Realizing a Virtual Synchronous Generator Inverter with Overcurrent and Fault Handling Capability as Synchronous Generator

Abstract

High penetration of inverter-based resources (IBRs) in the grid increases the need for them to provide similar grid support functions as traditional synchronous generators (SGs). The virtual synchronous generator (VSG) is an effective approach to controlling IBRs to behave like SGs. However, previous VSG IBRs, with their limited inverter overcurrent capability, cannot mimic the SGs during faults and other high current transient conditions. As a result, these IBRs cannot provide the same level of voltage support, black start, protection, and transient stability as traditional SGs. This paper realizes the VSG inverter with overcurrent and fault handling capability so that it provides grid support as the SG even during grid transients. The 6 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">th</sup> -order SG model is adopted considering the sub-transient performance, and the inverter control is discussed. The implementation is fully tested with both simulation and experiment in different fault types (balanced and unbalanced) and fault impedances. The results show that with the 6 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">th</sup> -order model and control, the VSG inverter can perform the same as the SG even during grid faults. This verifies that VSG IBRs can provide grid support as the SG even during grid faults.