FUZZY METHOD FOR CONTROLLING WATER LEVEL OF STEAM DRUM

摘要

PURPOSE:To improve an operation control performance by a method wherein the amount of adjustment of the opening of a feed water adjusting valve is inferred discretely by a three kinds of fuzzy inference elements on the basis of a steam drum water level deviation, a water level change rate, etc. and a weighting synthetic computation is executed therefor in accordance with the state of a plant. CONSTITUTION:Receiving a steam drum water level deviation etc. as inputs, a first fuzzy inference element 51 of a steam drum system infers the amount of operation of a valve according to such a control rule that 'the valve is closed in a large degree when a level difference is positive and large and when a level change rate is large', for instance. When a flow rate evaluated from the opening of a main valve etc. is inputted, a second fuzzy inference element 52 of a steam-feed water flow rate system infers the amount of operation of the valve according to such a control rule that 'the valve is closed when the flow rate deviation shows that feed water is somewhat excessive', for instance. Receiving as an input a flow rate deviation of an actual feed water flow rate from an optimum feed water flow rate, which is evaluated from a reactor output, a third fuzzy inference element 53 of a reactor output system infers the amount of operation of the valve according to such a control rule that 'the valve is closed in a large degree when the flow rate deviation shows that the feed water is excessive', for instance. Such three discrete inferences as statd above are executed, a weighting synthetic computation is executed and thereby the opening of a feed water adjusting valve is controlled.