电磁式电压互感器暂态仿真及行波传变特性分析

传统上认为电磁式电压互感器(potential transformer， PT)不能有效传变高频行波信号，因此铁路自闭贯通线在利用既有设备进行双端电压行波测距时还需进行系统的研究。文章基于PSCAD/EMTDC建立了JDZ10-10型PT等效模型，并植入自闭贯通线路中进行系统的仿真研究，利用小波模极大值法检测线路故障时电压互感器一次侧和二次侧的电压行波波头。仿真研究发现，自闭贯通线上常用的JDZ10-10型PT在0~125 kHz的低频段有较好的传变特性，能准确、无时延地传变行波波头信号和极性；但故障后1~2 ms二次侧存在一个振荡过程，因此1个一次侧波头传变到二次侧会产生多个波头。在准确识别二次侧行波第1个波头的情况下，可利用电压行波进行自闭贯通线路故障测距。该结果证明电压行波测距原理在铁路自闭贯通线路中具有适应性。

Transient Simulation of Electromagnetic Potential Transformer and Analysis on Its Traveling Wave Transfer Characteristics

Traditionally, it is considered that electromagnetic potential transformer (PT) cannot effectively transfer high frequency traveling wave signal, therefore systemic research on two terminals traveling wave based fault location for railway automatic blocking and continuous transmission lines (RABCTL) by use of existing equipments is to be conducted. By means of software PSCAD/EMTDC, an equivalent model for JDZ10-10 type of PT is built and embedded into RABCTL to carry out systemic simulation in which the wavelet modulus maxima is used to detect the voltage traveling wave front at the both sides of PT under the transmission line at fault. It is discovered in the simulation that the JDZ10-10 type of PT commonly used in RABCTL possesses good transfer characteristic in low frequency band from zero to 125 kHz and can accurately transfer the signal and polarity of traveling wave front without time-delay; during the time period of one or two millisecond after fault there is an oscillation in the secondary side of the PT, so that during the transferring process one wave front at the primary side may cause multi wave fronts at the secondary side. Under the condition of accurately recognizing the first wave front at the secondary side, the voltage traveling wave can be adopted in fault location of RABCTL. Simulation results also prove that the traveling wave based fault location principle is adaptable to RABCTL.