Development of a Wind Turbine Generator Volt-Var Curve Control for Voltage Regulation in Grid Connected Systems

Growing interest in renewable energy sources has led to an increased installation rate of distributed energy resources (DERs) such as solar photovoltaics (PVs) and wind turbine generators (WTGs). The variable nature of DERs has created several challenges for utilities and system operators related to maintaining voltage and frequency. New grid standards are requiring DERs to provide voltage regulation across distribution networks. Volt-Var Curve (VVC) control is an autonomous grid-support function that provides voltage regulation based on the relationship between voltage and reactive power. This paper evaluates the performance of a WTG operating with VVC control. The evaluation of the model involves a MATLAB/Simulink simulation of a distribution system. For this simulation the model considers three WTGs and a variable load that creates a voltage event.

I. Introduction

With increasing interest in renewable energy sources, more distributed energy resources (DERs) are being connected into the grid [1]. This creates challenges associated with distribution circuit’s voltage regulation [2]. Maintaining the voltage within the operational limit is considered to be a critical issue for utilities. It is critical to support system voltage by maintaining it within the required limits of the grid to prevent any adverse effects to the system. Traditionally, voltage swings were mitigated by implementing load tap changing transformers, capacitor banks, and other voltage regulation devices. With new advances in power electronics, DERs such as photovoltaic (PV) inverters and wind turbine generators (WTG) can also provide reactive power within their rated capacity limits to help mitigate voltage deviations [3], [4].