Volt-Var Curve Control Using Wind Turbine Generators and Photovoltaic Inverters for Voltage Regulation

With increasing interest in renewable energy sources, more distributed energy resources (DERs) such as solar photovoltaics (PVs) and wind turbine generators (WTGs) are being connected into the grid. PVs and WTGs may cause voltage deviations due to their dependency on variable and intermittent natural resources, e.g. solar irradiance, and wind speed. This creates a challenge for utilities and system operators in terms of maintaining voltage stability. New grid standards are requiring PV inverters to provide reactive power using Volt-Var Curve (VVC) control to ensure voltage regulation in distribution systems. VVC control is an autonomous grid support function for voltage regulation based on the relationship between voltage and reactive power. This paper demonstrates the ability of a WTG and a PV inverter to jointly provide voltage regulation in a distribution system using VVC control. A simulation model of a distribution system is used to evaluate the performance of the VVC control. For this simulation, the model considers three WTGs, a PV inverter, and a variable load that creates voltage variability.