Abstract
Governments and investors are actively promoting the adoption of inverter-based resources (IBRs) in power systems, which accelerates progress toward a net-zero carbon footprint. Inverters used in IBRs have designed limits of fault current supply enforced by control actions, which brings challenges to protection systems. Protection elements depending on the magnitude and angle of fault current and resulting voltage drop during fault conditions are influenced by this controlled response. To address the growing challenge, this paper employs superimposed voltage quantities to implement voltage-restrained overcurrent elements. The performance of this protection element will be assessed using electromagnetic transient simulations on a modified IEEE 9-bus test system featuring a grid-connected solar photovoltaic (PV) system. Simulation results illustrate the adverse impact of infeed from the adjacent system on fault currents, and validate the effectiveness of superimposed quantity-based protection elements for power systems with IBRs.