The correlation of external partial discharges and the voltage withstanding of medium voltage pin insulators

This paper studies the correlations observed in the dry leakage current shape and the voltage withstanding of medium voltage pin insulators. The development was based on laboratory tests on roughly 1,500 insulators obtained from a field research aiming at detecting prone to failure insulators, in operation, in over head medium voltage lines, in four different regions of Brazil. Field inspection methods were applied for inspection of overhead medium voltage distribution lines, and according to this research, for medium voltage levels, the best approach considers the application of ultrasonic and radio frequency detectors (antennas). Detecting equipments based on infrared and ultraviolet techniques, at least for the voltage level of 15 kV, the range of the present research, were not…