Voltage Regulation in Distribution Systems using Distributed Energy Resources

There has been a growth in the development of Distributed Energy Resources (DERs) in recent years. However, further penetration of DERs is being limited by voltage rise problems caused by reverse power flows. The IEEE 1547 standard, the national standard for interconnection of DERs to the distribution grid, was amended in 2014 to allow DERs to provide voltage/ frequency regulation, which has led to the development of smart inverters with inverter reactive and frequency control modes. Due to the original IEEE 1547 standard's enforcement, most DERs still employ the unity power factor control strategy, and the voltage capability of DERs has not been widely used or studied. Therefore, this study evaluates the different reactive control modes and ranks them based on the Voltage Regulation Index, Overvoltage Instances, Maximum and Average Voltages, and the impact on the distribution system PV hosting capacity. The analysis is performed on a modified IEEE 13 bus distribution system, through six hundred seconds of quasi-steady-state simulation with a second-time step size using a changing irradiance profile. The simulation is carried out with the CYME software. The simulation results show that the Volt- VAR (Vars Precedence) control mode provides the best performance. In contrast, the Unity Power Factor control strategy provides the worst performance for all selected metrics.