Technical cost of PV-STATCOM applications

In daytime operation the power converter of a photovoltaic installation is generally used below its rated power. It could then provide reactive power support to the grid. This operation is called PV-STATCOM. This work provides an evaluation of the technical cost of operating a PV-STATCOM during daytime. This technical cost is due to the need of buying active power from the grid to supply extra losses when providing reactive power support to the grid. To illustrate, a 1.5 MWp PV farm is modeled in Matlab/Simulink toolbox SimPowerSystems. Losses from all the PV-STATCOM components are evaluated (converter, tie reactor, filter and step-up transformer). The daytime technical cost can reach up to 5.0% of the system rated capacity with the power converter being the main source of losses in PV-STATCOM operation. Finally, the reactive power support capability map is obtained as a function of the solar irradiance.