Role of air gaps on AC withstand voltage of an ice-covered insulator string

The influence of the number and position of air gaps on the 50% AC withstand voltage, V₅₀, of a short string of 5 IEEE standard insulator units covered with ice was experimentally investigated and numerically simulated. The results show that the V₅₀ is affected by the number and position of the air gaps. The results also show that the presence of a partial arc along the air gap close to the high voltage (HV) electrode leads to a redistribution of the voltage along the ice-covered insulator. Based on the obtained results, suggestions for improving the performance of line insulators under icing conditions were proposed