Modeling and Modern Control of Wind Power

Chapter 9Model Predictive Voltage Control of Wind Power Plants

Haoran Zhao and Qiuwei Wu

Technical University of Denmark

In this chapter, an autonomous wind farm voltage controller based on model predictive control (MPC) is proposed. The commonly used devices for reactive power compensation and voltage regulation of the wind farm are coordinated to keep the voltages of all the buses within the available range. These devices include static Var compensators (SVCs), static Var generators (SVGs), wind turbine generators (WTGs) and on-load tap changing (OLTC) transformers. By optimization of the reactive power distribution throughout the wind farm, the dynamic reactive power reserve can be maximized. Two control modes are designed: for voltage-violated and normal operating conditions. A wind farm with 20 wind turbines was used as the test case to verify the proposed control scheme.

9.1 Introduction

Nowadays, the increasing penetration of wind power and growing size of the wind farms have introduced technical challenges to the maintenance of voltage stability [1]. Due to the long distances between large wind farms and load centers, the short-circuit ratios (SCR) are small and the grid at the connection points is weak [2], which can cause large voltage fluctuations. Moreover, grid disturbances may cause cascading trips of wind turbine generators (WTGs). Therefore, the technical requirements of modern wind farms for voltage support, as specified by system operators, have become more ...