AC pollution flashover circuit model for composite insulator based on multiple arcs series

With the increasing application of composite insulator in the power system, pollution flashover often occurs. However, no model can exactly predict pollution flashover voltage of composite insulator at present. Based on high-speed photography of AC pollution flashover process, a model, which is in view of pollution severity, air pressure, shed configuration, and hydrophobicity level and which is suitable for composite insulator with any shed configuration, is proposed. Influences of pollution severity and hydrophobicity on flashover voltage and pressure characteristic exponent are analyzed, from which derives a calculative formula of flashover voltage. Calculated results from the model, validated by experiments, demonstrate that there is a power function relationship between flashover voltage and hydrophobicity level β, and characteristic exponent of hydrophobicity level β is the same as that of pollution severity. Meanwhile, the exponent characterizing the influence of air pressure increases with the fall of pollution severity and the rise of hydrophobicity. Copyright © 2010 John Wiley & Sons, Ltd.