Experimental and Analytical Studies of the Effect of Non-Standard Waveshapes on the Impulse Strength of External Insulation

Various analytical methods are available for predicting the performance of insulation stressed by lightning voltages of non-standard waveshape. This paper describes experimental and analytical studies for evaluating the effectiveness of the prediction methods. Flashover characteristics of typical line insulation were determined using standard and non-standard impulse waves viz., long front, partially chopped and oscillatory impulses. The standard impulse data were used to calibrate the analytical models, which were then used to predict the performance of the insulation stressed by non-standard impulses for comparison with the experimental data.