Investigation of Wide Band Voltage Measurement Technology for Switching Transient Overvoltage Induced by the Operation of the Vacuum Circuit Breaker

Abstract

Accidents occurred frequently in the 35kV power system in recent years when vacuum breaker switched off shunt reactors, it’s of significant importance to measure the switching transient voltage. A wide frequency band measurement method for the switching transient voltage was proposed in this paper, in this method a capacitive voltage sensor was sealed within a composite insulation bushing filled with SF6 gas to realize high voltage insulation, and an impedance converting circuit was used to expand the band of the measurement system. The frequency response characteristic of the voltage measurement had been experimentally investigated, 3dB cutoff frequency was about 0.7Hz, the change of the voltage divider ratio in the frequency range of 50Hz-100MHz is within 5.7%, phase shift was 0.9° at the frequency of 50 Hz. This method had the advantages of wide frequency band of voltage transient measurement, comparatively low weight and suitable for outdoor condition.