Optimal Voltage Regulation of Unbalanced Distribution Networks with Coordination of OLTC and PV Generation

TL;DR

This paper presents a convex optimization framework for coordinating PV inverter reactive power and tap operations in unbalanced distribution networks, significantly improving voltage regulation and reducing over-voltage issues.

Contribution

It introduces a novel linearization method that convexifies the coordination problem, enabling efficient optimization for unbalanced systems.

Findings

Significant reduction in voltage deviations.

Effective mitigation of over-voltage problems.

Improved voltage imbalance control.

Abstract

Photovoltaic (PV) smart inverters can regulate voltage in distribution systems by modulating reactive power of PV systems. In this paper, an optimization framework for optimal coordination of reactive power injection of smart inverters and tap operations of voltage regulators for multi-phase unbalanced distribution systems is proposed. Optimization objectives are minimization of voltage deviations and tap operations. A novel linearization method convexifies the problem and speeds up the solution. The proposed method is validated against conventional rule-based autonomous voltage regulation (AVR) on the highly-unbalanced IEEE 37 bus test system. Simulation results show that the proposed method estimates feeder voltage accurately, voltage deviation reductions are significant, over-voltage problems are mitigated, and voltage imbalance is reduced.