Harmonic Characterization of Medium-Voltage Distribution Networks with Photovoltaic Generation

With a large number of photovoltaic systems connected to the power grid, the harmonic components of medium-voltage distribution network are increasing. In order to reduce the impact of harmonics on distribution network and electrical equipment, it is necessary to study the harmonics generated by photovoltaic generation and the distribution of harmonics in medium-voltage distribution networks. Firstly, the process of photovoltaic generation is introduced. Next, the mechanism of harmonic generation in inverter is analyzed, and the distribution of harmonic in low-voltage distribution network, common connection point and distribution lines are analyzed. Finally, a simulation model is built in MATLAB Simulink environment to simulate and analyze the harmonics of the low-voltage side of the step-up transformer, the common connection point of the photovoltaic generation and the lines of the medium-voltage distribution network. The analysis and simulation results provide the basis for the subsequent improvement scheme and the improvement of relay protection of distribution network.