Operational Safety Procedures and Maintenance Requirements for Low-Voltage Pole-Mounted Circuit Breakers

Safe operation and regular maintenance of low-voltage pole-mounted circuit breakers are essential for long-term system reliability.

1. Operational Safety Procedures

Operations must be strictly regulated under dispatch control, following the "Three Tickets and Two Systems" (work permit, operation ticket, emergency repair order; read-back and supervision systems). Operation tickets must use dual equipment identifiers (e.g., "XX kV XX Line XXX Circuit Breaker") and list detailed steps and safety measures. Steps must be verified via simulation diagrams before execution, and operations must be performed by two personnel—one operator and one supervisor.

Post-operation, status indicator lights must be checked to confirm correct execution. Mechanical locks (e.g., on the energy storage lever) and warning signs (e.g., "Line Under Maintenance") should be used to prevent misoperation. Operation tickets are valid for up to 5 days; reissuance is required for changes in work content, location, or personnel. Dedicated safety supervisors are mandatory for high-risk operations such as critical temporary installations, special tasks, seasonal work, multi-trade cross operations, heavy lifting, special high-altitude work, and live-line operations.

For smart breakers with integrated communication modules, remote operation must ensure security and reliability. Remote control should use encrypted protocols (e.g., MQTT/CoAP over TLS), with identity verification (password/biometrics) and full operation logging. The remote control center must have robust communication and data processing capabilities to monitor real-time parameters (current, voltage, temperature). Upon fault detection, the system should promptly diagnose, trigger alarms, and initiate protective actions. Mobile video cameras can be used to verify status indicator changes, ensuring accuracy in remote operations.

2. Operations in Adverse Weather

Special precautions are required during typhoons, heavy rain, or other extreme conditions. Before operation, check seal integrity, moisture protection on contacts, and ensure no water or debris on lines. Use insulated tools and proper PPE (protective clothing, gloves, safety shoes, helmet, goggles). In cold regions, verify heater functionality to prevent SF6 liquefaction or degraded vacuum interrupter performance. In hot climates, ensure cooling systems function to prevent overheating. In dusty environments, inspect and clean dust buildup. In corrosive areas, check insulation and metal parts for damage and apply anti-corrosion treatments as needed.

3. Fault Diagnosis and Handling

A systematic approach is required for fault management:

• Failure to operate: Check control circuit integrity, energy storage status, and mechanical interlocks.

• Unintended tripping: Verify setting values, protection characteristics, and environmental influences.

• Contact erosion: Inspect contact wear, arc extinguishing performance, and load compatibility.

• Gas leakage (SF6 breakers): Examine seals, pressure readings, and environmental effects.

• Loss of vacuum (vacuum breakers): Test power-frequency withstand voltage, arc color, and contact travel.

Fault handling must follow the principle of "diagnose first, then act," ensuring accurate fault location, effective resolution, and controlled safety risks.