Modeling Of Large Scale Photovoltaic Power Station And Research On Its External Characteristics

With the increasing installed capacity of photovoltaic power generation system, PV power stations which connect to the grid will inevitably produce a series of impacts, and bring many challenges to development plan of the grid. To meet the needs of large-scale application of PV power station, we need to establish the equivalent simulation model of large-scale PV power station, which aim at research and analysis the properties of PV power station.Firstly, it studies on modeling approach of the various components of the PV power station, including PV array, PV grid-connected inverter, transformer and transmission cable line. Combined with the actual project in Inner Mongolia, the detail equivalent model of PV power station is established. For the higher requirement to simulation sampling rate, it leads to long time consuming when the detail equivalent model runs. Thus, it simplifies the detail model to solve the problem. The new model which uses controlled source instead of switch device model called average equivalent model. Verify the correctness of the equivalent model and its control method, the results show that the equivalent model could be able to accurately demonstrate the outside features of large-scale PV power station.As a result of majority of large-scale PV power stations, which built in the desert, is generally faced with long distance transmission problem. So it pays more attention to the external characteristics of PV power station as a whole power generation unit. Base on the aggregation modeling principles, it research on the modeling method of equivalent aggregation model. Combined with the detail model, the equivalent aggregation model of large-scale PV power station is established. Verification by simulation analysis, the equivalent aggregation model can accurately demonstrate the external characteristics and transient performance of PV power station.Take the equivalent aggregation model of large-scale PV power station which connects to the grid for sample, it adopts Matlab to simulate the operation of PV power station under different conditions. Analysis of the various effects on the grid, the results show that the random fluctuations of output power are the root causes of the stability problems. Lack of reactive power output and frequency modulation capacity is another problem to the large-scale PV power station. Thus, PV power station should equip with reactive power compensation equipment. And with the construction of traditional power stations can solve the system peak shaving and frequency modulation problems.