基于电子式互感器的超高压长线全电流差动保护的研究

Study of the Entire Current Differential Protection of EHV Transmission Lines Based on Electronic Transducer

通过应用自适应光学传感原理和螺线管聚磁光路结构解决了测量温漂问题和不能长期稳定运行问题,且稳态测量精度达到0.2级,非周期分量电流的最大峰值瞬时值误差小于±1%,能够精确测量非周期分量及各种交流谐波分量,且无饱和现象的光学电流互感器(OCT),利用贝瑞隆输电线路模型,构成基于电子式互感器的超高压长线全电流差动保护,这种保护原理自动地考虑了电容电流的影响,不再需要进行电容电流的补偿。仿真结果表明,分析是正确的,原理是可靠的,适合在数字化变电站中应用并推广。

Aiming at these two severe problems OCT faced, temperature excursion and unstable operation that baffle its utility in power system, the adaptive optical transducing principle and the solenoid collecting magnetic field optical path are adopted to solve the problems after analyzing the open loop mechanism of OCT. The performance of an OCT is examined by applying the standard testing system. The results indicate that under the steady state the measurement precision of the AOCT reaches class 0.2, and under the transient state the maximal peak instantaneous alternating current component error of the AOCT reaches class 1. The proposed method can measure the non-periodic component and various AC harmonic components exactly, without saturation phenomenon. Bergeron model of transmission lines is used to set up the entire current differential protection of EHV transmission lines based on the electronic transducers. This algorithm considers capacitive current automatically, and can pass over the compensation of capacitive current. Simulation results demonstrate that the analysis is correct and the algorithm is reliable. This protection method is suitable for digital substations.