Analysis Of DC Partial Discharge In High Voltage Storage Capacitor Based On Delta(t) Method

HV storage capacitor is the key device in pulse power system, and its insulating property determines the operational reliability of the pulse power equipment. However, the employed evaluation methods, including withstand test, capacitance test, leakage current measurement, etc, cannot detect defects in capacitors that do great harm to lifespan of them. Therefore, it's of great importance to find an effective assessment to seek out individuals with defects, especially to weapon system that requires no risk at all. According to insulation monitoring experience on AC high voltage equipments, partial discharge (PD) contains abundant information of dielectric and insulation. And the parameters of PDs can reveal insulation defects efficaciously. Thus, that to indicate insulation situation in capacitors according to analyses of PD under DC condition (DCPD) has practical meaning to improve reliability of impulse power system, and contributes to factory testing methods.At present, the occurrence and development of DCPD are not well understood as PD under AC. Also, a lot of questions, such as what kind of characteristic parameters can describe DCPD, what's the relationship between inner defects and characters of DCPD, how can we distinguish defects, and so on, are still waiting to explore.This dissertation aims to have a primary probe into questions mentioned above. First, a detailed explanation of DCPD occurrence and development is presented. And then an analysis method related to Delta (t) is introduced to evaluate PD data. In order to make the measurement automated, a DCPD testing system is developed. Based on the testing system, lots of experiments and analyses are done. Finally, pattern recognition and classification are applied. On one hand, it gives strong support of the validity of Delta (t), on the other hand, the results show pilot study on relationship between DCPD and capacitor defects.