Impact of three-phase single-stage photovoltaic (PV) system interfaced with distribution network on load modeling

This paper builds a dynamic model of three-phase single-stage photovoltaic system interfaced with distribution network, and its external characteristics is studied. The research results show that the model frame of the generalized load model of distribution network which contains three-phase single-stage photovoltaic system can be obtained by adding a variable active power source to the fictitious bus of conventional synthesis load model (SLM). Seven parameters to be identified, i.e. three characteristic parameters of the photovoltaic array, the capacity of the electric capacitor in parallel with photovoltaic array, the proportion of three-phase single-stage photovoltaic system relative to pure load, the proportion amplification constant and the integral amplification constant of voltage regulator should be added to that of SLM. A parameters identification strategy is proposed. Firstly, the loads are aggregated. Then, the low-sensitive parameters are fixed as the aggregated values, while high-sensitive parameters are identified near the aggregation values by genetic algorithm. The characteristic fitting capability and the generalization capability of the proposed generalized load model is validated by a simulation example.