Fault Diagnosis and Troubleshooting of 10kV High-Voltage Switchgear

I. Common Fault Types and Diagnostic Methods

Electrical Faults

• Circuit Breaker Failure to Operate or Maloperation: Check the energy storage mechanism, closing/tripping coils, auxiliary switches, and secondary circuits.

• High-Voltage Fuse Blown: Measure voltage across the fuse terminals; inspect busbar joints, cable terminations, and protection relay settings.

• Busbar Discharge or Insulator Damage: Listen for discharge sounds, check temperature at busbar connections, and visually inspect insulators for flashover traces.

Mechanical Faults

• Disconnector Stuck or Jammed: Inspect lubrication of mechanical linkages, operating spring condition, and auxiliary switches.

• Operating Mechanism Spring Failure: Check for spring fatigue or aging; test the energy storage mechanism.

Insulation Faults

• Insulator Damage or Busbar Discharge: Visually inspect insulator surfaces for flashover marks; use an infrared thermal imager to monitor temperature at busbar joints.

Control Circuit Faults

• Relay Protection Maloperation: Verify protection relay settings, inspect CT secondary circuits, and check stability of control power supply.

II. Fault Handling Methods

Electrical Fault Handling

• Circuit Breaker Failure to Operate or Maloperation: Manually store energy and test closing operation; replace damaged coils; repair or replace faulty auxiliary switches.

• High-Voltage Fuse Blown: Tighten busbar joints, adjust protection settings, and replace the fuse.

• Busbar Discharge or Insulator Damage: Tighten busbar connection bolts, clean dust from insulator surfaces, and install dehumidification devices.

Mechanical Fault Handling

• Disconnector Stuck or Jammed: Lubricate linkage mechanisms, replace springs, and manually reset auxiliary switches.

• Operating Mechanism Spring Failure: Replace the spring, apply lubricant, and manually test the energy storage function.

Insulation Fault Handling

• Insulator Damage or Busbar Discharge: Replace damaged insulators; perform power-frequency withstand voltage tests on the busbar.

Control Circuit Fault Handling

• Relay Protection Maloperation: Recalibrate protection settings, repair CT secondary circuits, and stabilize the control power supply.

III. Preventive Maintenance Measures

• Perform regular infrared thermography to detect overheating issues.

• Conduct partial discharge (PD) testing to identify early signs of insulation aging.

• Maintain mechanical components by lubricating moving parts to prevent jamming.

• Inspect cable terminations regularly to prevent loosening or oxidation, reducing arc discharge risks.

• Clean dust and moisture periodically to improve insulation performance.

Note: These methods should be applied flexibly according to actual site conditions. Always ensure safety during troubleshooting. When necessary, contact qualified professionals for assistance.