A method of deterioration measurement of gap-type arresters for distribution systems

ZnO surge arresters with a series gap have been generally applied to 6kV power distribution systems. However, the deterioration diagnostic method of the arresters still has not been sufficiently established in hot-lines. Therefore, we have attempted to establish a method to diagnose the deterioration by measuring the leakage current of arresters. Then, we measured the changes in the respective leakage currents of the arresters and of the series gap with a spacer and the ZnO element of them against the number of operation times when the arresters were operated repeatedly by a large impulse current of 10kA, 4/10 μs. In this work, to clarify the cause of the change in the leakage current of the arresters, the inner surface of the spacer is observed by using an X-ray photoelectron spectroscope after the arrester was operated repeatedly by the large current. Then, a method of deterioration measurement of gap-type arresters for distribution systems is proposed