Roof power station refers to the use of plant, public buildings, residential and other roof resources development of photovoltaic power station.  This type of power plant size is limited by the effective roof area, the installed scale is generally in a few kilowatts to dozens of megawatts;  Power generation to encourage local consumptive, directly feed into the low voltage distribution network or 35 kv and below the high voltage power grid;  Component orientation, tilt angle, and shadow shading vary.  This type of power plant is the main form of distributed photovoltaic applications,mainly concentrated in the central and eastern and southern regions of China.