Lightning protection of MEA's 24 kV distribution lines using overhead ground wires

This paper employed Alternative Transient Program- Electromagnetic Transient Program (ATP-EMTP) as the main tool for system modeling and simulation to determine the impact of lightning current occurring in distribution system. The results show that when the average lightning strikes to distribution line the voltage across insulator is higher than 1500 kV which exceeds the critical-impulse-flashover of insulator (CFO) of 205 kV resulting in the power outage. We also found that if the grounding distance of distribution line increase from 40 meters to 200 meters, the back-flashover rate increase from 0.96 to 14.36 flashes/100 km/year. However, the critical lightning current of the distribution line system reduce from 107 kA to 8 kA on condition ground resistance is not more than 1 ohm. All the results in this paper could be served as a guideline for grounding system design and modification of grounding standard in distribution lines in the future.