Current Transformer Troubleshooting

There should be no open circuit on the secondary side of the current transformer in operation. Once the open circuit occurs on the secondary side, high temperature caused by excessive iron loss may burn out the current transformer or enhance the voltage of secondary winding, thus breaking down the insulation and leading to the danger of high voltage electric shock. Therefore, when replacing a meter such as an ammeter, active power meter and reactive power meter, please ensure the current circuit in short circuit before operation. After replacement, connect the meter in the secondary circuit and then remove the short-circuit wires while checking if the meter is normal. In case sparks appear when removing the short-circuit wires, that means the current transformer disconnects, please short the loop again and confirm the meter loop isn’t an open circuit. When removing the short-circuit wires of the current transformer, please stand on an insulated pad and consider a protector to stop the current transformer loop. When it finishes work, the protector can be put in use.

If the current transformer makes a buzz sound, please check if the internal core is loose, fasten the core bolt.

Shell of the current transformer’s secondary side shall be grounded reliably.

When the insulation resistance of the current transformer’s secondary side coil is lower than 10~20M ohms, drying process is required to recover the insulation before use it again.

When the current transformer gets faults, safety operation of the primary system circuits will be affected, please report promptly to the higher authorities and heads of departments concerned to cut off the fault current transformer timely, then treatment it. As for the open circuit of secondary winding, treatments shall be implemented according to actual conditions. After necessary safety precautions are made according to relevant regulations, the current transformer can be put in use again.