Calculation of Neutral Grounding Method and Grounding Transformer Capacity for Photovoltaic Power Plants

China is the world’s second largest economy and the country with the largest industrialization scale, as well as one of the world’s largest energy consumers. China uses fossil fuels such as coal as its main energy source, and fossil fuel combustion is the main source of air pollution in China. Therefore, the development of renewable energy sources such as solar energy, wind energy, and tidal energy has become a requirement of China’s 14th Five Year Plan, with the focus on internal circulation and the construction of domestic and international dual circulation. The grounding method of the neutral point directly affects the insulation level of electrical equipment and the safety, reliability, and power supply continuity of photovoltaic power plants. The installation scale, grid connection voltage level, single-phase grounding fault current, protection device sensitivity, and overvoltage level of solar photovoltaic power stations vary, and the grounding method of the neutral point varies. The article discusses the application of various neutral grounding methods in solar photovoltaic power plants, and then takes a photovoltaic power plant in Zhangbei County, Zhangjiakou City, Hebei Province as an example to study the capacity calculation method of grounding transformers for a 50 MW level large-scale solar photovoltaic power plant. This can provide reference for the selection of grounding transformer capacity for large-scale grid connected photovoltaic power plants.