有机复合介质储能电容器直流局部放电检测系统的研究

Study on HVDC Partial Discharge Detecting System of Organic Dielectric Storage Capacitors

储能电容器的工作过程是在高压直流条件下进行较长时间充电，然后在很短的时间放电，从而在负载上形成高电压、大电流的脉冲。为了检测该电容器的性能，开发了一套在高压直流条件下进行储能电容器局部放电检测的装置，并给出了初步试验结果。为提高大电容测量系统的灵敏度，该装置采用并联RLC型电桥平衡回路来提取放电信号，该信号经窄带、增益稳定的放大单元后，再经过带通滤波器、数据采集，最后得到所需试验数据。试验表明，该系统可以获得不同缺陷电容器发生局部放电时放电幅值的时间分布谱图，这为直流局部放电的统计分析和模式识别、判断故障类型和介质老化程度打下了良好的基础。

As the storage capacitor charged under DC and discharges in a short time, which form a high voltage and large current pulse. A set of HVDC detecting instrument used for storage capacitor was developed to detect the characteristic of the capacitor and the results of the first stage experi- ments were presented. In order to increase the sensitivity of measurement system for large capacitance, the RLC balanced detection circuit was used to pick-up the DC PD. After amplified and fil tered, these PD signals were obtained. Through the experiments, the magnitude of PD over time in different capacitors were got, which would be used to recognize the PD patterns and to determine fault types and aging degree.