Modeling Of Photovoltaic Power Generation System Based On Parameter Identification And Analysis Of Its Influence On Distribution Network

With the development and utilization of solar energy,the installed capacity of photovoltaic continues to increase,and the large-scale photovoltaic power grid connection,leading to the shortcomings of solar power generation continue to appear.Due to the randomness and intermittence of solar power generation,its large-scale grid connection will have a huge impact on the power quality of the grid.The detailed photovoltaic electromagnetic transient model is not welcomed by researchers because of its complex calculation and long simulation time.Some simplified photovoltaic general models emerge at the historic moment,but its control parameters of the inverter have not been tested and verified by the actual test.The simulation analysis results based on this model will have a large error with the actual situation,especially when photovoltaic power generation is connected in large scale,the error accumulation causes the model can not reflect the real situation,and the simulation results obtained through this model can not support the actual operation of the distribution network.Therefore,this paper proposes a method to obtain the key parameters of the simulation model by selecting the appropriate photovoltaic model and identifying its inverter control parameters,and then accurately analyze the photovoltaic grid connected system.The main work of this paper is summarized as follows:(1)The power generation principle of photovoltaic cell is described;The common methods of MPPT control and PLL control are introduced in detail;the photovoltaic inverter and its control model are studied,and its basic topological structure and control strategy are understood;the differences and applicability between the detailed photovoltaic power generation model and the simplified model are compared and analyzed.The simplified model with simple structure and rapid simulation is selected as the analysis model of photovoltaic access distribution network.(2)The sensitivity analysis of parameters to be identified carried out;according to the sensitivity analysis results,the large disturbance and small disturbance conditions are designed to collect the measured data;based on the adaptive inertia weight particle swarm optimization algorithm,the control parameters of the simplified model are identified many times by using multiple groups of measured data;the optimal value is extracted from multiple identification results by error calculation;the simplified photovoltaic model with verified inverter control parameters is obtained.(3)A 10 KV side distribution network is selected,and the photovoltaic model with identified control parameters is incorporated into the power grid for operation.After photovoltaic access to the distribution network,the influence of the contradiction between photovoltaic access location,access capacity,access mode,light intensity and load level on the node voltage is simulated and analyzed.At the same time,the feasibility of photovoltaic inverter regulating the node voltage by controlling reactive power is analysed,some theoretical guidance for the influence of photovoltaic access on the voltage quality of distribution network and the research of voltage regulation by using inverter to control reactive power is provided.