Model-Free Optimal Voltage Phasor Regulation in Unbalanced Distribution Systems

Abstract

The proliferation of phasor measurement units (PMUs) into electric power distribution grids presents new opportunities for utility operators to manage distribution systems more effectively. One potential application of PMU measurements is to facilitate distribution grid re-configuration. Given the increasing amount of Distributed Energy Resource (DER) penetration into distribution grids, in this work we formulate an Optimal Power Flow (OPF) approach that manages DER power injections to minimize the voltage phasor difference between two nodes on a distribution network to enable efficient network reconfiguration. In order to accomplish this, we develop a linear model that relates voltage phase angles to real and reactive power flows in unbalanced distribution systems. Used in conjunction with existing linearizations relating voltage magnitude differences to power flows, we formulate an OPF capable of minimizing voltage phasor differences across different points in the network. In simulations, we explore the use of the developed approach to minimize the phasor difference across switches to be opened or closed, thereby providing an opportunity to automate and increase the speed of reconfigurations in unbalanced distribution grids.

A Comprehensive Multi-Period Optimal Power Flow Framework for Smart LV Networks

“…Explicit ZIP coefficients for commercial, residential and industrial loads have been proposed for conservation of voltage reduction (CVR) studies in unbalanced distribution systems [19], though this customer variety is only found in MV systems. A common ZIP load structure has even been employed in studies following model-free approaches of distribution system optimization, see [20] for example (phasor regulation strategy), with the work assuming the simplest form of an unbalanced system. Comparisons between different load models have been performed, though these are either on a purely technical level, i.e., behavior of single, standalone load [21], or comparisons between the standard ZIP model and different approximations of it [22].…”

A novel soft island in integrated distributed generation to improve utility grid safety and stability at different modes of operation

“…T hese two porosity sets f or a closedloop behaviour by previous scalars p i , p j along z x(t) = x i=1,2.. (22) x(t), y(t) can be obtain by equations (23), (24) respectively x…”

Phasor-Based Control for Scalable Integration of Variable Energy Resources

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