Design Of Power Generating System In30MWp Photovoltaic Grid-connection

As the nonrenewable energy sources gradually run down, to develop the renewable energy sources has become an inevitable trend, in the new typed green renewable energy sources, the solor power is safety and reliable and it has non-pollutant to let out. At present the system of photovotaic grid-connected generate electricity is a hotspot resarch, Grid inverter control technology is the key to power generation, whose main function is to transmit efficient power to the common power grid.The output characteristic of the solor power cells plate are studied, with using the PVsyst software to simulate and analyse the influences of the cells plate efficiency by the temperature, light intensity, series and parallels resistance and losses, and why the hotspot effect would appear is reviewed, then to reduce the hotspot effect that some measures are given, before the project is carried out, the optimum direction angle, lean angle and distance should be calculated to ensure that there is no shade, last the condition of the project cable installation, flow confluence process are summarized and a series of debugging for the cells are done.According to the grid request, on th basis of practical condition to survey and choose a suitable inverter which is three phase full bridge inverter, in order to cut down the multistage booster bringing excess losses, single-stage booster is adopted, which leaves out the traditional DC-DC link, at this moment, another two functions are completed by the inverter, which are MPPT and SVPWM, an algoritm is put forward, which is based on perturbation observation of INC method to track the MPP, then make the tracking pace and the accuracy more quickly and higher, next double loop control of inverter is applied, that means current loop in internal and voltage loop in external,the double loop control framework and the adjustment relation of those parameters are given out.An LCL filter is designed and some reasonable inductance and capacitance parameters are counted, the total L is low, its resonance frequency can satisfy the stability demand of the system, the current can track the instructions rapidly, moreover, the L can reach the requirement of suppression harmonic alternating current. The major property parameters of EMI filter are insert losses, rated current, rated voltage and leak current are analysed, these who decide the EMI capability of eliminate harmonic signal and the EMI equivalent circuit about differential and common-mode are given out.35kV transformer as the principal transformer is selected, the main electric wiring and the equipment parameters are designed and analysed, it has closely connection to do with the surrounding environment, to move forward a single step, the THD and tidal current also are analysed, then the photovoltic grid brings how superiority for the electric power is compared, finally the operation theory of SVG is given and the debugging of the grid inverter and the transformer impulse test are done.