On-line Detection Of Partial Discharge In Switchgear Assembly

35kV and below voltage switchgear assembly is widely used in various substations, safe and reliable operation of switchgear determines the reliability of the power grid. There must be electrical, thermal, chemical, and abnormal formation which result the reduced strength of electrical insulation in the long run of electrical equipment. Many recent incidents are mostly caused by partial discharge. Therefore, research and testing of electrical equipment to prevent partial discharge characteristics of electrical equipment failure is one of the best methods.For a long time, it is a good method to diagnose the insulation condition of equipment by prophylactic partial discharge test. However, because the time interval between preventive tests is so long, it is hard to find the effects of development defects between two preventive tests, which may cause insulation accident. It is difficult and expensive to measure the run equipment, and it is unrealistic to turn off the power to do the partial discharge measurement. So it is necessary to study a reliable way to test and monitor the equipment online.In this paper, it uses the transient electric voltage based on the partial discharge characteristics to determine the PD size the and through the extended Kalman filter algorithm to locate partial discharge. It uses DSP chip as the core of hardware system. By this system, we have tested the Hohhot Power Supply 10kV substation switchgear assembly and achieved good effects.In the study we found the online testing equipment can help to keep abreast of the security status of run equipment. It can greatly reduce the use of artificial, regular inspection costs and reduce the workload of the previous outage time, reduce the stitches operation and maintenance procedures and it can also increase production, efficiency and safety benefits.