Using Effective Generator Impedance for Forced Oscillation Source Location

TL;DR

This paper introduces a systematic, model-agnostic method for locating forced oscillation sources in power systems by analyzing generator admittance and current source characteristics, validated through simulations.

Contribution

It develops a generator admittance-based approach to distinguish source from nonsource generators without relying on strong assumptions.

Findings

Method effectively identifies oscillation sources in test systems.

Approach is robust against measurement noise and parameter uncertainties.

Validated on WECC 179-bus system simulations.

Abstract

Locating the sources of forced low-frequency oscillations in power systems is an important problem. A number of proposed methods demonstrate their practical usefulness, but many of them rely on strong modeling assumptions and provide poor performance in certain cases for reasons still not well understood. This paper proposes a systematic method for locating the source of a forced oscillation by considering a generator's response to fluctuations of its terminal voltages and currents. It is shown that a generator can be represented as an effective admittance matrix with respect to low-frequency oscillations, and an explicit form for this matrix, for various generator models, is derived. Furthermore, it is shown that a source generator, in addition to its effective admittance, is characterized by the presence of an effective current source thus giving a natural qualitative distinction between source and nonsource generators. Detailed descriptions are given of a source detection procedure based on this developed representation, and the method's effectiveness is confirmed by simulations on the recommended testbeds (eg. WECC 179-bus system). This method is free of strong modeling assumptions and is also shown to be robust in the presence of measurement noise and generator parameter uncertainty.