Optimal Scheduling The Wind-Solar Hybrid Generation System Considering Random Variables Correlation

In order to solve the problem of environmental pollution and energy shortage, renewable energy sources are widely concerned. Wind and solar energy become the most important generation energy due to its renewability, environmentally friendly, and other features. However, unlike traditional energy, the randomness and intermittence of the wind speed and light intensity, making wind power and photovoltaic also random, non-scheduling power, which brings enormous difficulties to Scheduling the power system. Therefore, studying optimal scheduling problems of the Wind-Solar Hybrid Generation System is of great theoretical significance and application value.This paper uses Weibull distribution function and Beta distribution function to characterize the probability of wind speed and light intensity, and estimates the parameters of these distribution. Also, established the probability distribution of the power from wind turbine and PV power plant, based on the output function of the wind turbine and PV power plant. Then, the Clay-Copula function is used to characterize the joint probability distribution of wind farm and PV power plant.Since the wind and PV power are non-scheduling powers, energy storage device is added in the system to improve the efficiency of the power transmission equipment. In the optimal scheduling of Wind-Solar Hybrid Generation System, the continuity and security of power supply is a important problem. Therefore, this paper established the optimal scheduling model based on Spearman correlation coefficient, and the object of optimal scheduling is to track load curve given by the grid dispatch center in the largest degree. And the improved PSO algorithm is used to solve this optimal scheduling model.Moreover, since the randomness and uncertainty of the renewable power will reduce the reliability of the optimal scheduling. Therefore, to ensure the security, economy and flexibility of the system, an optimal scheduling model of Wind-Solar Hybrid Generation System is proposed based on Chance Constrained Programming, and Sampled Average Approximation method is used to transform the CCP to certainty problem to find the existing method for the solutions.Taking an example for a Wind-Solar Hybrid Generation System, the result shows that the Clay-Copula function distribution can better describe the JPD of the output from wind turbine and PV plant, and the proposed approach can increase the utilization ratio of photovoltaic power, improve the operating condition of the energy storage unit, and improve the ability of the wind-solar-storage hybrid generation system to track load, and make the system more environmentally friendly.