Publication
An Advanced Voltage Regulation Control for Distributed Wind Turbine Generators
Abstract
Power grids that incorporate a variety of distributed energy generation must be capable of maintaining system voltage in the allowable range against potential disturbances caused by load variations and variable generation provided by renewable energy sources. Advances in grid support functions enable wind turbine generators (WTGs) to provide reactive power in order to regulate voltage. Herein, this paper investigates the ability of a WTG to provide voltage regulation in a distribution system. An advanced control is designed and tested by subjecting the system to a load step, which causes a low voltage event at the end of the distribution system. A stability analysis is performed in order to guarantee that the WTGs reactive power control is able to provide voltage support and improve the response of the distribution system. MATLAB/Simulink is used to carry out the advance control analysis method and to perform simulation.
AI Summary
This paper develops a model-based voltage-regulation controller that enables distributed Type-IV wind turbine generators to provide reactive-power support without the instability that can occur with high-gain proportional control. Using a MATLAB/Simulink model of Sandia’s SWiFT distribution system, the authors inject an exponential chirp into the WTGs to identify the system’s reactive-power-to-voltage dynamics and use the resulting transfer function to design a compensator with substantially greater stability margin. The advanced controller is then applied to three WTGs under changing wind output and a load-induced low-voltage event; it regulates the turbine PCCs to their voltage targets while maintaining the load-bus voltage around 0.97 pu, compared with a baseline below 0.95 pu. The results show that system identification can be used to design stable, higher-gain WTG voltage control that provides stronger and more precise voltage support than conventional Volt-Var control.
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