10kV开关柜烧线圈原因分析及改进方案设计

Cause Analysis and Improvement Design of Coil Burning in 10kV Switchgear

根据近几年湖北荆门地区常规AIS站10kV开关柜的运行数据分析,控制回路断线故障占比较大,究其原因大多是分、合闸线圈烧毁。控制回路断线会导致开关拒分或者拒合,扩大事故范围,大大降低配网供电可靠性。结合开关分、合闸控制回路图和分、合闸线圈的动作原理,做检修现场分析,发现线圈烧毁是因为正常运行时,线圈中的铁芯剩磁大,联动铁芯被吸起,缩小了联动铁芯上部顶杆与断路器分合闸拐臂之间的距离,使顶杆的加速行程不够,顶杆获取的动能不足以撞动分合闸拐臂,顶杆卡涩,致使开关拒动。因开关辅助位置节点未能及时变位而使线圈中长时间通过大电流,最终导致线圈烧毁。为解决上述问题,本文提出了在控制回路中加装温控节点的改进设计方案,通过理论分析和实践验证,加入温控辅助节点后,有效降低了线圈烧毁率。

According to the analysis of the operation data of 10kV switch cabinet in the conventional AIS station in Jingmen area of Hubei Province in recent years,the break fault of the control circuits accounts for a large proportion,most of which is caused by the burning of the opening and closing coils.The disconnection of control circuit will causes the switch to refuse to open or close,expand the accident scope,and greatly reduce the reliability of distribution network power supply.Combined with the opening and closing control circuit diagram of the switch and the operation principle of the opening and closing coils,the on-site maintenance analysis shows that the coil burnout is due to the large residual magnetism of the iron core in the coil during normal operation and the linkage iron core is sucked up,which reduces the distance between the upper ejector pin of the linkage iron core and the opening and closing crank arm of the circuit breaker,so that the acceleration stroke of the ejector pin is not enough and the kinetic energy obtained by the ejector pin is not enough to impact switching arm.The switch refused to move due to the jam of opening and closing crank arm and ejector pin.Because the switch auxiliary position node fails to change position in time,the coil passes through a large current for a long time,which eventually causes the coil to burn out.In order to solve the above problems,this paper puts forward an improved design scheme of adding temperature control node in the control loop.Through theoretical analysis and practical verification,after adding temperature control auxiliary node,the coil burnout rate is effectively reduced.