The Simulation Analysis And Experiment Research Of Short Circuit Fault In Photovoltaic Power Station

How to break fault current for the DC circuit breaker quickly and stably is the most important issue to be resolved in photovoltaic power station as well as in micro-grid. The existing photovoltaic power system has no uniform breaking standard when a fault occurs, so the study of the fault current response in the DC-side when the fault occurs is important for the design of the DC circuit breaker. Through simulation, this paper studies the failure response characteristics under constant power control strategy in the photovoltaic power station, laying the foundation of the protection in the photovoltaic power station.First, the paper analyzed and compared the application scope of different circuit topology of the photovoltaic power station And then, through the research of the photovoltaic lightning junction box hardware circuit, the method of current and voltage signals collecting is described in this paper. Combining with the hardware structure of the two-stage photovoltaic power station, the constant power control strategy is selected to design the whole simulation scheme of the photovoltaic power station.The equivalent circuit of single photovoltaic cell is studied, and the four-parameter model of PV module and a photovoltaic array is derived by mathematical analysis. Comparing the advantages and disadvantages of different maximum power algorithm, the improved maximum power algorithm is proposed. Through the study of LC type of grid-connected inverter circuit topology, we use a current PI decoupling control of the grid voltage compensation. Finally, this paper established a four-parameter model of the PV array, boost circuit model which uses an improved maximum power point tracking algorithm and grid-connected inverter model which adopts current PI decoupling control under the simulation environment.By the simulation of single photovoltaic cells, the maximum power point tracking of photovoltaic arrays and a grid-connected operation of the total system verified the accuracy of each model. By correcting the nameplate parameter of the photovoltaic modules obtained a photovoltaic array simulation model of non-standard test conditions. Then through the simulation of different types of short circuit fault in the photovoltaic power station obtained the DC-side short circuit fault response.Finally, building a 300W grid-connected PV systems laboratory platform to test short circuit fault at the outlet of the photovoltaic power station Comparing with the experimental data, the accuracy of the simulation results is verified and the design requirements of the technical parameters of Hybrid DC circuit breaker in photovoltaic power station are given.