Inspection of Pin Insulators in Distribution Medium Voltage Lines & Outage Reductions

This paper shows a complementary study aiming at verifying the influence of the weather conditions on the effectiveness of a previous set of techniques applied to define the operational condition of porcelain pin insulators installed in medium voltage distribution lines. The research method, as discussed in a previous paper [1], deals basically with a preliminary rough inspection with an electromagnetic noises detector and a final close inspection with an ultrasonic noises detector. During the last inspection the temperature, the wind speed and the relative humidity of the air were also recorded to populate a data base with the insulators main data. Once detected a single noisy insulator all insulators installed in the inspected pole were removed and substituted by equivalent post insulators. These insulators were further classified, tested and a comparison of field and laboratory results was used to verify the influence of the weather conditions on the noise level that defines the boundary limit of damaged & no - damaged insulators. The laboratory tests were carried out at the High-Voltage Laboratory of Federal University of Itajuba.