1. Overload protection current transformer
2. Differential protection current transformer
3. Grounding protection current transformer.
The current transformer for protection is mainly coordinated with the relay device. In the event of a short circuit or overload and other faults on the line, it provides a signal to the relay device to cut off the fault circuit to protect the safety of the power supply system. The working conditions of the current transformer for protection are completely different from the current transformer for measurement. The current transformer for protection only starts to work effectively when the current is several tens of times larger than the normal current.
Main requirements for protection transformers
1. Reliable insulation
2. A sufficiently large accurate limit coefficient
3. Sufficient thermal stability and dynamic stability.