Estimation of Power Output of Photovoltaic Systems based on Solar Irradiation, Statistical Models and Power Flow in Distribution Line

In this paper, the authors propose a method to estimate total power output of photovoltaic (PV) systems connected in the distribution network. Total power output of PV systems connected to the distribution line is estimated based on the observed solar irradiation, statistical model and power flow in the distribution line, where PV systems are connected. The proposed method is divided into low and high-frequency component estimations, which estimate output of PV systems down to second and minute resolution depending on the temporal resolution of power flow. Performance of the proposed method is evaluated based on simulations using real data from two Japanese demonstration projects. For the estimation of output of PV systems in the distribution line, simulation results show that the root mean square error (RMSE) of estimation varies between 4 and 14 percents (normalized by PV systems capacity) according to power flow temporal resolution, PV penetration level, distance between solar irradiation observation point and distribution line. Up-scaling model is also investigated. Theoretical evaluation results show that having one representative point in every 40km × 40km distribution network is the most suitable configuration for estimating PV systems output for overall power system.