철도 피뢰기진단의 불확성 고려

초록

This paper presents a method for diagnosis of railway arrester considering uncertainty. Arresters, being the best protective devices against transient voltages, deteriorate due to absorption of moisture during use, repetitive operation during over-voltages and manufacturing defects. Various diagnostic techniques are suggested for monitoring deterioration of arresters. The technique based on the amplitude of leakage current measures the RMS or peak values of leakage current components. After the measurement of total leakage current, harmonics of leakage current components are analyzed using a microprocessor based device. From experimental results, the level of leakage current is analyzed for soundness of the arrester condition. Harmonics of leakage current components occur due to nonlinear characteristics of railway arrester. Since leakage current contains uncertain characteristics of power system voltage, the probability density functions of leakage current components can be obtained for ZnO arrester. This paper presents a probabilistic approximation method for the harmonic currents analysis in diagnosis for railway arresters. Mean and variance of harmonic currents in railway system are obtained based on leakage current components. The statistical characteristics can be helpful to reduce the diagnostic error for railway arrester."