Improvement of measurement techniques in PD pulse detection in large HV equipment

摘要

Partial discharge (PD) measurement has been used as a tool to assess insulation integrity for many years. In terms of detection of PD pulses, a proper assessment of insulation integrity relies on accurate acquisition of the PD pulse signal.However, measurement errors may arise due to the measurement facilities involved. The PD pulse is usually measured by variously a combination of the following facilities: a PD detector, a pulse generator/known capacitance simulating the PD pulse forcalibration, a recording instrument, e.g. an oscilloscope/spectrum analyser/ computer-based data acquisition system. The PD pulse is transmitted from the detection point to the facilities and between the facilities through connecting cables. Twoconnecting cables are usually used, one carrying the pulse signal and the other as the earth return. Unfortunately, in studies of PD pulse propagation, too little attention has been paid to the effects of the measurement system on obtained results, andthis may account for the inconsistencies in results obtained from different groups.This paper discusses one aspect of the measurement system, the role of connecting cables. Much of this may seem self-evident, but this is not reflected in the experimental approaches found variously in the literature of PD pulse measurement.