The harmonic calculation model of non-linear load

Widespread usage of non-linear loads has caused an essential problem of harmonic pollution in the power system. Harmonic distortion will do enormous harm to the power system. Using numerical computation method to calculate and predict the harmonic propagation is contributes to design useful harmonic management schemes. The harmonic calculation model of non-linear load is vital to the harmonic computed result. In some critical conditions, using different models to represent the load characteristic will get distinctly different results. Model type and parameter errors are two important factors that affect the calculation accuracy. In this paper, the linear and non-linear parts of the non-linear load are modelled separately and then use their combination to represent the non-linear load. This paper introduces a number of practical models, and compare how different frequency response characteristic caused by the change of operation condition affects the harmonic computed results. Thus, the paper´s results are available as a reference for other researchers in choosing an appropriate model.