The Research Of Analysis Method On Multi-harmonic Sources Harmonic Responsibilities

With the rapid development of economy and the improvement of people's living standards improved significantly,obvious changes have taken place in electric loads.Especially in recent years,with the rapid rise of power electronics technology,a large number of power electronics equipments are widely applied to all aspects of production and life,which improves the production efficiency and quality of life greatly and are praised by all walks of life.However,the drawbacks are gradually exposed with the increasing number of power electronic devices and harmonic will inject power grid during the actual operation.As each harmonic source will produce a certain harmonic,if there are lots of harmonic sources in the grid,massive harmonics will cause deterioration of power quality and even endanger the operation of power grid.Due to the lack of effective supervision measurements when users injected harmonic into grid;furthermore,the suppression of harmonic can't not only bring benefits but also increase equipment investment,so users are not interested in harmonic suppression.And harmonic problem is getting worse.At the same time,the way by switching out the customer by force to limit excessive harmonic injection is clearly contrary to the spirit of the power market reform.To control the hazards of harmonic more effectively,a lot of experts have research this question for many years,the “rewards and punishment scheme” was put forward ultimately.In this scheme,if users absorb harmonic,there is much reward;otherwise,users should be punished.Around this scheme,experts have made much beneficial exploration in the field of harmonic responsibility partition.Researches mainly analyze harmonic responsibility of the user side and the grid side at the point of common coupling and single harmonic source instead of multiple harmonic sources.In practice,however,the situation of multiple harmonic sources is more common.So it is necessary to quantify harmonic responsibility of multiple harmonic sources.At present,this aspect needs to study thoroughly and also is an important direction for future research.This paper is focused on harmonic responsibility analysis methods of multiple harmonic sources.Multi-harmonic source model and grid component models are established.harmonic voltage evaluation index and harmonic current evaluation index are presented and at last harmonic voltage evaluation index is regarded as harmonic responsibility evaluation index.For a certain harmonic frequency,harmonic responsibility of a single harmonic source can be expressed the ratio of the harmonic voltage generated by the harmonic source on the total harmonic voltage of the observation bus.This paper summarizes several methods,such as least square method,weighted least square method,partial least square method,complex least square method and robust complex least square method,the advantages and disadvantages are analyzed.Finally,the total least square method is used to quantify harmonic responsibility for the first time.When the total least square method is adopted to establish harmonic responsibility analysis function,both harmonic voltage measurement error and harmonic current measurement error are considered.However,traditional methods only consider harmonic voltage measurement without considering harmonic current measurement error.Finally,the validity and superiority of total least square method are verified by theoretical proof and simulation analysis.