The operation reliability of capacitor voltage transformer is directly related to grid safety.The internal space of electromagnetic unit of the capacitor voltage transformer and the insulation between each element is relatively small due to design and structure of the voltage transformer

and it normally withstands grid overvoltage

the operation condition is weak and fault is easy to happen.In view of the fault of secondary voltage waveform distortion of 220 kV capacitor voltage transformer during the operation period

the reason of the fault is judged preliminarily to be the damage of shunt arrester of primary winding of the capacitor voltage transformer in accordance with its structure feature with combination of site test.The judgment is verified throughout the disassembly inspection and the test of arrester.The precautions and treatment measures for the similar fault are proposed through the fault survey of the similar capacitor voltage transformer.