Comparative Performance of 11kV Silicone Rubber Polymeric Insulators with HVAC and HVDC Excitations using the Rotating Wheel Dip Test

Summary

This paper presents an experimental study of silicone rubber polymeric insulators for 11kV systems using a Rotating Wheel Dip Test (RWDT) based on IEC 62730:2012. The main purpose of this study is to compare the aging performance of polymeric insulators under AC and positive DC excitations. The procedures of the Standards were adopted to perform AC and positive DC tests on different insulator designs. A conventional polymeric insulator design has been selected and compared with insulators having textured surfaces. Textured surfaces have been developed by Cardiff University to increase the creepage distance and enhance tracking/erosion performance. The results of long term testing are obtained, and both voltage and leakage current signals were measured and digitized through a computerized data acquisition system. The signals were then processed to calculate other significant parameters of the test results. In particular, the magnitude and shape of leakage current and the cumulative dissipated energy on the insulator surface were observed to characterize each insulator. Using these parameters permits direct comparison between different insulator designs under alternating and positive direct voltages. Continuous monitoring of the shed surface and insulator trunk using an IR camera were undertaken to assess the temperature distribution along the insulator profile, and hydrophobicity tests were performed before and after termination of the test to check the degradation level of the insulator surface and its material. Localized surface conductance measurements were evaluated using a conductance meter with probes fabricated according to IEC 60507. This evaluation helps to distinguish and understand the variation trends of conductance and its distribution on each insulator surface.

Additional informations

Authors

Carneiro Moreira Rodrigo Otávio, Pretorius, Pieter, Liu Yuan