White Paper on Resonance Stability Assessment Using the Impedance-Based Stability Criterion

To ensure a future-proof electrical energy supply, the expansion of renewable energy sources and grid infrastructure is essential. This challenging task largely falls to distribution grid operators, who must also ensure that inverter-connected systems in Germany are tested for resonance stability in the future. This white paper provides a practical introduction to the topic, guided by the impedance-based stability criterion and findings from grid and inverter impedance measurements. Results from measurement campaigns to determine grid and inverter impedances are interpreted within the context of the stability criterion, identifying how resonance stability should be ensured in the future grid.