Analytical Voltage Sensitivity Analysis for Unbalanced Power Distribution System

TL;DR

This paper introduces a low-cost analytical voltage sensitivity method for unbalanced power distribution systems, enabling efficient stochastic analysis and validation against classical load flow simulations.

Contribution

It develops a novel analytical approximation for voltage sensitivity in unbalanced radial systems, validated for various load configurations and significantly reducing computational complexity.

Findings

Method achieves high accuracy in voltage sensitivity estimation.

Computational complexity is reduced to O(1) from O(n^3).

Validated against IEEE 37 bus system simulations.

Abstract

Large scale integration of distributed energy resources and electric vehicles in a transactive energy environment present new challenges in terms of voltage stability and fluctuations in a power distribution system. The impact of different level of DER/EV penetration on the voltages across the network is typically quantified through voltage sensitivity analyses. Existing methods of voltage sensitivity analysis are computationally expensive and prior efforts to develop analytical approximation lacks generality and have not been effectively validated. The objective of this work is to provide a new analytical method of voltage sensitivity analysis that has low computational cost and also allows for stochastic analysis of voltage change. This paper first derives an analytical approximation of change in voltage at a particular bus due to change in power consumption at other bus in a radial three phase unbalanced power distribution system. Then, the proposed method is shown to be valid for different load configurations, which demonstrates its generality. The results from our analytical approach is validated via classical load flow simulation of the test system based on IEEE 37 bus network. The proposed method is shown to have good accuracy, and computation complexity is of order O(1), compared to O(n3) in classical sensitivity analysis approaches.