The influence of atmospheric conditions on the leakage current of ceramic insulators on the Colombian Caribbean coast

Abstract

The contamination of electrical insulators is one of the major contributors to the risk of operation outages in electrical substations, especially in coastal zones with high salinity levels and atmospheric pollution. By using the measurement of leakage-currents, which is one of the main indicators of contamination in insulators, this work seeks to the determine the correlation with climatic variables, such as ambient temperature, relative humidity, solar irradiance, atmospheric pressure and wind speed and direction. The results obtained provide an input to the behaviour of the leakage current under atmospheric conditions that are particular to the Caribbean coast of Colombia. Spearman's rank correlation coefficients and principal component analysis are utilised to determine the significant relationships among the different variables under consideration. The necessary information for the study was obtained via historical databases of both atmospheric variables and the leakage current measured in over a period of 1 year in a 220-kV potential transformer insulator. We identified the influencing factors of temperature, humidity, radiation, wind speed and direction on the magnitude of the leakage current as the most relevant.

Modeling leakage current of ceramic insulators subject to high pollution levels for improving maintenance activities

“…The coefficient of correlation supports the statement, giving a value of −0.98. Several authors worldwide have investigated the high correlation between the magnitude of the leakage current and the weather [17,[25][26][27][28][29][30]. Once more, this relationship is confirmed.…”

“…To obtain the model, the leakage current and weather variables were taken into account, considering their existing correlations [17]. The created model is based on simple regressions with the purpose of determining the optimal washing times for the electrical insulators of outdoor substations.…”

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

“…The Spearman correlation coefficient, which measures the strength and direction of monotonic nonlinear relationships between two ranked variables, was computed for the environmental variables to assess their underlying non-linear relationship with leakage current. As there may be a relationship between the different variables that could mask a relationship with leakage current [31,32], to determine these variables' intrinsic relationship with leakage current we also computed the partial Spearman correlation coefficient between raw leakage current and the environmental variables, which obtained a moderate average correlation above 0.20 when controlling the effect of the other variables. For example, when we analyze the partial correlation of leakage current with wind speed, it may indicate the relationship between these variables by removing possible humidity-wind speed, wind direction-wind speed and temperature-wind speed interactions.…”

Laboratory investigation of the impact of air pollution on partial discharge inception voltage of insulators in a specific region

“…According to reliable statistics, a high percentage of service interruptions are caused by moisturized outdoor insulators' contamination. Nowadays, air pollution is a problem in industrial countries and developing areas of the world [4], [5]. Air pollution constituents, in rain or fog conditions, cause the formation of a conductive layer which leads to flow of leakage current and discharges on transmission line insulators surfaces [6], [7].…”