Measurement of surface resistance of silicone rubber sheets under polluted and dry band conditions

Abstract

Ageing and degradation of silicone rubber insulators in contaminated environments is a major concern due to their organic nature. Understanding the flashover process of silicone rubber insulators under contamination is very important and needs standardized tests and procedures. Surface resistance measurement can be used as an indication of ageing and contamination severity of outdoor silicone rubber insulators. This paper presents experimental and mathematical results on surface resistance of high-temperature vulcanized silicone rubber sheets under various environmental and contaminated conditions. Rectangular silicone rubber sheets were polluted artificially in laboratory using a modified solid layer method based on IEC 60507 and tested in a climate chamber where fog rate, humidity and temperature can be controlled. Influence of non-soluble salt deposit density (NSDD), pollution severity, relative humidity, ambient temperature, dry band location and width, and multiple dry bands on surface resistance have been investigated. The obtained results show that surface resistance decreases with increase in NSDD, pollution severity and relative humidity. Increase in surface resistance was observed with the formation of dry bands. Although surface resistance was effected by all parameters, the most dominant parameter was noted Repeatability of results was confirmed by performing each test five times and concluded that surface resistance measurement can be standardized to evaluate ageing and pollution severity of silicone rubber insulators. These results along with the available literature on equivalent salt deposit density (ESDD) measurement could be used to formulate a relation between ESDD and surface resistance that could be useful for evaluating the performance of silicone rubber insulators in wet and contaminated environments.

Novel technique for estimating pollution-associated leakage current in high-voltage insulators based on adaptive filtering in long-term recording

“…To guarantee power system continuity and quality, some research groups have focussed on determining the reliable performance limits of the electric insulators during normal operations, analyzing the different causes of leakage currents. Some attempted to analyze the optimal insulator shape and different surface treatments to minimize pollution deposits associated with leakage current (PLC), while others aimed to determine the threshold level of soluble or non-soluble polluting substances that trigger the dry band in order to prevent electric arcs [4][5][6][7][8].…”

Electrical Conductivity Modeling and Fabrication of Carbon Nanotubes/Silicone Rubber Composites for High Voltage Insulators in Regions With a Polluted Atmosphere

“…Regular washing and replacement of conventional insulators with glaze insulators is a solution to prevent their failure. [2][3][4][5][6][7] The difference between the dew point and the insulator surface temperature is the primary reason of the moisture condensation on the polluted insulator surface (Figure 1). This temperature difference can be covered by modifying the housing material by adding conductive additives (e.g., carbon nanotubes, ZnO, and carbon black) to the silicone matrix.…”

Effect of Silicone Rubber of a Waste Composite Insulator on Cement Mortar Properties

“…The composite insulators are aging gradually because of the long service time (10–15 years) and the natural deterioration due to the electric field, mechanical stress, atmospheric environment and thermal radiation [4]. The aged composite insulators cannot meet the requirements of electricity transmission, and will be discarded [5,6]. The cladding material of composite insulator is silicone rubber, and the discarding will result in resources waste and vast expanses of land occupied (Figure 2).…”