Enabling 100% Renewable Power Systems Through Power Electronic Grid-Forming Converter and Control: System Integration for Security, Stability, and Application to Europe

Abstract

In accordance with European plans, dynamic controls are developed to allow for system-wide integration of 100 % renewable energy sources (RESs) interfaced through power electronic converters while maintaining security. At the heart of the development is the concept of the grid-forming resource (GFR) which brings together both the technologies of renewable energy resource and grid-forming converter. Extending on an extensive review, a grid-forming converter control and protection scheme is presented to ensure operation under small-and large-signal transients as needed for overall system security. The scheme is shown to be practical in offering inertial response emulation and frequency control based on droop characteristics to maintain power balances rapidly, to control voltages, as well as to support transient stability enhancement under grid faults. The integration with the control of wind energy conversion systems (WECSs) creates a grid-forming wind park as the prototype of the GFR. Feedforward signals exchanged between grid and resource-side controls enhance fast overall controllability. The principal claims are substantiated based on a scenario developed in the European project initiative MIGRATE with a focus on the Irish power transmission system. The model comprises more than 2000 individual WECSs grouped into wind parks, where ten wind parks are GFRs. The transient behavior of this scenario comprising 100 % converter-interfaced generation is shown to be superior compared with a counterpart case comprising synchronous machinery. The results validate the fact that GFRs with their proposed controls are expected to be key elements in creating a renewable and secure electric power system.