Photovoltaic: is the abbreviation of solar power system (Solar power system). It is a new type of power generation system that uses the photovoltaic effect of solar cell semiconductor materials to directly convert solar radiation energy into electrical energy. It has independent operation and There are two ways of grid-connected operation. At the same time, solar photovoltaic power generation systems are classified, one is centralized, such as large-scale northwest ground photovoltaic power generation systems; the other is distributed (with> 6MW as the boundary), such as industrial and commercial factory roof photovoltaic power generation systems, residential roof photovoltaic power generation systems.