Transient stability assessment of grid following converter for offshore wind applications

Abstract

In recent years, the application of transient stability analysis methods on conventional power systems has been extended to grid-connected converters. The dynamics of converters within a certain frequency region can be modeled using two-order differential equations with similar configuration to the swing equations. This presentation will first discuss the performance of various transient stability assessment methods such as time-domain simulations, phase portrait analysis, equal-area criteria, and Lyapunov's direct method. These methods are used to estimate the region of attraction (ROA) of a post-disturbance converter with grid-following control. However, the dynamics of the dynamic equations of converters are control parameter-dependent with time dependency due to the control actions during the post-fault disturbance period. Insights are provided into the equations and analysis is extended to include certain nonlinear and time dependency characteristics of the converter control in the ROA estimation, which is verified by time-domain simulation. At the end, the potential and challenges of nonlinear stability assessment for offshore wind power plants is discussed.

Speaker Bio

Guangya Yang is currently Senior Scientist at the Technical University of Denmark. He received his PhD from the University of Queensland, Australia in 2008, after which he joined the Technical University of Denmark. From 2020 to 2021, he worked full-time as specialist on electrical design, control, and protection of large offshore wind farms at Ørsted. His current research interests focus on the stability and protection of converter-based power systems, with an emphasis on offshore wind applications. He and his team have conducted pioneering investigations on the application of synchronous condensers for low-inertia systems. He is the convener of IEC61400-21-5 on Configuration, functional specification, and validation of hardware-in-the-loop test bench for wind power plants. In addition, Yang is the coordinator of the H2020 Marie Curie Innovative Training Network project InnoCyPES (Innovative Tools for Cyber Physical Energy Systems) and the lead editor of the Power and Energy Society section in IEEE Access.