| Non-ceramic insulators, particularly those made of silicone rubber (SIR), are increasingly being used in both distribution and transmission systems.; Leakage current (LC), leading to dry-band arcing, is considered one of the most important causes of aging in SIR insulators.; In this investigation, salt-fog tests are conducted to test the influence of SIR insulator profiles on their aging performance. Three forms of aging are identified during the study: no visible damage, erosion, and failure. A very good correlation is discovered between these three forms of aging and the LC low frequency components.; Shed spacing, shed diameter, alternate shed design and shed profile are the SIR profile parameters investigated in this study.; Two different methods to compute the current density along the contaminated and wet SIR insulator's surface are investigated. The first method, based on the field theory approach, uses the commercial software FEMLABRTM to compute the current density. The conductivity of the contamination layer used in the calculations is extracted from the measured equivalent salt deposit density (ESDD) for each of the different regions of the insulator surface. The second method is based on the circuit theory approach, and the insulator surface is divided into different sections for resistance calculations to account for different contamination levels.; In summary, the LC low frequency components are employed to study the relationship between SIR insulator profiles and aging, and it is demonstrated that LC low frequency components can be correlated with aging in SIR insulators. In fact, the results indicate that the SIR insulator profile has an enormous influence on the aging performance of SIR insulators. (Abstract shortened by UMI.)... |
