Multi-dimensional evaluation and synergistic optimization for double-circuit distribution lines under transient events

Abstract

Lightning-induced Overvoltage (LIOV) represents a critical factor impacting the stability and reliability of equipment in distribution systems. Despite its significance, existing studies lack systematic analysis of LIOV characteristics and protection strategies in 10 kV double-circuit distribution lines when adjacent circuits are struck by direct lightning stroke. This study aims to quantify the effects of Surge Arrester (SA) deployment density, Shielding Wire (SW) grounding intervals, and grounding resistance on LIOV, and to propose optimal protection schemes balancing performance and cost. A hybrid simulation model, based on the Partial Element Equivalent Circuit (PEEC) method with the Variable Time Step (VTS) strategy, was developed to simulate LIOV responses in a double-circuit distribution system. Lightning current waveforms were modeled by the Heidler function, and SAs were represented by IEEE-recommended frequency-dependent circuits. Results show that SA deployment with one-pole intervals enhances the one-phase flashover lightning withstand level from 1.7 kA to 3.9 kA. This performance is better than that of SW alone where three-pole grounded SW achieve a one-phase flashover lightning withstand level of 38.7 kA. Combining one-pole SA intervals with one-pole grounded SW reduces flashover rates by 30% while maintaining economic feasibility. The findings provide valuable theoretical support for practical lightning protection designs in double-circuit distribution systems.