摘要
目前宁夏电网750 kV变压器高压套管均为油纸电容型套管,采用弹簧压紧密封结构。套管导电杆除导通电流外还承受压紧弹簧的拉力,从而将油枕、电容芯、气中瓷套、法兰以及油中瓷套等元件与导电杆紧密连接在一起,形成稳定的套管结构。导电杆一旦发生断裂,将导致变压器一次回路断线及套管失稳,进而引发变压器跳闸、套管及变压器出线装置损坏,甚至短路、起火等严重故障。通过保护动作波形分析、现场试验检测及解体检查,对一起750 kV变压器高压套管导电杆断裂故障进行了分析,结果表明套管导电杆断裂原因为用于连接上节铜导电杆与下节铝导电管的纯铜连接件强度不足,在压紧弹簧拉应力作用下,经长期运行发生累积变形断裂。
At present, all of the HV bushing of 750 kV transformer in Ningxia power grid are oil impregnated paper capacitance graded type bushing, which adopt spring pressure sealing structure. In addition to make the current through, the conductive tube also sustains the tension of the hold-down spring, so that the top housing,the condenser core, the air side porcelain insulator, and the oil side porcelain insulator are closely connected with the conductive rod, forming a stable mechanical structure. Once the conductive tube fails, it will cause transformer winding disconnection and bushing instability, which will lead to transformer trip, bushing and outlet device damage, even transformer winding short circuit and fire accident. Based on the relay protection operation fault waveform analysis, field test, disassemble and inspect, a conductive tube fault of 750 kV oil impregnated paper capacitance graded transformer bushing is investigated. The result shows that the design strength of the copper connector used to connect the upper copper tube and lower aluminum tube is insufficient, after a long period of operation, the connector eventually fails under the cumulative effect of the tension of the hold-down spring.
作者
马奎
周秀
MA Kui;ZHOU Xiu(State Grid Ningxia Electric Power Co.,Ltd.,Yinchuan Ningxia 750001,China;State Grid Ningxia Electric Power Research Institute Yinchuan Ningxia 750011,China)
出处
《宁夏电力》
2022年第2期31-35,65,共6页
Ningxia Electric Power
基金
宁夏自然科学基金项目(2021AACO3503)。
关键词
变压器套管
导电杆
故障
transformer bushing
conductive tube
fault
