Study On Mechanism Of Abnomal Temperature Rise And Thermal Aging Of Composite Insulator

Composite insulators are the most widely used electrical equipment in power systems,which operating state are directly related to the safe and stable operation of the power grid and the stable development of the national economy.In recent years,composite insulators operated on transmission line of Foshan,Shenzhen,Dongguan,Guangzhou and other regions in China have occurred abnormal temperature rise accident,large amount of investigation show that this kind of accident are closely related to the high temperature and humidity conditions of the southern region in China.Until now,the reason why the abnormal temperature rise occurred on composite insulators still unknown.Currently,due to lack of in-depth understanding of abnormal temperature rise of composite insulaters,the grid company often replaced all the composite insulators that appear abnormal temperature rise,this blind replacement caused a great waste of the power resources.In summary,it necessary to study the mechanism of abnormal temperature rise that occur on composite insulator and the thermal aging mechanism of the umbrella and FRP rod material,so as to provide the theoretical basis for the operation and management of the grid company.Firstly,high voltage is applied to abnormal temperature rise composite insulators and FRP rod of abnormal fracture composite insulators that replaced from AC 500 kV transmission line in the laboratory.The temperature and discharge are observed in real time by infrared thermal imager and ultraviolet imager during the test,so as to study the mechanism of abnormal temperature rise occur on composite insulators.And then,according to the results of the experimental,the abnormal temperature rise of the composite insulators was divided into two forms: abnormal temperature rise at the end and abnormal temperature rise non at the end.And incorporated the experimental results of this paper and previous studies,the mechanism of two abnormal temperature rise was deduced.Furthermore,the aging test of HTV silicone rubber and FRP rod of composite insulators were carried out in the laboratory,and the samples are analyzed by SEM,FTIR,TG and TG-FTIR,in order to study the effect of abnormal temperature rise on the performance degradation of composite insulator.Finally,according to the geographical environment and climatic conditions of Guangzhou,this paper puts forward to promote the infrared temperature measurement(including the on-line infrared monitoring and artificial infrared inspection)and improve the accuracy of the determination of abnormal temperature rise,so as to reduce the blind replacement of compositor insulators by power grid,thereby reducing the waste of power resources.The results of this study can provide theoretical and engineering reference for the operation and maintenance of composite insulators in the southern region.