An improved harmonic resonance mode analysis method for distribution power grid

Harmonic resonance endangers seriously safe and reliable operation of power grid and an appropriate resonance harmonic analysis method is of great importance. The traditional mode analysis method is a kind of main method to analyze harmonic resonance of power grid so to obtain various harmonic information such as resonance frequency, maximum excitation node and observation node as well as participation factor. However, its calculation efficiency is lower and has no way to judge accurately the maximum excitation node in the harmonic resonance of the distribution power grid. The improved mode analysis method proposed in this paper combines the frequency spectrum analysis with the traditional mode analysis method, and the condition of whether the harmonic resonance could occur at the determined excitation node at resonance frequency is added. Taking the distribution power grid in Bonan Oil area of Shengli Oilfield as an example, this paper analyzes the harmonic resonance of distribution network by using traditional mode analysis method and improved mode analysis method respectively. By comparing the analysis results of the two methods, the superiority of the improved mode analysis method is verified. The analysis of harmonic resonance of distribution network in Bonan Oil area shows that the improved mode analysis method proposed in this paper can accurately determine the harmonic resonance frequency and the highest excitation node of distribution network, while the traditional mode analysis method could not accurately judge the highest excitation node. In addition, the calculation time of the improved mode analysis method is only 17% of that of the traditional mode analysis method, which greatly improves the analysis efficiency.