A Zonal Volt/VAR Control Mechanism for High PV Penetration Distribution Systems

TL;DR

This paper introduces a zonal Volt/VAR control scheme for high PV penetration distribution systems, enabling independent voltage regulation in weakly coupled zones to improve speed and effectiveness.

Contribution

It develops a novel clustering method to divide feeders into zones and implements zone-specific control for better voltage regulation with PV inverters.

Findings

Maintains voltage within limits effectively.

Faster control response than centralized methods.

Successfully tested on a real distribution feeder.

Abstract

This paper presents a zonal Volt/VAR control scheme that coordinates Photovoltaic (PV) inverters for providing voltage regulation on 3-phase unbalanced distribution feeders. Voltage sensitivity studies are conducted to uncover the dependency between nodal voltage changes and the reactive power injections at nodes with smart PV inverters. A fast incremental clustering method is developed to divide the distribution feeder into weakly coupled zones based on correlations of nodal voltage sensitivities. Because each zone is weakly coupled, voltage of each zone can be controlled independently. Thus, in each zone, a rule-based voltage controller will dispatch PV smart inverters to provide reactive power control for correcting the over/under voltages. An actual distribution feeder in North Carolina is used as a test bed. Simulation results show that the proposed zonal based Volt/VAR control mechanism can maintain the voltage in the distribution system within limits and solves faster than the centralized controller.