胶浸纸穿墙套管电容芯体悬臂负荷下的绝缘性能研究

Insulation Performance of RIP Wall Bushing Capacitor Core Under Cantilever Load

胶浸纸穿墙套管是直流输电工程换流站直流场与阀厅的连接设备,运行条件严酷,需要长期承受机、电、热等多种应力作用,其可靠性对系统安全至关重要。胶浸纸穿墙套管是典型的长悬臂结构,机械应力集中更加突出,因此其重负荷下的绝缘性能研究具有重要意义。国内外现行标准均开展单因素试验考核,与实际多因素工况存在一定差异,尚未见有关直流穿墙套管多因素试验研究的报道。本研究以某典型胶浸纸直流穿墙套管缩比单元电容芯体为研究对象,重点开展重负荷状态下电容芯体的绝缘性能测试。试验数据表明未加悬臂负荷时局部放电合格的电容芯体,在重负荷下局部放电量、介质损耗因数及电容量未发生增长或突变;未加悬臂负荷时局部放电不合格的电容芯体,在多次局部放电测量时,局部放电起始电压和熄灭电压随着试验次数增加明显降低。研究结果为同类产品的生产、试验及运维提供参考。

The resin impregnated paper(RIP)wall bushing is the connecting equipment between the DC field and the valve hall in the converter station of the DC transmission project.It operates under harsh conditions,and needs to withstand various stresses such as mechanical,electrical,thermal effect for a long time.Its reliability is critical to the system safety.The RIP wall bushing is a typical long cantilever structure,and the mechanical stress concentration is much more prominent,so the research on its insulation performance under heavy load is of great significance.The current standards at home and abroad carry out single factor test and assessment,which is diferent from the actual multi factor working condition.There is no report on the multi factor test and research of DC wall bushing.In this paper,the capacitor core of a typical RIP DC wall bushing scaling unit is taken as the research object,focusing on the insulation performance test of the capacitor core under heavy load.The test data show that the partial discharge quantity,dielectric dissipation factor(tan 8)and capacitance of the qualified capacitor core without cantilever load have not increased or changed under heavy load;For the capacitor core with unqualified partial discharge quantity when no cantilever load is applied,the partial discharge initial voltage and extinction voltage decrease significantly with the increase of test times when partial discharge measurements are made for many times.The research results provide reference for the production,test,operation and maintenance of similar products.