A harmonic contribution partiton method of multiple harmonic sources considering the fluctuation of the background harmonic voltage is proposed. First

the system harmonic impedance is estimated by the dominant fluctuation filtering principle. Secondly

the background harmonic voltage is clustered and divided into different data segments by the mean shift algorithm according to the fluctuation of the background harmonic voltage. Finally

the harmonic contribution of each segment is estimated by the partial least squares method

and its harmonic weighted sum is calculated to obtain the final harmonic contribution. The method proposed is tested on an experimental circuit and an IEEE 13-bus test system. The results show that the method proposed is able to improve the accuracy of harmonic contribution partition

and effectively overcome the influence of background harmonic voltage fluctuation on harmonic contribution partition. This work is supported by National Natural Science Foundation of China (No. 51407150

No. 51307146) and Specialized Research Fund for the Doctoral Program of Higher Education (SRFDP) of China (No. 2013018410002).