Recognition of harmonic sources in distribution network using fractal analysis

One of the most important power quality problems is harmonic pollution in power system. In recent years there has been an increase in voltage and current distortion in the distribution network due to the extensive use of power electronic and computer controlled devices. In this paper, using fractal analysis the source of harmonic pollution has been identified in a radial power system distribution network. The fractal technique provides both time and spectral information of the nonlinear load harmonic patterns. The network is simulated using EMTP/ ATP software. Simulation results have been presented which show that the proposed method can successfully identify the location of the harmonic source in case of a single harmonic source and location of dominant source of harmonic pollution in case of multiple harmonic sources in the system.

I. Introduction

The presence of voltage and current components at frequencies other than the fundamental one is harmful to the equipment connected in the power system network. Harmonics can be produced by the loads only, by the source only or both by the source and load. The location of nonlinear load when a single nonlinear load is present and also location of the dominant source of harmonic pollution when more than one nonlinear loads are present can be detected by observing the fractal dimensions of the line currents of each node.