Optimizing Transmission Line Arresters Deployment for Ground Wire Lightning Protection in Mahakam Interconnection Network: A Case Study on 150 kV Sangatta-Maloy Line

This study investigates the effectiveness of Transmission Line Arresters (TLAs) in mitigating the impact of lightning strikes on ground conductor within the Mahakam Interconnection System, specifically along the 150 kV Sangatta-Maloy transmission line. Effectiveness was evaluated through simulation and modeling of 29 sample towers out of a total of 214 towers, with lightning strike currents varied at 50 kA and 100 kA. Two TLA placement methods were assessed: sequential installation on the first five towers, and alternating installation across five towers. Both configurations successfully reduced lightning current to 1.20 kA at Tower T.39 and 1.30 kA at Tower T.247. TLA application also suppressed overvoltages from 500 kV to approximately 145 kV, well below the Basic Insulation Level (BIL) of 650 kV. However, based on residual voltage profiles, Method-2 (Alternating Placement) demonstrated superior and more consistent protection, especially at towers located farther from substations, thus enhancing system reliability. A total investment of approximately IDR 1.62 billion is required to procure and install 30 TLAs, representing a cost-effective strategy for reinforcing lightning protection on the Mahakam interconnection line, considering the potential asset damage if left unmitigated.