Design of Multifunctional Electromagnetic Transient Model for Grid-Forming Inverters

This paper introduces a versatile electromagnetic transient dynamic model for grid-forming inverter-based resources using the PSCAD software platform. The model offers a range of features, including the ability to choose from different types and combinations of DC sources, such as ideal DC source modules, photovoltaic (PV) modules, battery modules, and combined PV and battery modules. It also allows for the selection of either switching or averaged inverter models. The model encompasses various controller algorithms, including Pf/QV-based droop control, virtual synchronous machine-based control, and conventional outer-voltage-inner-current control in different domains, such as the dq domain, the ..alpha....beta.. domain, and sequence-domain control in the dq domain. Additionally, it provides options for different current-limiting schemes, such as saturation-based and latching-based current limiters, along with anti-windup protection. Moreover, the model is adaptable to different MVA ratings and complies with the IEEE Std. 2800 requirement of negative-sequence current leading negative-sequence voltage 90 degrees-100 degrees for interfacing transmission systems. The model's flexibility in power circuits, its multifunctional capabilities in operation and control, and its detailed modeling of controls and dynamics make it suitable for the study of various power system aspects requiring detailed modeling, such as investigating transient stability for interconnection studies, and impacts on protection systems for fault studies.