The application of Kalman filtering to the load/pressure control of coal-fired boilers

West Burton Power Station in Nottinghamshire and Didcot Power Station in Oxfordshire both operate 4×500 MW coal-fired boilers. They are required to adjust their generated output continually in response to the demands of the National Grid. This necessitates the accurate control of the boiler stored energy and of the fuel flow to the furnace. Boiler stored energy can be inferred from such parameters as steam pressure which can be measured easily and rapidly. However, in the case of coal-fired power stations, it is very difficult to obtain an accurate dynamic measure of fuel flow and consequently to control it. A Kalman filter and optimal controller were, therefore, developed, to estimate accurately and control the fuel flow to the furnaces at West Burton Power Station. Although the furnace and the coal mills at Didcot Power Station are of different design, the work was readily transferred and used to improve the performance of an existing PI controller