Power Prediction Model of Grid-Connected Photovoltaic and Power Flow Analysis

Grid-connected photovoltaic output forecasting and its impact on distribution network power flow is the research focus of new energy development. To solve this problem, this paper introduces a solar radiation model of weather forecasting system and uses the diffuse radiation fitting model to modify it so that it could make short-term prediction on photovoltaic output by the cloud type forecasting information obtained from meteorological department. Based on the output of solar radiation and the distribution network constraints, a new algorithm was proposed for power flow calculation of the weekly meshed distribution network with distributed photovoltaic. The algorithm describes the distribution network as two parts: loop and radiation, which were respectively solved by Gauss-Seidel and Back/forward sweep methods. To calculate the power flow, two methods were used alternatively. At last, a 28 point example was solved using the proposed algorithm and the results show that the photovoltaic power prediction model could accurately predict output and this algorithm has clear advantages in computing speed as well as the speed of convergence.