Grounding requirements for transformer core.

Set a separate yoke clamp grounding transformer grounding wire. If the core encounters the upper clamp and causes a grounding fault, the grounding current only flows inside the core clamp, and no current passes through the core grounding transformer grounding wire, which will cause the worker to mistakenly think that the core has no fault; after setting, no matter where the core encounters the clamp, a control loop will be formed through two grounding external wires, so that the grounding current can be accurately detected from the outside.

The core grounding plate is placed in the middle of the yoke cross-section. In this way, no matter where the yoke strap insulation bolt is located and where the fault grounding point is located, the max.  induced voltage of the control loop is only 1/4 of the turn voltage and the max. grounding current at this time is only about a few volts, which is much smaller than when the core grounding plate is placed elsewhere.

If the core grounding plate must be placed in other places due to problems such as inconvenient on-site installation, the insulation bolts of the yoke strap and the grounding plate should also be placed at the top corners, to avoid the generation of large currents.