Experimental Study On The Effectiveness Of On-line Detection Of The Defects Of Zinc Oxide Arrester Equipment

The zinc oxide arrester is one of the main equipment for limiting overvoltage in a power system,it can provide certain protection level and protection margin for important electrical equipment.Its performance directly relates to the safe operation of power system.But because the zinc oxide arrester has no series gaps and works outside for a long time,it is affected by the electric stress of operation voltage,atmospheric environment and impact overvoltage.The resistance sheet and the sealing element gradually deteriorate as the operating time increases,making the leakage current of the resistance sheet flowing through the zinc oxide arrester increase.The resistive component in the leakage current can cause the temperature of the resistance sheet to rise,the active loss is increased,and even lead to the explosion of the zinc oxide arrester,which leads to a large-area blackout accident.Therefore,it is necessary for the safe and stable operation of power system to judge the online operation state of zinc oxide arrester by means of live detection.In order to effectively monitor the operation state of zinc oxide arrester,timely detection of defects of zinc oxide arrester,avoid the occurrence of major accidents,the zinc oxide 500kV porcelain housed arrester as the research object.The zinc oxide 500kV porcelain housed surge arrester for different position by the power frequency withstand voltage test under the condition of loss and damp,and the use of resistance current tester in the testing process,the infrared imaging instrument,the electrical parameters of zinc oxide arrester embedded fiber temperature sensor and fiber strength tester,temperature distribution,external temperature distribution,electric field distribution and voltage distribution characteristics were analyzed.The results show that the current-resistance current,infrared imaging and other charged detection methods used in daily production can reflect the aging and moisture-receiving defects of the lightning arrester to a certain extent;The temperature sensor is applied to monitor the temperature inside the arrester,and the method of detecting the surface temperature of the porcelain bushing of the lightning arrester by optical fiber/field intensity method is more sensitive to the defect analysis of the UHV arrester.It is possible to detect the defect status of lightning arresters in time at the early stage of defect occurrence.It provides a reliable detection method for evaluating the operation state of arresters,and finding out the degree of deterioration of arresters more efficiently and sensitively.