SMA Solar Technology AG
2 Design of PV Farms
Technical Information
IPC_STP-TI-en-14
5
2 Design of PV Farms
2.1 Typical PV Farm with Central PV Farm Control
Decentralized PV farms must be able to control the flow of reactive power. It is not enough for each inverter to comply
with the characteristic specified by the grid operator because all of the equipment (cables, transformers, switching
equipment, etc.) has an influence on the characteristic curve of the PV power plant as a whole.
Figure 5: Example of a Q(V) specified by the grid operators
This is why the central PV farm control records the most important grid values at the grid-connection point and compares
them with the characteristic curve provided by the grid operator. When deviations occur, a corrected uniform setpoint for
reactive power is transmitted to the inverters which then ensures that the required characteristic is achieved.
Figure 6: PV farm with central PV farm control
