Dynamic Virtual Inertia and Damping Control for Zero-Inertia Grids

Abstract: In this paper virtual synchronous generation (VSG) approach is investigated in application to low- and zero-inertia grids operated by grid-forming (GFM) inverters. The key idea here is to introduce dynamic inertia and damping constants in order to keep power gird stable during different types of faults, islanding or large power balance oscillations. In order to achieve such robustness, we introduce frequency and phase angle shift functions to VSG along with dynamics virtual generator parameters. The stability of such approach is theoretically proven and theoretical results are supported by detailed case studies in RTDS (Real-Time Digital Simulator) NovaCor 1.0 with GFM inverters dynamics simulated with 1-3 microseconds timestep using two-level universal inverter model. Case studies include all aforementioned types of faults and demonstrate increased power grid robustness and survivability in comparison with traditional synchronous generation of comparable size.