Reaserch On Credible Capacity Of Wind/PV Hybrid System

Wind power and photovoltaic power generation are widely used because of their renewability and cleanness. However, due to their intense intermittence and randomness, the access system will have a large impact on the reliability of the system. Therefore, it is necessary to study the reliability of access systems of these two kinds of renewable energy. Moreover, according to the fact that the capacity value of wind and photovoltaic power generation is often neglected in the existing power planning, which causes the waste of energy, it is of great significance to research on the credible capacity of wind power and photovoltaic power generation. Moreover, taking into account the natural complementarity of wind power and photovoltaic power generation, this paper also focus on the credible capacity and its influence factors of wind/PV hybrid system.Firstly, based on sequential Monte Carlo method, the reliability evaluation model of wind farm and photovoltaic power plant is established in this paper. As to the wind farm, wind speed is simulated through time series model, and wind farm is modeled taking into account the outage model of wind turbine and output power characteristics determined by its unit parameters. As for photovoltaic power plant, based on the solar irradiance which is calculated according to the astronomical relationship between sun and earth, slant incident solar irradiance is simulated by introducing hourly clearness index, daily and hourly temperature is modeled using time series method and the sine segmentation method respectively. The output power time series are attained according to the photovoltaic energy conversion characteristics. An example is given to verify the rationality of established model of wind farm and photovoltaic power plant. Besides, diurnal complementarity and seasonal complementarity of wind power and photovoltaic power generation is analyzed, and the feasibility of the wind/PV hybrid system is also verified by analyzing its probability distribution characteristic.Secondly, based on the established reliability model of wind power and photovoltaic power, the reliability model of the power transmission system with wind power and photovoltaic power generation is established. This chapter introduces related concepts of reliability evaluation and commonly used component reliability parameters, elaborates the basic principles and classification of Monte Carlo method, compares sequential and non-sequential Monte Carlo method, lists several reliability indexes commonly used in reliability calculation, determines the sequential states of each component and transmission lines in the system based on sequential Monte Carlo simulation algorithm, and from the system load model, derives reliability evaluation process to evaluate system reliability. By accessing the wind power and photovoltaic power generation to IEEE-RTS79 standard test system, the influence of the permeability of accessed new energy, the node position which new energy are connected to, and whether accessed wind power and photovoltaic power are complementary to system reliability indicators is analyzed.Finally, on the basis of the previous two chapters, the credible capacity of the wind/PV hybrid system accessed to system is studied. This chapter compares several commonly used definitions and principles of credible capacity, defines the credible capacity of the increased new energy using equivalent load capacity, and on the basis of this, defines the credible capacity and credibility of wind/PV hybrid system; introduces principles and methods of dichotomy and secant method commonly used to calculate credible capacity in detail, in order to solve the slow convergence problem using dichotomy and the non-convergence problem using secant method under high operating precision in the process of calculating credible capacity, develops a hybrid algorithm, which combines the merits of dichotomy and secant method, namely fast convergence and no shock phenomenon, thus shows certain advantages. By accessing wind/PV hybrid System-to RTS79 test system, programming and calculating in MATLAB, the influence of the installed capacity ratio of wind power to photovoltaic power, the permeability of accessed wind power and photovoltaic power, and the credibility of accessed system to the credible capacity and credibility of the wind/PV hybrid system is studied.