Equalizing capacitors of circuit breaker play an important role in improving voltage distribution between breaks

and preventive test of the capacitors is a reliable way to understand their operation conditions. In this study

the factors influencing the measured capacitance were analyzed via capacitor test with different connection modes for a 500 k V porcelain pillar circuit breaker. The data of manufacture’s test

hand-over test and preventive test of the 500 k V porcelain pillar circuit breaker were compared to obtain the factors influencing the capacitance measurement of the equalizing capacitor and their influencing degrees in different test conditions. In the capacitance measurement of the capacitor test with reverse connection mode

the capacitance increment between breaks is about110 p F

while the value is about 40 p F in the test with positive connection mode. Therefore

the capacitor test with positive connection mode should be taken to facilitate the capacitance monitoring.