高速列车过分相VCB延时断开故障测试及原因探究

High-speed Train Over-phase VCB Delayed Disconnection Fault Testing and Cause Investigation

高速列车车载真空断路器(VCB)性能是列车安全稳定运行的重要保证之一。近年来,国外某型号动车在过分相时出现VCB延时断开故障,导致只能通过降弓方式来预防带电过分相引发的安全隐患。针对以上问题,推测其原因是VCB触头间电弧烧蚀或牵引变压器合闸时刻励磁涌流导致的VCB过载造成。主要针对牵引变压器合闸励磁涌流进行研究,通过现场测试和PSCAD仿真探究励磁涌流的影响因素和实际可达到的最大值。结果表明,列车过分相VCB完成合闸后实测最大电流达到756.67 A,不会对VCB触头造成实质性损伤。牵引变压器励磁涌流大小主要受VCB合闸电压相角和变压器铁芯剩磁影响,且励磁涌流并非导致VCB触头熔焊的主要因素,VCB合断时触头间的电弧烧蚀才是造成VCB触头熔焊的主要原因。

Train on-board vacuum circuit breaker(VCB)performance is one of the important guarantees of safe and stable operation of the high-speed train.Recently,a foreign EMU ran into a VCB delayed disconnection fault when passing a neutral section,resulting in lowering the bow to prevent the safety hazard caused by charged passing.In view of the above problem,it is presumed that the cause is the VCB contact between the arc ablation or traction transformer closing moment excitation inrush current caused by VCB overload.This paper focuses on the traction transformer closing excitation inrush current research,through field testing and PSCAD simulation to explore the influence of the excitation inrush current factors and the actual maximum achievable.The results show that the measured maximum current reaches 756.67 A after the train over-phase VCB closes,which will cause substantial damage to the VCB contact.The size of the traction transformer excitation inrush is mainly affected by the phase angle of the VCB closing voltage and the remanence of the transformer core.And the excitation inrush current is not the main factor leading to the VCB contact fusion welding,VCB closed between the contacts of the arc ablation is the main cause of VCB contact fusion welding.