Research On Quantitative Estimation Methods Of Harmonic Source

With the development of science, power technology gets rapid expanding and agreat variety of electronic devices have been used in electronic power system whichinclude many nonlinear devices. They cause power quality problems. Harmonic is animportant index of the power quality, it attracts attention because the harmonic notonly will affect the economy，but also threat the safety of power system. Find out theharmonic sources and divide governance responsibility reasonably have importantsignificance for the whole power system. Find method of assessing the harmonicemission level and research the rational harmonic responsibility division method isvery necessary.Clarify the harmonic pollution is the common responsibility of power supplydepartment and user. In recent years, there are many methods proposed by scholars ofthe world. These methods can be roughly divided into two categories namedqualitative identification and quantitative estimation. The early technology ismainly harmonic qualitative identification, which can only determine the mainharmonic source between power supply side and user side. Thequantitative estimation can calculate the harmonic pollution level though theharmonic impedance calculation. This paper studies and analyzes the variousmethods, points out the reasonableness and deficiency, and verify some theorythrough the simulation.After many studies, this paper presents a method of harmonic responsibilitydivision based on latent root estimator. It can estimate the pollution level ofharmonic source. The basic idea is that divide the whole system into the supply anduser side which are respectively represented by Thevenin and Nortonequivalent circuit and build regression model. Through the measurement at the pointof common coupling obtain harmonic voltage and current signals, and then calculatethe regression coefficients by latent root estimator, so we can calculate the harmonicimpedances and estimate the pollution level of harmonic source. At the end of thispaper, experiments are carried out by simulation software MATLAB and comparewith other methods to verify the method based on latent root estimator is superior.