Puncture Phenomena and Mechanism Analysis of a RTV Coated Cap and Pin Insulators in a Steep-front Impulse Voltage Test
作者机构：Electrical Engineering DepartmentTsinghua UniversityBeijing 100084Chinaand also with Department of High VoltageChina Electric Power Research Institute Co.LtdBeijing 100192China DepartmentTsinghua UniversityBeijing 100084China Department of High VoltageChina Electric Power Research Institute Co.LtdBeijing 100192China
出 版 物：《CSEE Journal of Power and Energy Systems》 (中国电机工程学会电力与能源系统学报（英文）)
年 卷 期：2021年第7卷第4期
页 面：832-839页
核心收录：
学科分类：0808[工学-电气工程] 0809[工学-电子科学与技术（可授工学、理学学位）] 08[工学] 0807[工学-动力工程及工程热物理] 0805[工学-材料科学与工程（可授工学、理学学位）] 0702[理学-物理学]
基 金：supported by the National Natural Science Foundation of China(51577099).
主 题：Cap and pin insulator puncture RTV coating steep-front impulse voltage test
摘 要：In recent years,more than 6 million room temperature vulcanized(RTV)silicone rubber coated cap and pin insulators with high mechanical ratings were used in ultra-high voltage transmission lines in China to improve pollution performance.However,the unexpected puncture phenomena of RTV coated insulators were exposed during steep-front impulse voltage tests;for instance,the steep-front impulse voltage test pass rate decreased to less than 50% for 550 kN glass insulators with RTV coatings.The steep-front impulse voltage test is the most effective method used to check the insulation quality of cap and pin insulators・This unexpected phenomenon once caused serious concerns to power utilities.In this paper,several possible factors that affect the puncture of insulators were analyzed.Then,the extent of the decline in the breakdown of the 550 kN glass cap and pin insulators with and without RTV coatings were studied.The initial puncture location was then found,and the developmental process of the arc on the insulator surface in steep-front impulse voltage tests was observed with an ultra-high-speed intensified charge coupled device camera.Lastly,a breakdown mechanism is proposed.The puncture phenomena of a RTV coated insulator in a steep-front impulse voltage test is essentially an electrical breakdown of the internal insulation・The RTV coating induces the close adherence of the arc to the surface of the insulator.Such closeness changes the arc development path on the insulator surface and facilitates easy breakdown in the shed weak part.All these factors result in a significant increase in the breakdown probability of RTV coated insulators in steepfront impulse voltage tests.
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