Temporary measures for transformer core issues when shutdown is not possible

Temporary troubleshooting methods for transformer cores when shutdown is not possible:

① If there is an externally routed grounding wire and the fault current is relatively high, the grounding wire can be temporarily disconnected for operation. However, enhanced monitoring is required to prevent a floating potential from appearing on the core if the fault point happens to disappear.

② As transformer core manufacturers suggest, if the multi-point grounding fault is unstable, a slide-wire resistor can be connected in series with the working grounding wire to limit the current to below 1A. The selection of the slide-wire resistor is based on the voltage measured when the normal working grounding wire is opened, divided by the current on the grounding wire.

③ Use dissolved gas analysis (DGA) / chromatographic analysis to monitor the gas generation rate at the fault point.

④ If the exact fault point is located through measurement but cannot be repaired, the normal working grounding tab of the core can be moved to the same position as the fault point. This is done to significantly reduce the circulating current.