Detecting instrument for DC partial discharge within storage capacitor

Abstract

As for storage capacitor charged under DC and discharges with a large pulse, partial discharge detection under DC is fit for its work condition. The paper presents the principle and construction of a detecting instrument for DC partial discharge (PD) within storage capacitor as well as the results of the first stage experiments. In order to increase the sensitivity of measurement system for large capacitance, the RLC balanced detection circuit was used to detect the DC PD. After being amplified by a narrowband, gain-stable amplifier and filtered by band-pass filter, these signals were sent to the pulse polarity discrimination system, then to the computer through coaxial cable. Through the experiments, the qmax-Deltat, qmean -Deltat and n-Deltat curves related to DC PD were extracted. Then some methods such as artificial neural networks would be used to recognize the PD patterns and to determine fault types and aging degree