Independent Component Analysis for Distortion Estimation at Different Points of a Network with Multiple Harmonic Sources

Abstract

The analysis of the harmonic distortion contribution on the PCC, traditionally, quantifies only the contribution from the load side (or distributed generation) and from the main source side. However, it is necessary to quantify the individual contributions of the different harmonic sources present in the system at a chosen point. For this it is necessary to estimate the transfer impedances from each source to the chosen point. This work presents a methodology to estimate the transfer impedance matrix Zk of the system using the Independent Component Analysis (ICA) technique. The methodology uses the currents and voltages acquired at the PCCs of each source and at the chosen point. The proposed method for estimating Zk is a passive method that explores the natural variations of harmonic sources. With Zk and the harmonic current injections of each source (estimated by the ICA) it is possible to identify the individual harmonic contributions at the chosen point. Due to the time-varying nature of harmonic distortion the method is intended for periodical estimations. The performance and effectiveness of the proposed method are demonstrated by simulating a Benchmark test system to evaluate the harmonic contribution.