ABSTRACT:
Grid-forming (GFM) control of Type-3 and Type-4 wind turbine generators (WTGs) has attracted substantial attention in power systems research; however, the limited overcurrent capability of power electronics converters continues to deteriorate the grid strength of the evolving power systems. Synchronous wind, also known as a Type-5 WTG, offers a unique GFM solution to address grid integration and grid strength issues by keeping the grid largely synchronous at very high integration levels of renewable generation. A Type-5 WTG interfaces with the electric grid via a synchronous generator driven by a variable-speed hydraulic torque converter; hence, the wind rotor operates in variable-speed mode for maximum power generation, and the generator shaft remains synchronous to the grid. This presentation gives the modeling and demonstration effort of a high-fidelity model of a Type-5 WTG in a power-hardware-in-the-loop (PHIL) testing environment using NREL ARIES. The PHIL demonstration shows that a Type-5 WTG inherently behaves as a GFM unit and can obtain similar performance in terms of power responses, wind rotor dynamics, and efficiency compared to a Type-3 WTG in high-wind conditions. Various oscillation damping mechanisms have be demonstrated with the synchronous machine based wind turbine. The testing result provides further insight into how Type-5 WTGs can benefit the smooth transition to power systems with high reliability and resiliency.
Presented by Weihang Yan, NREL