Estimating the Frequency Coupling Matrix from Network Measurements

TL;DR

This paper introduces methods to estimate the frequency coupling matrix (FCM) of power converters directly from network measurements, enabling better harmonic modeling and analysis in power systems.

Contribution

It presents a novel harmonic reduction theorem, an estimation approach from PMU data, and an efficient online algorithm for FCM estimation.

Findings

Low estimation error under noisy conditions

Effective harmonic modeling from network data

Novel harmonic reduction theorem for unobservable network parts

Abstract

Power converters are present in increasing numbers in the electric power grid. They are a major source of harmonic currents and voltages, which can reduce power quality and trip protection devices. The frequency coupling matrix (FCM) is a general technique for modeling converter harmonics. It can be obtained through experimental characterization or, given a converter's internal parameters, direct calculation. In this paper, we estimate FCMs from network measurements. We give a novel harmonic reduction theorem for computing equivalent, virtual FCMs for unobservable portions of a network. We estimate FCMs and harmonic line admittances from PMU measurements, and give an efficient online version for the FCM problem. We test our approaches on a numerical example, and show that the estimation error is low under noisy observations.