Integrated Volt/Var Control Method for Voltage Regulation and Voltage Unbalance Reduction in Active Distribution Networks

Abstract

The emergence of distributed generation such as solar systems has introduced new challenges in distribution networks that are becoming more apparent with increasing penetration levels. The time mismatch between peak load and peak generation can make voltage levels in distribution networks swing towards extreme limits during a day. Distribution network service providers are struggling to cater for new distributed generation installations while ensuring that the quality of steady state supply voltage meets stipulated requirements. The segregation between medium and low voltage networks in control strategies may result in unnecessary or worse, opposing control actions leading to voltage issues and control on one side of the distribution network influencing the other. By developing an efficient volt/var control method, the steady state voltage level and voltage unbalance in a comprehensive distribution network can be controlled simultaneously. This paper analyses voltage issues and volt/var control in medium and low voltage networks as a whole, unabridged problem. This paper proposes a pragmatic and effective volt/var control method that addresses voltage regulation and voltage unbalance simultaneously using existing infrastructure. The proposed control method is implemented on three types of representative Australian distribution networks and results obtained demonstrate that the proposed volt/var control can simultaneously manage voltage level and voltage unbalance whilst reducing the number of tap change operations and maximizing solar penetration.

A Hierarchical Multi-Stage Coordination of Inverters for Voltage Control in Active Distribution Networks with a µPMU-PDC

“…By considering ΔV2 as a voltage drop across Z2 and ignoring the impact of the phase difference between V1 and V2 on voltage regulation, the relationship between the voltage at B1 and B2 can be explained as (3).…”

“…Each resource block is 0.5 ms long and a path loss exponent of three is considered. The path loss is modeled as (d/d0) 3 , where d is the actual distance between the PMU and PDC and d0 is the reference distance. The channel gain is inversely proportional to this path loss.…”

“…However, with the large integration of DERs and the consequent reverse power flow, voltage regulation has emerged as a major concern for distribution network operators (DNOs), due to voltage violations occurring outside the permitted range (e.g., 0.95 pu < v bus < 1.05 pu, recommended by ANSIC84.1-2016 [1] and IEEE 1547-2018 [2] standards). In response, various functions have been integrated into the inverters of DERs, enabling them to function as smart inverters (SIs) and ensure acceptable power quality and reliability of supply [3]. However, these functions typically operate based on local information/measurements and respond individually.…”

Optimal Reactive Power Dispatch in Electric Transmission Systems Using the Multi-Agent Model with Volt-VAR Control

“…Electric utilities adopt the patented VVC control through the VVC algorithm, continuously monitor voltage magnitudes throughout the system, and make decisions based on voltage readings where substation capacitors and field capacitors are disturbed by simple rules concerning the capacitor. The control trips when the voltage drops below the voltage levels contemplated as permissible and shuts down when it exceeds the upper limit of the same permissible level, correcting in both cases [7,28].…”

Cluster Partition-Based Voltage Control Combined Day-Ahead Scheduling and Real-Time Control for Distribution Networks

“…Additionally, an adaptive droop control strategy is also proposed to deal with voltage fluctuation. To carry out voltage regulation, an effective volt/var control method is proposed in [5]. This method is implemented on a practical Australian feeder, and the effectiveness of the method is proved in regulating the voltage level.…”