Criticality of Inverter Controller Order in Power System Dynamic Studies – Case Study: Maui Island

Increasing shares of inverter-based resources (IBRs) in generation mixes around the world are raising concerns about the requisite modelling complexity of IBRs. This paper presents a full order electro-magnetic transient 15th order grid-following inverter model with a novel order reduction scheme to 7th or 5th order models. These models were employed in a validated model of the Maui power system with a 97% IBR penetration. Transient simulations yield substantially different responses between the 15th order and reduced order models during periods of low system strength, highlighting the necessity for high-order IBR models in dynamic studies. Homogeneously applied parameter sweeps for stable regions of varied current controller gains were executed and dominant frequency response oscillatory modes identified. The results indicate a system stability dependence on current controller gains, system size, and complexity. Heterogeneous distributions of current controller gains were simulated, revealing a minimal difference for minor deviations.