Enhanced Grid Stability via Grid-Forming Inverters Fed by Hybrid Renewable and Storage Systems

The transition towards renewable energy generation is resulting in the replacement of traditional synchronous machines (SMs) with power electronics, leading to a consequent reduction in overall grid inertia. Grid-forming inverters (GFMs) have emerged as a critical technology to address the challenges associated with low-inertia systems, providing essential voltage and frequency regulation. This study simulates the integration of grid-forming inverters in the electrical grid using Matlab/Simulink. The inverter's DC-side source consists of a photovoltaic plant integrated with a hybrid energy storage system (HESS), which combines battery and supercapacitor technologies to ensure voltage support and fast response. The paper examines the contrasting behaviors of a grid composed solely of synchronous machines versus one incorporating grid-forming inverters, with a particular focus on the response to sudden changes in grid load. Additionally, the stability of the HESS to maintain the voltage on the inverter DC bus in case of PV generation loss, and the resulting inverter response are evaluated.The findings demonstrate the enhanced frequency and voltage stability achieved through the integration of inverters. The key performance metrics, including frequency nadir, Rate of Change of Frequency and transient extinction time all exhibit significant improvements, underscoring the superior dynamic response of inverter-based resources when implemented with appropriate control strategies.