Performance Comparison Between GFM and GFL Inverters In 100% Inverter-Based Power Systems

Low frequency nadir and high rate-of-change-of - frequency (ROCOF) are the challenging issues to realize the concept of “100% inverter-based power system” or “non-inertia system” when all inverter-interfaced generating systems are considered as non-inertial systems. The appearance of new control technique named “grid-forming” (GFM) makes this concept becomes more of reality. However, there are various questions about the suitable GFM methods which should be used or how system operates with different control methods from inverter-based systems, etc. In this paper, the operation of droop based GFM inverter is verified, in comparison with other control methods including virtual synchronous generator (VSG) typed GFM and grid following (GFL) inverters. Simulation results are obtained by a modified IEEE 9-bus model built in PSCAD software.