Performance Against Direct Lightning on 10-kV Overhead Distribution Lines with Counterpoise Wires

This article investigates the lightning performance of a 10-kV overhead distribution line equipped with grounding counterpoise wires under extremely low soil conductivity conditions. A partial element equivalent circuit model with the lossy ground being considered is adopted for lightning surge investigation. The Monte Carlo method considering natural lightning randomness is used for the flashover rate evaluation. It is found that under extremely low soil conductivity conditions, the simple vertical grounding rod is not effective in lightning protection, while the performance is significantly improved with extended counterpoise wires. The single-row counterpoise wire with a length of line span performs best. The single-row counterpoise wire with a half-length of line span is a competitive one, due to a half-cost reduction and a competitive performance. If a higher performance of lightning protection is expected, further extending the length of counterpoise wires would be ineffective. Increasing the CFO level or installing surge arresters on all poles would be the possible solution.