The power quality analysis of the PV access system based on DIgSILENT software

In recent years, photovoltaic power generation has been widely used due to its clean, pollution-free, low-cost features. When PV is connected to the power grid, there is a dynamic interaction between the inverter control loop and the passive components, so that the amplitude of the grid-side voltage and current harmonics continues to be amplified and severely distorted. This phenomenon has a great impact on the power quality of the power grid. In view of this phenomenon, this paper takes the 60MW agricultural photovoltaic hybrid power station project of Fuxiejie Town, Yangxin County of China Power Investment Corporation as an example, and simulates PV into PV nodes and harmonic sources, and builds a grid-connected photovoltaic system model on the DIgSILENT simulation platform. On this basis, the simulation analysis of the harmonic voltage, current and voltage drop of the internet point was carried out. Then according to the national standard GB/T 19964-2012 "Technical Regulations for Photovoltaic Power Plant Access Power System", GB/T 12325-2008 "Power Quality Supply Voltage Deviation" and GB/T 14549-93 "Power Quality Public Power Grid Harmonics", comparing the simulation results with the allowable values specified by the national standard, the power quality of the Yangxin County power grid was analyzed. The results show that when PV power plants have the greatest impact on the power grid (maximum PV output), voltage deviations and harmonics at various points of the Yangxin County power grid are lower than the allowable values and meet the requirements.