A New Procedure for Determining Current Harmonic Contribution around an Operation Point at PCC Using Load Modelling Based on Crossed Frequency Admittance Matrix

Abstract:Today, one of the important issues of power quality (PQ) in power systems is the current harmonics. Increasing expansion of nonlinear loads at different parts of the electric network makes harmonic distortion flow through the network. This causes the network to have background voltage and current harmonic distortion and even affect on the PQ of linear load performance. Therefore, it is important to determine the harmonic contribution between load and network in distribution networks and industrial centers. In this paper, a new procedure for determining the current harmonic contribution around a quiescent point at the PCC is presented using load modeling based on crossed-frequency admittance matrix. The novelty of this paper is that, firstly, instead of using the harmonic Norton model of load, which has often been used in papers related to the harmonic contribution, it uses the crossed-frequency admittance matrix model, which is closed to actual load model; and secondly, considering the fact that a linear load has a diagonal form for its crossed frequency admittance matrix, the separation of harmonic contribution is made. To evaluate the proposed method, simulation was performed in three case studies using MATLAB software. In all three case studies, the results were close to the expected results.