Analysis of an Abnormal Secondary Voltage Accident of Capacitive Voltage Transformer

Capacitive Voltage Transformer (CVT) is an important measurement and protection equipment in power system, which has the characteristics of high electrical strength, large insulation margin and reliable operation. During the operation of CVT, its upper and lower capacitors, compensation reactors, lightning rods and other components often have faults. The faults of CVT can be found in time by judging the secondary voltage value. In this paper, an abnormal secondary voltage fault of CVT is introduced. Combined with test and disassembly analysis, it is determined that the fault is caused by breakdown of capacitor unit. Through fault simulation, this paper studies the typical CVT faults and the change law of secondary voltage, and puts forward the threshold of the secondary voltage abnormal alarm of CVT, providing important reference for CVT online monitoring.