交流电压下绝缘子表面电荷对闪络电压影响的主导因素  

Dominant Factors Affecting Flashover by the Presence of Surface Charge Under AC Voltage

作　　者：李大雨 张贵新[1] 王天宇 LI Dayu;ZHANG Guixin;WANG Tianyu(Department of Electrical Engineering,Tsinghua University,Beijing 100084,China)

机构地区：[1]清华大学电机工程与应用电子技术系,北京100084

出　　处：《高电压技术》2021年第12期4199-4206,共8页High Voltage Engineering

基　　金：国家重点研发计划(2017YFB0902500);国家电网公司总部科技项目(环保型管道输电关键技术)。

摘　　要：表面电荷积聚是造成绝缘子沿面绝缘强度下降的一个重要原因,影响着电力系统的安全可靠运行。为此采用试验和仿真相结合的方法,通过在绝缘子表面预置电荷的方式,区分电荷消散初期和消散一段时间以后2种情况进行闪络试验,研究交流电压作用下电荷存在对闪络电压影响中起主导作用的因素。结果表明,该主导因素随电荷消散过程发生变化:在电荷消散初期,绝缘子表面浅陷阱中电荷脱陷对闪络电压影响起主导作用,它可以使闪络电压下降约34%;电荷消散一段时间后,深陷阱中电荷引起的电场畸变成了影响闪络电压的主导因素,然而这种影响具有较大的随机性,最大可以使闪络电压大约下降30%。研究还表明,交流电压下,无论何种分布特点的电荷都会造成闪络电压的降低,这是与直流电压下的不同之处。Surface charge accumulated on polymer insulating materials is considered as one of the main factors leading to insulator flashover, which affects the stable operation of power systems. By pre-depositing charge with different distribution characteristics on the insulator surface, we analyzed the dominant factors of surface charge’s influence on flashover under AC voltage through experiments and simulations. The experiments are performed under two different conditions: in the early stage of charges decay and after some time of the decay. The results suggest that the dominant factor changes with the process of charges decay. In the early stage of charges decay, the charges de-trapped from shallow traps is the main factor leading to the flashover, which enables the flashover voltage to drop by about 34%. After the charge decays for some time, the distortion of electric field caused by charges in deep traps plays a dominant role. However, this effect is uncertain, which may result in a maximum drop in flashover voltage of about 30%. It has also been shown that charges on the insulator surface always leads to the decrease of AC flashover voltage regardless of the polarity and the distribution characteristic of the charge, which is different from DC voltage.

关 键 词：主导因素 表面电荷 闪络 种子电荷 电场畸变 

分 类 号：TM216[一般工业技术—材料科学与工程]