Dynamic modeling of VSC-based distributed energy resources for efficient three-phase power network studies

abstract

Modern power networks, enhanced with distributed energy resources (DERs) utilizing voltage source converters (VSCs), can operate under balanced and unbalanced conditions. This situation poses key challenges for analysts conducting dynamic studies. To address this complexity, this article introduces three-phase VSC-based DER models, such as photovoltaic (PV) plants and battery energy storage systems (BESS). Dynamic phasor theory is used to reproduce the DC, 1st, and 2nd harmonics of the VSCs, tailoring specific control strategies based on symmetrical components for each DER. Positive sequence current controllers regulate DC voltage and positive-sequence AC voltage magnitude using the d-axis and q-axis currents, respectively. In contrast, negative sequence dq-axis current controllers allow modulating variables to respond independently to system imbalances. This approach distinguishes the proposed three-phase VSC-based DER models from classical average-value models. Validation on a three-phase power network yielded root-mean-square errors of below 5.67% for their fundamental internal variables. The PV plant and BESS performance was evaluated under unbalanced conditions and short-circuit faults. This confirmed significant computational advantages, with DERs running 35.73 times faster than average-value models. To demonstrate the proposed method's generalizability, the unbalanced IEEE 34-bus test system, comprising three DERs, was also evaluated under varying demand, solar irradiance and battery power. © 2025 The Author(s)