Effect of pollution severity and dry band location on the flashover characteristics of silicone rubber surfaces

Abstract

This paper investigates the flashover and ageing behavior of silicone rubber insulators under various contamination and dry band conditions. Effect of pollution severity, leakage distance and dry band location on the flashover characteristics of silicone rubber insulator was investigated. Flashover voltage and electric field distribution were measured under different pollution severity levels and dry band conditions. Effect of leakage distance on flashover voltage was also studied. Tests were carried out in a climate chamber and specific values of humidity and ambient temperature were used. A commercially available simulation package, COMSOL Multiphysics, was used to validate the experimental results. Electric field and potential along a silicone rubber sample were studied under different pollution severity and dry band conditions. Fourier transform infrared spectroscopy was used to analyze the chemical changes on the insulator surface and investigate the hydrophobicity recovery property of silicone rubber after flashover tests. The results of this study will further our knowledge regarding the flashover of silicone rubber outdoor insulators under contaminated and dry band conditions and could be used to improve the existing flashover models.

Evaluation of Long-Term Boiling Water Immersion as Artificial Aging Test of Silicone Rubber Insulators

“…The recovery rate is affected by the composition of methyl groups and the presence of low molecular weight molecules that tend to expand on the surface. The main reason for the recovery of silicon rubber insulation in salt-fog test is a displacement of low molecular weight and in boiling water immersion test is reorientation of methylgroups [11].…”

Pollution Flashover Voltage of Transmission Line Insulators: Systematic Review of Experimental Works

“…The flashover voltage under the influence of dry band was discussed in references [36], [62], [70], [71], [74], [112], [132]. The flashover voltage of glass insulators under dry bands with five scenarios of pollution distribution were tested in [36].…”

“…As suggested by [74], the effectiveness of insulation of polluted insulators increased with increased dry band length. Meanwhile, the effect of the dry band position on the performance of plate insulators was investigated by the authors in [112] (Figure 17). From the results, the flashover voltage with the dry band placed in the middle of the insulator was the highest; the flashover voltage with the dry band placed near electrodes of the insulator was lower than that with the dry band placed in the middle of the insulator.…”

A mathematical model for investigation of dry band location on 22 kV bushing with and without RTV coating: Experimental study

“…Hence, in order to determine the level of pollution and the variables affecting the performance of the pollution, the flashover performance of polluted bushings must be studied [8] . Pollutants that have built up on the surface of the bushing throughout the course of its use do not conduct when the surface is dry.It turns into a conductive layer when it's moist, which may be what starts the leakage current [ 9 , 10 ]. When the voltage stress across the dry band is greater than the withstand capacity, an arc may form.…”