The Research Of The Harmonic Voltage Contributions Allocation Of The Concerned Bus

With the rapid development of industry, the situation of harmonic pollution becomes increasingly serious in power system. Determining harmonic contribution is helpful to improve the initiative of harmonic customers, which is of great significance to improve the power quality of the system.Assessing Equivalent harmonic impedance accurately is the premise of studying harmonic contributions. This paper researches the fluctuation quantity method which is widely used in engineering to assess harmonic impedance. It is summarized that the effective data used to calculate the system harmonic impedance can not be filtered accurately by the fluctuation quantity method when the background harmonic voltage fluctuation is dominant. The defect has been verified through a lot of simulations. To solve the problem, this paper researched and applied kernel estimation with partial linear method. The method avoids the qualitative discussion about the fluctuation of which side of the points of common connection(PCC) is dominant. The quantitative results of the fluctuant background harmonic voltage can be obtained directly. Firstly, the method expanded background harmonic voltage at a moment in accordance with Taylor series. Then,to ensure accuracy of the calculation, on the basis of least sum of square error, the objective function considered the effective neighborhood of the moment and the influence of different error terms for different weights and used bandwidth controlling the range of neighborhood and each size of weight. Finally, the background harmonic voltage is solved by matrix operation. In addition, the result of the background harmonic voltage was simplified to make the operation faster without losing accuracy.A case study was conducted and the results indicated that the method is more effective compared with two improved fluctuation quantity methods.