基于高频保护通道信号的三相自适应重合闸方法

提出了一种用于区分输电线路瞬时性故障和永久性故障的新方法：利用高频通道及其信号区分瞬时性故障和永久性故障，从而实现三相自适应重合闸。通过使用高频通道等传播常数模式理论，对高频电流信号在三相电力线载波通道上的传输特性进行了分析后得知：高频电流在多导线系统中传播时，虽然高频设备只加工于一相，但实际上高频信号是沿着多相导线的相间传播的。对于高频信号在多导线系统中的传播特性，可采用等传播常数模分量法分解为与导线数相等的n组模分量进行分析，且可利用网络关联矩阵的原理对各种故障情况下接收的高频信号进行较为准确的计算。由此提出了利用超高压线路高频保护通道的信号传输特性来判别故障类型的新方案，该方案为解决三相自动重合闸重合于永久性故障的问题开辟了新的思路。仿真与计算结果表明：各种故障情况下接收高频电流信号的特征与基于模传输理论的高频通道计算结果十分吻合；短路故障点位置对高频接收信号几乎没有任何影响。理论分析和大量的EMTP仿真结果显示了该方案的有效性和正确性。

THE STUDY ON THREE-PHASE ADAPTIVE RECLOSURE BASED ON CARRIER CHANNEL AND SIGNAL TRANSMISSION

This paper brings forward a whole new scheme of three-phase adaptive reclosure, which uses the carrier channel and its signals to distinguish transient faults and permanent faults. By applying the equal-transmission-constant mode theory the propagation characteristic of high-frequency current, transmitted on the power line carrier channel, has been examined in detail. It is concluded that when the high-frequency current transmitted on the multi-line systems, although the high-frequency signal transmitting equipment is only applied on one phase, actually the high-frequency signals are transmitted along the channels between one phase and another. Adopting the equal-transmission-constant mode theory, the transmission characteristics of high-frequency signals on multi-line system can be simply analyzed by decomposing into n mode components to be equal to the number of lines. Furthermore, the received carrier signals in various fault cases can be accurately computed by network-associated matrix. Accordingly, based on the propagation characteristics of the carrier current, a novel three-phase adaptive reclosure is proposed, which solves the problem of three-phase reclosor closing on the permanent faults. Simulation and computation results show that in various fault cases the characteristics of received high-frequency current signals is approximately equal to the computation result of carrier channel based on the mode transmission theory, and the location of a fault point has less influence on the received high-frequency current signals. Theoretical analysis and EMTP simulation tests show that the proposed scheme is correct and valid.