Effectivity of Insulator Replacement to Avoiding Disturbance Caused by Lightning

The number of lightning-induced disturbances on the 70 kV Purwakarta - Subang transmission line experienced a significant increase in 2021. Regarding to the flash density in the monitoring of Vaisala application, it captured that this OHL consist of several lightning strikes around 1 km to the tower transmission. The implementation of reinforcement measures for grounding systems using multiple grounding and direct grounding methods on all towers along the Purwakarta Subang transmission line has proven to be less effective in preventing lightning-induced disturbances. Lightning-induced disturbances during the rainy season can cause flashovers of insulators on several towers simultaneously. Laboratory assessments of the insulator conditions have shown a decline in insulation and mechanical capabilities after operating for 30 years, falling below standards. Testing on electrical measurement and mechanical measurement is the require to analyze the current condition of an insulator itself. As a result of the decreased electrical capability of these insulators, they fail to withstand the disturbance current during lightning induced disturbances, leading to flashovers and even breakdowns.