Application Research On The Key Technology Of Xinao Zhangqianwu 40MW Grid-connected Photovoltaic Power Station

In view of the generation problems by making use of fossil energy that there exists environmental pollution and the increasing depletion of fossil energy,many governments have introduced policies to develop new energy power generation technology.As a kind of renewable energy,photovoltaic power generation has many characteristics,such as environmental protection and no pollution,rich resources,easy access,and so on,which has gained more and more attention and development.However,the current photovoltaic power generation and grid technology is not mature,photovoltaic grid connected will bring a series of adverse effects on the power system relay protection,stability and so on.Therefore,this paper did a deep research and analysis on the key technology of the Xinao Zhangqianwu photovoltaic power station grid connected.Aiming at the grid-connected characteristics of photovoltaic station,the equivalent model of the photovoltaic cell is given at first,and then the equivalent circuit of the photovoltaic cell was built in Matlab/Simulink.Then the output characteristics of photovoltaic cells was analyzed under different light illumination intensities and ambient temperature conditions,and made detailed instructions on the current classification of photovoltaic cells,the actual uses,and the advantages and disadvantages.Then,it was introduced in detail that the structure and mathematical model of the photovoltaic system.Aiming at the problem of low voltage ride-through,the LVRT curve was given.A joint control strategy was proposed,which combined the improved control circuit and DC discharge load circuit,to inhibit the inverter over-voltage,over current effectively and provide a strong reactive power support.The simulation results verified its effectiveness.The overall structure,electrical design system and grid connected pattern of the Xinao Zhangqianwu photovoltaic power station were outlined,and presented its structure diagram and electrical wiring diagram.Then,the PV power dispatching automation and its remote information transmission mechanism were introduced in brief.On this basis,the design and configuration were made aiming at the communication network,electric energy metering device,power angle measurement system and optical power prediction system.Aiming at the design of the relay protection,the electrical main wiring and protection configuration scheme of the photovoltaic power station were given at first.Combined with the characteristics of the photovoltaic power station,short-circuit current calculations were made for different fault points set in the photovoltaic power station on the basis of the traditional design method of relay protection.Then adjusting all relay protections respectively,including 35 kV grounding transformation and arc suppression coil protection,35 kV substation protection,35 kV SVG protection and PV line protection.Then,the influence of photovoltaic grid connected on the power system was analyzed,and the adaptive adjustment was made to the protections of the adjacent lines and substations.