Application Of Model Predictive Control In Power Plant Superheated Steam Temperature Control

Power plant superheated steam temperature is time-variant and always influenced by kinds of disturbance. Attempering water is used to regulate it. But transfer delay exists from attempering water to superheated steam temperature. Casecade PID control system is generally used to control superheated steam temperature, but it belongs to feedback control, a kind of lagging control, its control effect is not very good for the controlled plant which have transfer delay, especially which is influenced by strong disturbance, and it does not have adaptive ability. The operator makes set point of superheated steam temperature lower to prevent overheating, but it reduces the cycle efficiency. By studying superheated steam temperature's characteristic, application of Model Predictive Control(MPC) in superheated steam temperature control can improve control quality and raise control accuracy, so the set point of superheated steam temperature could be raised in operation to increase the cycle efficiency for more economic benefit. To verify the effect of MPC, experimental data from a power plant was used to recognize mathematical model of the controlled plant, and Model Predictive Controller was designed and then used to do the application of Model Predictive Controller in superheated steam temperature control simulation experiment. Result indicates that MPC can enormously improve dynamic characteristics and anti-interference capability of the system, it effectively promote superheated steam temperature control quality.