What to do if the secondary side of a current transformer is open-circuited?

1. Immediate Reporting and Protection Deactivation: Upon discovering an open circuit, immediately report to dispatch and deactivate any potentially malfunctioning protection devices.

If the ammeter displays abnormal readings or the protection device issues a disconnection signal, prioritize deactivating the relevant protection devices.

2. Load Reduction and Safety Preparation: Request a reduction in the primary load current. If the transformer is severely damaged (e.g., smoking, abnormal noise), the load must be transferred or the power supply deactivated.

Operators must wear insulated boots and gloves, use qualified insulated tools, and ensure at least two people work together.

3. Short-Circuiting the Fault Point: Short-circuit the secondary side with a jumper wire at the nearest test terminal. If sparks are generated during short-circuiting, the fault point is below the short-circuit point; if no sparks are generated, the fault point may be in the upstream circuit.

If the open circuit is at the transformer body terminal and cannot be short-circuited, request a power outage.

4. Troubleshooting and Repair: Inspect easily loosened parts (such as terminals, poor contacts). External problems can be addressed immediately; if the fault is internal (such as a damaged relay), report it to a professional.

If abnormal noise persists after short-circuiting, it indicates an internal open circuit, requiring power outage and repair.

5. Fire Handling: If a fire is caused by an open circuit, first disconnect the power supply, then use a dry powder fire extinguisher. Never use water to extinguish the fire.

Precautions: Open circuits on the secondary side are strictly prohibited, as this will create a high-voltage hazard.

During the handling process, continuously monitor the meters to prevent the fault from escalating.