Authors

C. Volat, M. Jabbari, M. Farzaneh and L. Duvillaret

Abstract

Preliminary results based on experimental tests in laboratory and numerical investigation concerning the live-line detection of a conductive defect in HV composite insulator are depicted. The proposed method is based on E-field sensing using a non-invasive and compact pigtailed electro-optic (EO) single-ended probe. Measurements and numerical FEM modeling were done on a clean dead-end 28 kV composite insulator on which conductive defects of different size and position were simulated. Based on these simulations, the optimal location and orientation of the EO probe were determined regarding the conductive defect length and position. Laboratory tests were performed to validate these results and demonstrate the efficiency of the new detection method. The experimental results have demonstrated that using the optimal EO probe orientation, the E-field sensor was able to detect and locate conductive defect as short as 15 mm × 1 mm in contact with the HV electrode and of 26 mm × 2 mm between sheds. Moreover, the experimental tests have demonstrated the ability of the EO sensor to detect the presence of corona discharges induced by the conductive defects.

Introduction

Composite and non-ceramic insulators (NCI) have been widely used on electrical networks since the 1980s. NCI can be found under multiple designs, materials and manufacturing processes. They are preferred to ceramic insulators because of their low weight, low installation cost, higher resistance, strength as well as higher contamination resistance due to their hydrophobic surface [1-2]. However, NCI exhibit shorter lifetime expectancy compared to their ceramic counterparts due to UV degradation, pollution, mechanical stress and low resistance to corona discharges [1-4]. The latest are generally an important problem as they can lead to sheath damage exposing the fiberglass rod, tracking the rod and thereby leading to insulator failure by reducing the total insulating length causing interfacial flashover…

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