Control Interaction Modeling and Analysis of Grid-Forming Battery Energy Storage System for Offshore Wind Power Plant
Fangzhou Zhao, Xiongfei Wang, Zichao Zhou, Lennart Harnefors, J. Svensson, Łukasz Kocewiak, Mikkel Peter Sidoroff Gryning
Abstract
With the increasing deployment of offshore wind power plants (WPPs), the grid-forming (GFM) battery energy storage system (BESS) has recently emerged as an attractive solution to improve the dynamic performances of WPPs. However, the control interactions of the GFM-BESS and offshore WPP, under different grid strengths, tend to complicate the controller-parameter tuning. This paper presents a modeling method for analyzing control interactions of offshore WPP and GFM-BESS, which sheds clear insights into the critical controller parameters to the system dynamics. Differing from conventional methods, a frequency-domain model of GFM-BESS, obtained by taking the Laplace transform of the corresponding state-space model, is developed first. This allows the impedance model of offshore WPP, including a black-box model of long transmission cable, to be flexibly integrated. Based on the model, both closed-loop transfer-function and pole-based dynamic analyses are then performed. Electromagnetic transient simulations corroborate the effectiveness of the model and analysis.