EMT and Phasor-Domain Co-simulation of a Low Frequency AC Transmission System for Offshore Wind Integration

This work investigates the system-level interactions between a low-frequency high-voltage alternating current (LF-HVac) system using back-to back converters and the main 60 Hz LF-HVac grid. A co-simulation framework is developed by integrating high-fidelity dynamic model of the LF-HVac system in electromagnetic transient (EMT) tool PSCAD and the IEEE 39-bus system in phasor-domain (PD) program PSS/E. The developed framework is used to demonstrate the robust performances of multi-terminal and point-to-point LF-HVac systems under normal and contingency conditions. In addition, the EMT and PD co-simulation results show accurate representation of the dynamic responses with a significant one-third simulation time compared to the conventional EMT simulation approach.