Research On Modeling, Simulation And Control Algorithm Of The Receiver In A Solar Power Station

In response to the energy shortage, climate change and the pollution of the environment, many countries in the world have been actively doing research on the concentrating solar power (CSP) technologies. The solar tower power technology is one of the most economical ways to produce electricity in large scale. Because the solar energy is intermittent and the power system is nonlinear, multivariable and strong coupling, it is necessary to conduct research on the modeling and simulation of the power plant. Thus, reasonable control and heliostat field focus strategy can be designed to ensure the steady, safe and efficient operation of the plant. The receiver of the plant is an important part for photothermal conversion in the solar thermal power system. In this thesis, the models of water/steam receiver and molten salt receiver are developed and simulations are performed. The main contributions are as follows.(1) By discretizing the heat tubes axially, the sectional lumped parameter model of the water/steam receiver is established based on the Astrom-Bell model to reflect the influence of the energy distribution on the receiver system. The simulation results of the model comparing with the data of the reference and the experiment results of a real power plant as well as the dynamic characteristics of the model in different operation modes verify that the model is correct and valid.(2) As each heliostat can be manipulated independently, a pressure control method of the receiver is proposed based on the heliostat field optimal schedule. The pressure of the receiver is controlled through the solar energy concentrated on the receiver by developing and solving the optimal schedule problem based on heliostat field partition. After studying the advantages and disadvantages of using the greedy algorithm and the particle swarm optimization algorithm to solve the problem, an improved algorithm combined with those two algorithms is proposed. The simulation results demonstrate the effectiveness of the receiver control method based on the improved algorithm.(3) The sectional lumped parameter model of the molten salt receiver is established by discretizing the heat tubes axially. The model’s prototype is the Solar Two plant in the USA. The dynamic validity of the model is verified through comparison with the test document of the receiver in Solar Two plant and the transient simulation results of typical working condition. The simulation results of the tube wall temperature in different location of the receiver indicate that the model can reflect the real characteristics of the receiver. The receiver control system is simulated and the control characteristics are analyzed based on the established model.