During the selection

design and capacity calculation process of reactive power compensation device of distributed photovoltaic power stations

the significant difficulties for engineering designers due to the lack of relevant design schemes

in case of participation of photovoltaic inverters in grid regulation

are required to be considered. Regarding this issue

the reactive loads and reactive power sources of the distributed photovoltaic power stations are described firstly and the specific calculation formulas are given respectively. Then

the concept of leftover natural reactive power load is proposed

and compensation capacity calculations based on grid reactive power balance are performed at such three different operating conditions as lagged phase operation

leading phase operation and non participation in grid regulation and the general calculation formula for compensation capacity is given. After that

the specific schemes for selecting reactive power compensation devices and corresponding capacity configurations under different situations are analyzed and discussed respectively

thus providing a design and calculation method for reactive power compensation device in distributed photovoltaic power plants. Finally

some suggestions for harmonic control and installation location selection of reactive power compensation device are proposed so to provide certain references for the engineering designers.