Chassis Truck Operation Guide for Medium and High-Voltage Switchgear

The safe and correct operation of the chassis truck is a critical task in medium and high-voltage switchgear, directly impacting the stability of the power grid and the safety of on-site personnel. The chassis truck carries the withdrawable type circuit breaker and other key electrical components, facilitating the connection or isolation of the main circuit through precise insertion and withdrawal. This is a highly professional procedure where every step must be executed with precision to ensure equipment reliability and a zero-risk environment for operators. This guide provides a comprehensive overview of switchgear chassis truck operation, covering three main phases: preparation, execution, and post-operation inspection.

1. Pre-Operation Preparation

Thorough preparation is the first step to ensuring a safe and successful operation of chassis truck. Operators must strictly follow safety regulations and undertake rigorous preparation.

• Tool and Equipment Inspection:
  • Tool Preparation: Inspect all necessary tools and equipment for the operation, including, but not limited to, the operating handle, grounding switch operating rod, high-voltage detector, etc. Ensure they are in good condition and free of damage.
  • Personal Protective Equipment (PPE): All personal protective equipment, including insulated gloves, insulated boots, and a safety helmet, must be worn. Ensure this equipment is certified and effective in protecting the operator.
• Power-Off Verification:
  • Systemic Power-Off: Before beginning the operation, you must use multiple methods to ensure both the main circuit and auxiliary circuit of the switchgear are completely de-energized.
  • Switch Status Confirmation: Verify that the main vacuum circuit breaker is in the “open” position, and its mechanical indicator and control panel lights both confirm this status.
  • Multi-Level Verification: Use a high-voltage detector for a secondary check to confirm there is no voltage inside the switchgear.
  • Grounding: Complete the necessary grounding procedures to ensure equipment is safe.
• Interlocks and Work Area:
  • Interlock Check: Check that all mechanical and electrical switchgear interlock are functioning correctly to effectively prevent misoperation.
  • Area Clearance: Clear the chassis truck operation area, removing all obstacles and debris to ensure smooth movement.

2. Chassis Truck Operation Procedures

Chassis truck operation must be performed with caution and precision. This process typically involves moving the VCB chassis truck from the “service” position to the “test” position, and from the “test” position to the “maintenance” position.

• Opening and Closing the Circuit Breaker:
  • Closing (Connecting the Main Circuit): Insert the chassis truck’s handle into the circuit breaker operating hole. Press and hold the handle’s close button, then turn the handle clockwise. After closing, the handle will automatically spring back, and the operating hole will return to its original position. At this point, the circuit breaker’s energy storage indicator will display a “stored energy” status.
  • Opening (Disconnecting the Main Circuit): Press the open button. The circuit breaker will trip, and its mechanical indicator will show the “open” status.

• Opening and Closing the Grounding Switch:
  • Closing the Grounding Switch: When the chassis truck is fully in the “test” or “maintenance” position and the main circuit has been opened, insert the grounding switch operating handle into the operating hole. Turn it clockwise to its limit position, and the grounding switch will close. At this point, the chassis truck is effectively grounded.
  • Opening the Grounding Switch: After the operation is complete, turn the operating handle counter-clockwise to open the grounding switch.
• Chassis Truck Movement:
  • From “Service” to “Test” Position:
    • Circuit Breaker Open: Confirm that the circuit breaker is in the “open” position.
    • Truck Movement: Insert the operating handle into the chassis truck’s operating mechanism. Turn the handle clockwise to pull the chassis truck outward from the “service” position until it enters the “test” position. At this point, the main circuit is disconnected, but the secondary circuit plugs remain connected.
    • Status Confirmation: Observe the chassis truck’s position indicator to confirm it has entered the “test” position, and that the interlock has engaged to prevent it from being accidentally pushed back in.
  • From “Test” to “Maintenance” Position:
    • Secondary Circuit Disconnection: After confirming the withdrawable type circuit breaker is still “open,” continue turning the operating handle to pull the VCB truck out of the “test” position.
    • Plug Separation: At this point, the secondary circuit plugs will automatically separate, and the VCB truck will be completely electrically disconnected from the switchgear.
    • Full Withdrawal: Continue the operation until the VCB truck can be completely pulled out of the switchgear cubicle for maintenance or inspection.

3. Post-Operation Inspection

After the operation, a series of inspections must be performed to ensure everything is safe and ready for subsequent maintenance or power restoration.

• Chassis Truck Position Check: Verify that the chassis truck’s position indicator correctly shows the “disconnected” or “maintenance” status.
• Interlock Status Check: Confirm that the interlock mechanism is engaged, preventing the chassis truck from being accidentally pushed back.
• Tool and Handle Removal: Ensure the operating handle has been removed from the chassis truck’s mechanism and is stored properly.
• Equipment and Area Check: Inspect the interior of the MV switchgear and the operation area to ensure no tools or debris have been left behind.
• Operation Log: Record all details of the operation in the logbook, including the operator’s name, time of operation, and any unusual observations.

Safety Precautions

The safety of the operator is the top priority. Throughout the entire chassis truck operation process, the following must be strictly observed:

• No Live-Load Operation: Never operate the chassis truck when the main circuit is energized. All operations can only be performed after the main circuit is completely de-energized.
• Strictly Follow Interlocks: Never attempt to bypass or forcefully operate the interlock mechanism. The interlock system is a critical safety device.
• Personal Protective Equipment (PPE): All operators must wear and use the required personal protective equipment throughout the entire process.
• Operation by Qualified Personnel Only: All operations must be performed by certified and trained professionals.

Summary

The standardized operation of medium and high-voltage switchgear chassis trucks is an indispensable step for ensuring the safety and stable operation of power systems. Every correct insertion and withdrawal is not just a simple mechanical procedure, but a solemn commitment to personal safety and equipment reliability. The standardized process provided in this guide, through rigorous preparation, precise execution, and thorough inspection, aims to maximize the reliability and safety of every operation.

Adhering to these operating procedures can effectively mitigate electrical faults and safety accidents caused by human error, while significantly extending the service life of switchgear and its core components. A rigorous chassis truck operation procedure demonstrates a professional’s deep understanding and firm commitment to technology, safety, and responsibility. As a leading electrical switchgear manufacturer, we are dedicated to providing products that reflect these same principles, offering a standardized operational process that is fundamental to reducing unplanned downtime and maintenance costs, and a solid foundation for enterprises to achieve efficient and economical operation.