4500A晶闸管换流阀局部放电问题的分析与处理

首次采用6英寸晶闸管的KGWF-4500/167全新晶闸管,其换流阀绝缘型式非常重要。针对型式试验中局部放电值超标问题,笔者通过采用紫外成像仪探测发生放电的区域,对放电区域进行研究分析,假设放电位置并验证假设的方法,最终判定:局部放电发生在下方水管与铝支架之间,它们之间的空气间隙距离小是导致局部放电超标的根本原因。随后又分析换流阀内绝缘,找一个最小空气间隙安全距离估值,并在现场采取措施验证估值。最小空气间隙距离得到验证后,再设计30%的安全余量,重新设计绝缘支撑板,从根本上解决局部放电超标问题,用于实际工程西北-华中联网背靠背灵宝扩建工程之中。文中介绍了一种发现问题、分析问题、解决问题的快速有效方法,适用于处理实际工程换流阀型式试验过程中出现的问题。

Analysis and Treatment of Partial Discharge Excess in 4 500 A Thyristor Valve

The problem that the partial discharge level has exceeded acceptable level during dielectric type test of the KGWF-4500/167 thyristor valve that consists of 6 inch thyristor firstly was the dielectric problem,which could affect the safe and reliable operation of thyristor valve.By investigating with a UV camera detailed inspecting in this area,supposing the position appearing partial discharge and verifying it,writer conclude finally partial discharge activity appeared between the bracket and the lower water pipe.The reason partial discharge exceeded acceptable level was that the air clearance was not enough.After a minimum air clearance value has been assessed and verified,the laminate supporting plate has been redesigned by considering 30% margin of air clearance.So,the problem of partial discharge exceeded acceptable level has been resolved.The supporting plates have been redesigned and applied in actual xibei-huazhong BtB extending project.In this paper,a rapid method of finding,analyzing and solving problem witch comes forth during type test of actual project has been introduced.