stop automatically.

7) After each use, the tester's rod should be retracted, and the surface should be cleaned before placing it back in its packaging and storing it in a fixed location.

8) The voltage tester must undergo regular testing every six months and be recorded.

9) Voltage testers that exceed the testing cycle are prohibited from use.

The following precautions must be observed when using a low-voltage voltage tester:

1) When using, hold the voltage pen with one hand and touch the metal part at the top of the pen with one finger, while the metal tip of the pen contacts the tested part.

2) The low-voltage voltage pen must be tested in a known live area before use to prove that the voltage pen is indeed functioning normally.

3) The low-voltage voltage pen can only be used below 500V and is prohibited for use on high-voltage circuits.

4) During testing, prevent causing phase-to-phase short circuits to avoid arc burns.