Comparative Analysis of Grid Following and Grid Forming Inverter Models for Studying Low Inertia Power System and Its Performance Test in Weak Grid using PMView

This thesis explores the importance of inertia in the power grid traditionally provided by the rotating machines and as the penetration of the Inverter Based Resources (IBRs) increases in the grid, it brings new obstacles regarding grid reliability and stability. An advanced form of inverter (Grid-Forming type) has been compared with the conventional inverter type (Grid-Following) in an Electromagnetic Transient Software (PSCAD) under three scenarios where the system’s inertia is reduced to 50%, 25%, and 12.5%, with faults applied at three different locations: PV Point of Interconnection (POI), one bus away from PV POI, and the synchronous generator bus. Furthermore, the GFL and GFM inverters are compared in a test system set-up using PMView, an IBR model review platform developed by ERCOT, in low Short Circuit Ratio (SCR) systems in which the SCR value is gradually decreased from a value of 10 up to an SCR value of 1.5. The results indicate that the GFM inverter model offers a faster fault recovery response with better system performance in low inertia power system. It is also observed that while the GFL inverter model is stable up to an SCR value to 2.5, the GFM model performs well even at a low SCR value of 1.5.