Protection methods for electronic current transformer during extreme circumstance

The performance of electronic current transformer could been deteriorated, even destroyed during some extreme circumstance, for example, overvoltage or over current. This paper introduces the protective problems of several parts for ECT, LPCT (low power current transformer), Rogowski coil, power supply system and signal processing circuits in high-voltage side, the corresponding protective methods and design criterions have been proposed. Errors on LPCT induced by leakage current are analyzed. The analysis results show that errors induced by protection components could be ignored through selecting appropriate parameters. Type test results show the ECT based on the proposed methods meets IEC 0.2 class requirements, and the validity of the measures have been proved.