The Experimental Study Of Partial Discharge Detection Technology In GIS Equipments

In the recent years, China’s power industry develops rapidly, the voltage level and the system capacity increase constantly. Depending on the advantage of its compact conformation, small footprint, good insulation, GIS has been widely used. The power system fault has occurred and has increased year by year. The insulation is the weak link of the electrical equipments. Therefore, The research of the insulation performance is a hot research on home and abroad.In this paper, a real220kVGIS test model is used as the research platform, four insulation defect models which are the actual insulation defect in the GIS are set in the air chamber, insulation defects in each model, respectively, It uses the pulse current detection method, ultrasonic detection method, the ultra-high frequency detection method and the analysis method to components of SF6gas to detect the partial discharge, By the combination of electrical means and chemical means, it strives to achieve a breakthrough in the detection means.The article has studied on the analysis of SF6. It has done lots of simulation experiments. There are four insulation defect model. On each insulation defect model, it uses50kV small power system to pressure. Firstly, PD occurs by the step-up way with ladder-type. Then it uses the constant voltage method to do the test study. It does sample test each three hours and it continues pressuring for more than20hours. Through the study it can be draw:As the time of pressure increased, the content of decomposition products from SF6increase. For the existence of insulating material, the CF4content in SF6gas decomposition products soars and gradually increases as the pressure.In this paper, the sensitivity of the pulse current technology and the ultrasonic detection technology was studied. Four insulation defect models are set in the air chamber. The pulse current method and the ultrasonic method were used to detect the PD simultaneously. The results showed that the sensitivity of the ultrasonic detection method was higher when the atmospheric pressure of the bus segment0.3～0.4MPa under the laboratory condition.The ultrasonic method and the UHF method are the main means of insulation detection in GIS. This paper has also been a large number of experimental studies to these two detection techniques. Four insulation defects were set on the GIS. It used a large power system of750kV, a voltage value between the inception voltage and the breakdown voltage is selected to do the constant pressure test. At the same time, it uses the pulsed current method, the ultrasonic method and the UHF method to do the insulation defect test. It recorded the spectrums of each discharge and found the difference from the different spectrum. Followed by location...