基于数字信号处理器和小波包重构算法的配电网接地选线装置的研究

根据配电网单相接地故障中零序电流的特点,利用小波包对零序电流进行分解,在按能量最大原则选取的特征频档带中通过比较重构后电流瞬时值的符号进行接地故障选线,仿真结果表明该方法既能实现相电压峰值附近的故障选线,也能实现相电压过零点附近的故障选线;并针对该方法构建了基于数字信号处理器(DSP)的配电网接地选线硬件平台,试验结果表明,该软硬件平台运算速度快、抗干扰能力强、运行稳定.

RESEARCH ON FAULTY LINE DETECTION DEVICE FOR DISTRIBUTION NETWORKS BASED ON DIGITAL SIGNAL PROCESSOR AND WAVELET PACKAGE RECONSTRUCTION ALGORITHM

According to the feature of zero sequence currents in distribution network where the single-phase- to-ground fault occurs, a comprehensive intelligent method to detect the faulty line is proposed. In this faulty line detection method, first the zero-sequence current is decomposed by wavelet package, and then the signs of the reconstructed instantaneous current values are comprehensively compared in the characteristic band that is chosen based on the principle of maximum energy. A lot of simulation results by alternative transient program show that the proposed method can realize the faulty line detection when the phase voltage is close to its peak value as well as the phase voltage is close to its crossover point. On this basis a hardware platform for grounding line detection of distribution network based on digital signal processor (DSP) is constructed and on this platform the proposed comprehensive intelligent faulty line detection method is verified. Test results show that the presented software and hardware possess following advantages, such as high calculation speed, high anti-interference ability, high performance to cost ratio and stable operation.