基于小波变换的新型暂态行波方向保护

以往的行波方向保护只对电压或电流中的一种行波波头进行信号处理,因此失去了另一电气量的信息,有时会引起方向保护的误判.为此作者提出了一种新型线路保护方案,利用小波变换提取线路故障时保护测量点的暂态电压、电流的特征量,并对二者的波形进行比较,根据其相似程度对线路的区内、区外故障作出准确、快速的判断.采用ATP(Alternative Transients Program)对各种类型故障所做的仿真计算验证了所提出的保护原理的正确性和有效性.

A NOVEL TRANSIENT TRAVELLING WAVE BASED DIRECTIONAL PROTECTION USING WAVELET TRANSFORM

In former travelling wave based directional protection the signal processing is conducted only for the wavefront of current or voltage travelling wave, so the information of another electrical quantity is lost, sometimes it can cause misjudgment of directional protection. The authors propose a new transmission line protection scheme in which the eigen-quantities of transient voltage and current at the measuring position are extracted while the fault of transmission line occurs. The waveform of both transient voltage and current are compared and according to the similar extent the accurate and fast judgment for whether the fault is inside or outside the protection zone can be performed. By means of Alternative Transients Program (ATP) a large amount of simulation for various kinds of faults the correctness and effectiveness of the proposed protective principle are verified.