In case of fluctuation of the background harmonic voltage and variation of the system impedance

it is difficult for the traditional harmonic responsibility division method to assess the harmonic responsibility accurately. In this case

a kind of multi-harmonic responsibility division method considering the background harmonic voltage fluctuation and impedance variation is proposed. Firstly

the data segment with small background harmonic voltage fluctuation is screened out by using the similarity measure principle.Then the scatter diagram of harmonic voltage and harmonic current data set at common connection point is set up. The OPTICS algorithm is used for clustering so that the sampling data can be calssified into different clusters in accordance with impedance of the system. Finally

the multi-harmonic responsibility division is performed by the use of complex domain partial least-square method for the data of different clusters. It is verified by the simulation analysis that the proposed method can reduce the influence of background harmonic voltage fluctuation and variation system impedance on the harmonic responsibility division.