Adopting Dynamic VAR Compensators to Mitigate PV Impacts on Unbalanced Distribution Systems

TL;DR

This paper introduces an optimized control and placement strategy for Dynamic VAR Compensators in distribution systems, improving voltage regulation amid high renewable penetration by surpassing traditional IEEE standards.

Contribution

It proposes a multi-objective optimization framework and supervisory control strategies to enhance DVC performance beyond IEEE Std. 1547 control schemes.

Findings

Reduces voltage variations more effectively than standard VV-C

Optimizes DVC placement and dispatch for various operating conditions

Demonstrates improved voltage stability in IEEE 123-bus system simulations

Abstract

The growing integration of distributed energy resources into distribution systems poses challenges for voltage regulation. Dynamic VAR Compensators (DVCs) are a new generation of power electronics-based Volt/VAR compensation devices designed to address voltage issues in distribution systems with a high penetration of renewable generation resources. Currently, the IEEE Std. 1547-based Volt/VAR Curve (VV-C) is widely used as the local control scheme for controlling a DVC. However, the effectiveness of this scheme is not well documented, and there is limited literature on alternative control and placement schemes that can maximize the effective use of a DVC. In this paper, we propose an optimal dispatch and control mechanism to enhance the conventional VV-C based localized DVC control. First, we establish a multi-objective optimization framework to identify the optimal dispatch strategy and suitable placement for the DVC. Next, we introduce two supervisory control strategies to determine the appropriate instances for adjusting the VV-C when the operating condition changes. The outlined scheme comprises two primary stages: time segmentation and VV-C fitting. Within this framework, each time segment aims to produce optimized Q-V trajectories. The proposed method is tested on a modified IEEE 123-bus test system using OpenDSS for a wide range of operating scenarios, including sunny and cloudy days. Simulation results demonstrate that the proposed scheme effectively reduces voltage variations compared to the standard VV-C specified in IEEE Std. 1547.