Comparison of AC Icing Flashover Performance of 110 kV Composite Insulators

The electrical insulation strength of existing composite insulators would reduce with the shed configuration which is easier to be bridged by the ice in icing regions.Icing flashover of insulator strings can lead to power outages,even worse,threatens the safe operation of power networks at normal service voltage.Based on the icing characteristics of four types of 110 kV composite insulators in the multi-function artificial climate chamber,the icing influence,icing flashover influence and flashover process were investigated and compared.The results show that the characteristic exponents a(characterizing the influence of pollution degree ESDD on the flashover voltage Uf) of the 110kV anti-icing composite insulators are smaller than that of the normal composite insulator in the same icing conditions.Moreover,the percentage of voltage increases between the former and latter increases with the increase of the pollution degree ESDD.Namely,the pollution is more serious,the flashover voltage of anti-icing composite insulators is higher than normal.So the reasonable composite insulator’s umbrella structure can improve the icing flashover performance.The results can offer some consult for the selection and design of composite insulator used transmission lines in the icing regions.