基于有限元法的避雷器阻性电流检测的相间干扰计算分析

摘要

On-line monitoring the varistor column could reflect the real performance of arresters in service. The interphase interference affects the leakage current much due to the short distance among three phase arresters. Therefore, a new method based on resistance-capacitance network model for on-line monitoring of high voltage ZnO arresters is put forward. Herein, iterative algorithm is adopted. Thus, the interphase interference of monitoring arresters can be eliminated effectively. Firstly, the leakage currents and phase angle differences are acquired by measuring the 500kV arresters and 220 kV arresters in a substation. Then, the partial capacitances through finite element method are obtained. Finally, the varistor column resistance of each section per phase is calculated. The calculated results agree well with the measured results, which demonstrates the effectiveness and correctness of the proposed method.%在线监测氧化锌避雷器阀片电阻可有效反映避雷器运行状态。避雷器实际运行时多呈一字排列且三相距离近，相间干扰对泄漏电流的影响很大。为此，提出了一种新的高压氧化锌避雷器在线监测方法，该方法基于阻容网络模型，通过对避雷器泄漏电流进行测量，采用有限元法计算避雷器部分电容，最后利用迭代算法求解避雷器阀片电阻，可有效消除相间干扰对在线监测的影响。以变电站500kV和220kV避雷器为例，计算出各相避雷器每节的阀片电阻，并与实际测量值进行对比，计算结果和测量结果吻合，验证了该方法的有效性。