Voltage-time characteristics and related approximation formula for 6.6-kv solid-core-type insulator having higher lightning impulse withstand voltage

To establish an optimal lightning protection method for power distribution lines, factors such as the mechanism behind lightning surges as well as power distribution network and insulation level of power distribution lines should be taken into consideration. This study experimentally clarifies the voltage-time (V-t) characteristics of currently used 6.6-kV power distribution insulators having higher lightning impulse withstand voltage (LIWV) by considering the differences in polarity and the presence or absence of slurry. Furthermore, in this paper we propose approximation formulas based on the sparkover model for calculating the flashover characteristics of 6.6-kV power distribution insulators, which can contribute to insulation coordination throughout the power distribution system.