Protection Strategies for Integrating Battery Energy Storage Systems in Transmission Networks

Battery storage is increasingly pivotal in balancing supply and demand in modern power grids. It stores surplus energy generated by solar and wind resources during favorable weather conditions and releases it to cover deficits when conditions are less optimal. A project is underway to integrate a 150 MW/300 MWh battery storage system into a 115 kV transmission network. As a direct current (DC) source, the battery requires an inverter system to connect to the alternating current (AC) grid. Inverter control systems respond to short-circuit faults differently from traditional synchronous generators, presenting challenges to the reliability of existing protection schemes based on the well-understood short-circuit responses of conventional generators. This paper discusses the additional measures incorporated into transmission line protection to enhance reliability without compromising security and ensure compliance with mandatory regulatory standards.