金属氧化物限压器压力释放过程热力参数分析  

Thermodynamic Parameters in Pressure Release Process of MOV

作　　者：刘羿辰 彭珑 方泳皓 周玮 董勤晓 王晨星 马鑫晟 刘慧林 LIU Yichen;PENG Long;FANG Yonghao;ZHOU Wei;DONG Qinxiao;WANG Chenxing;MA Xincheng;LIU Huilin(State Grid JiBei Electric Power Research Institute,Beijing 100045,China;China Electrical Power Research Institute,Beijing 100192,China)

机构地区：[1]国网冀北电力有限公司电力科学研究院,北京100045 [2]中国电力科学研究院有限公司,北京100192

出　　处：《电瓷避雷器》2023年第5期59-66,共8页Insulators and Surge Arresters

基　　金：冀北本部管理科技项目(编号:52018K190026)。

摘　　要：金属氧化物限压器(MOV)是串联补偿装置电容器组重要的过电压保护设备。当限压器组中某一台MOV单元出现贯穿性击穿故障时,一旦超出MOV的压力释放能力,易造成MOV爆炸。为了验证MOV在实际电流工况下的可靠性,笔者根据国内串补采用的无垫块(A结构)和有垫块(B结构)两种MOV结构,建立了瞬态热气流场等效计算模型。针对型式试验、实际故障和极端故障的3种电流工况下,MOV单元出现贯穿性击穿故障时,其内部的气体发热和扩散情况进行了仿真研究。研究表明:MOV压力释放过程中,MOV内部压强增大的同时,伴随着空气温度的急剧升高,是MOV瓷套损坏的主要原因;电弧初期30 ms内的电弧能量注入水平对MOV瓷套内部压强的影响极大。在这段时间内,故障电流注入瓷套内的能量要远远大于型式试验工况;与型式试验工况相比,实际故障电流下MOV压力释放过程中的内部压强和温度的峰值显著提高,峰值时刻大幅提前,对MOV压力释放不利;MOV加装垫块后,瓷壁和顶盖最大压强显著降低,有利于压力释放性能的改善。Metal Oxide Varistor(MOV)is the important overvoltage protection equipment for series capacitor.When a MOV unit in the MOV group has a through breakdown fault,it may exceed the pressure release capacity of the MOV and cause the explosion of the MOV.In order to check the reliability of the MOV under actual current conditions,according to the structure of a MOV in China,an equivalent calculation model of transient thermal gas flow field was established,and the internal gas heating and diffusion of the MOV were simulated under the condition of type test,actual fault and extreme fault.The results show that during the pressure release process of MOV,the increase of internal pressure of MOV and the sharp increase of air temperature are the main reasons for the damage of MOV porcelain bushing;The arc energy injection level within 30 ms at the initial stage of arc has a great influence on the internal pressure of MOV porcelain bushing.During this period,the energy injected into the porcelain bushing by the fault current is much greater than that under the type test condition;Compared with the type test condition,the peak value of internal pressure and temperature during MOV pressure release is significantly increased under the actual fault current,and the peak time occurs significantly earlier,which is unfavorable to MOV pressure release;When the cushion block is installed on MOV,the maximum pressure of porcelain wall and top cover is significantly reduced,which is conducive to the improvement of pressure release performance.

关 键 词：金属氧化物限压器 压力释放 热力参数 瞬态流热场 

分 类 号：TM53[电气工程—电器] TM761.12