Research on the method to restrain the corona happened in switch cubicle

Switch cubicle has been widely used in switchgear substation and switchgear house. However, the switch cubic accidents are greater due to various causes. Further more, the single accident would damage other switch cubicles, because of its special assembling. Some accidents caused by insulation problem happened in our power supply company. And the corona happened inner the switch cubicle was found, when its working. The corona happened mainly in the gap between the organic insulation material and iron plate, and near the flange of bushing. The reason, which would lead to discharge, was analyzed in this paper. The research results show that electrical field concentrate on the gap between the organic insulation material and iron plate. Therefore discharge would happen at this place firstly. An experimental system was set up to analyze this discharge. In the experimental system, the ultraviolet-imaging instrument was used to locate the discharge position, and the partial discharge instrument was used to show the magnitude of discharge. Based on the research, a new way was pointed out to avoid corona, that a kind of semiconducting material was used to fill the gap. And the validity of this way was testified by the experiment and practice. Some proposal also was presented to the equipments manufactory. Some improvements should be adopted in the design, such as using shielding ring and conducting flange.