nan Arshad

Effect of dry band location on electric field distribution along a polymeric insulator under contaminated conditions

To study the effect of dry band location on electric field distribution of polymeric insulators, simulations were carried out using Comsol Multiphysics. The effect of dry band along a polymeric insulator at shed, core and junction of core and shed regions on the electric field distribution was investigated. Pollution was modelled as a 2-mm uniform conductive water layer on the insulator surface. Conductivity of pollution layer was set at 500μS/cm to simulate medium pollution conditions. Simulation was carried out by considering a 2-cm dry band at the shed, core and junction of shed and core regions respectively. The highest electric field strength was observed when the dry band was considered at the junction of shed and core region while the electric field strength was minimum along the dry band at the shed regions. The result of this study will help scientists and engineers to improve the design of weather sheds for high voltage insulators so that the possibility of dry band formation at the junction of shed and core is minimized.

Effect of pollution severity on electric field distribution along a polymeric insulator

To study the effect of pollution level on electric field distribution of polymeric insulators, simulations were carried out using Comsol Multiphysics. The effect of light, medium, heavy and very heavy pollution on the electric field and potential distribution was investigated. Pollution was modelled as a uniform conductive water layer on the insulator surface. Electric field analysis was carried out by changing the conductivity of the pollution layer. Simulation results show that electric field strength is high at the junction of the sheath and shed and minimum at the top of the shed. It was also observed from simulations that electric field stress increases with increasing pollution level. The result of this study will help scientists and engineers in the design and selection of outdoor insulators for different polluted environments.

Investigating flashover behaviour of silicone rubber insulators under contaminated conditions

Flashover behaviour of silicone rubber insulators were analysed under contaminated conditions in this paper. The modified IEC 60507 Standard was used to simulate pollution deposition on the insulator surface. Experiments were carried out at different pollution level and changing leakage distances to investigate the behaviour of silicone rubber insulators. It was shown experimentally that flashover voltage is highly dependent on pollution level and leakage distance. The result of this study can be used to investigate the ageing of silicone rubber insulators and their selection for contaminated and wet environments.

Performance comparison of silicone rubber and EPDM insulators in humid and contaminated environments

This paper investigates the effect of pollution severity and relative humidity on the performance of silicone rubber and ethylene propylene diene monomer (EPDM) insulators. Rectangular samples of silicone rubber and EPDM were used for the tests. The ramp test method was used to measure flashover voltage and leakage current at different climate conditions. Flashover voltage, arc inception voltage, as well as surface resistance of silicone rubber and EPDM coating materials were measured at various pollution severity and relative humidity levels in a fog chamber. Experimental results showed a decrease in flashover voltage, arc inception voltage and surface resistance with an increase in pollution severity and relative humidity. The result of this study can be used in the selection of polymeric insulators for contaminated and humid environments.

Influence of dry band width and location on flashover characteristics of silicone rubber insulators

This paper investigates the formation of dry bands along a rectangular silicone rubber surface and their effect on the flashover characteristics. Plate samples of silicone rubber were used for experiments and pollution was applied using the modified solid layer method based on IEC 60507. Dry bands of various widths were inserted at the ground end, high voltage end and middle part of the samples. Experiments were carried out in a climate chamber and specific values of ambient temperature and relative humidity were used. Critical flashover voltage was measured for each case and a relation between dry band width, location, and critical flashover voltage was established. The results of this study will augment our knowledge regarding the flashover of silicone rubber insulators and could be used to improve the existing mathematical models for polymeric insulators.