The Study On Failure Factor In High Voltage Storage Capacitors Under Impulse Discharge Conditions

The insulation capability of High Voltage Storage Capacitors, which are the kernel elements of impulse power system, determines the service reliability of impulse power system. High voltage storage capacitors are charged under DC voltage and discharge in several microseconds. When the capacitors are in service, the insulation usually breaks down at impulse discharge stage. However, the insulation degradation mechanism of storage capacitors is lack of systematic research. Study on the failure factors of storage capacitors in work condition can guide the insulation construction design of storage capacitors, avoid latent insulation defects and effectively enlarge the life of storage capacitors. The research result can also be used to provide theoretical foundation for capacitor insulation detection and ensure the validity of insulation detection methods. Therefore, the working stability of impulse power system may be improved.This thesis aims to have a primary probe into the insulation failure mechanism of the high voltage storage capacitors at the impulse discharge stage. The main characteristics of impulse discharge stage are the fast voltage regulation and impulse current with huge peak value. The influence of impulse discharge on the capacitor insulation is analyzed on four aspects: partial discharge, space charge, thermal factor and mechanical stress. There has been a great deal of discussion about the breakdown factors of capacitor insulation on the construction aspect, according to the aging trial, dissection and electric field simulation analysis of storage capacitors. At last, the author gives some suggestions about the construction design of storage capacitors.The research result of this thesis can put forward some proposals on construction design and insulation detection of storage capacitors. The work in the thesis has practical significance on the improvement of fabrication process and the insulation property of capacitors. Meanwhile, this thesis is an attempt of researching the insulation degradation mechanism of high voltage storage capacitors, which may promote the research in this field.