Research On Capacity Credit Of Large-scale Kenewable Energy Sources

The shortage of the conventional energy and the environmental problems caused during the application process make people pay attention to the wind energy and the solar energy. The wind power and photovoltaic power generation can provide certain amount of credible capacity just as the conventional ones do, which will contribute to the reliability of the power system. But the stochastic nature and the volatility of the two new energies will exert negative influences on the steady operation of the system with the large-scale new energy on-grid, which badly needs the research for the reliability and the capacity credit for the new energies.The power generation models of the wind farms and the photovoltaic plant are constructed. The wind velocity for the wind farms are simulated by means of Weibull distribution method combined with the wake effect model. And the Beta distribution is applied in the simulation of the light intensity. With the models and simulation results above, the calculation method of the output power of the wind farms and the photovoltaic plant per hour is obtained. The application scopes of the sequential and non-sequential Monte-Carlo simulation methods are compared based on the principle of the Monte-Carlo simulation. Then based on the sequential Monte-Carlo simulation, the reliability assessment models for the power generation and transmission system including the new energy are constructed. The Matlab is utilized to calculate the reliability indexes for the IEEE-RTS79test system. The different influences on the reliability of the system caused by different access capacities and access points are compared, and the reliability differences caused by the access modes namely, simultaneously and separately, are all compared. Based on the two parts of content above, the capacity credit for the new energy is studied. The definition and calculation method of the capacity credit for the new energy are proposed based on the effective load carrying capacity. The secant method combined with the Monte-Carlo simulation is applied in assessment of the capacity credit for the wind farms and the photovoltaic plant in the IEEE-RTS79, and the results are analyzed.Through the case study, the influences on the reliability of the system exerted by the wind farms and the photovoltaic plants are assessed, and the capacity values are calculated, which will serve as the reference for the new energy planning.