一种新算法在监视线保护中的应用

Application of a Novel Algorithm in the Cable Monitor Wire Protection

在煤矿电网中,传统的监视线保护一般采用二次谐波法或者利用正交变换的方法来去除直流、工频和高频干扰。为避免现有监视线保护装置的误动与拒动,提出了一种终端加电阻的改进型全波傅氏算法的交流监视线保护原理,通过采样周期的调整和算法的改进,着重解决衰减直流信号所带来的干扰。数学分析及实验证明:该方法能完全滤除直流衰减信号、直流、工频及高频杂散电流。采用该方法的监视线保护可靠准确、计算量小、降低了前端电路的硬件规模,大大提高了保护的可靠性。

In the eoalmine high-voltage power network, the second harmonics and orthogonal transformation are used to solve the interferences which are produced by DC, power frequency and high order stray currents in the tradition cable monitor wire protection. The existing problems of the protection of cable monitor wire are analyzed, that is the protection will fail to operate or unwanted operation under the disturbance circumstance. Then the protection principle of an AC monitor wire with the terminal connected to a resistor using the improved Fourier algorithm was stud- ied. By the adjustment of sampling periods and the improvement of the algorithm, it emphatically solves the disturbance by the decaying DC component. A mathematical analysis shows that the decayed DC component, DC, power frequency and high order stray currents are all completely filtered in this way. The experimental device shows that this method is reliable and accurate and has a small computation capacity. It also simplifies the front-end circuit and has a high application value. Its reliability is also greatly improved.