Combined expert system/neural networks method for process fault diagnosis
First Claim
1. A method for diagnosing failures in the operation of a thermal-hydraulic system including detection of a malfunctioning component in said thermal-hydraulic system, said method comprising the steps of:
- classifying a malfunction of the component by a function performed by the component as a mass source/sink, or a momentum source/sink, or an energy source/sink imbalance including the steps of;
assigning to one or more of the components of the thermal-hydraulic system a thermal-hydraulic control volume which characterizes the total mass, momentum, and energy inventories of said one or more components during normal and off-normal operations;
assigning to each thermal-hydraulic control volume its associated mass, momentum, and energy conservation equations;
assigning to one or more components a functional classification as a source or sink of mass, momentum, or energy;
assigning components to generic component classes by said functional classification;
monitoring operation of the thermal-hydraulic control volumes for detecting an imbalance in the total mass, momentum, or energy inventories in any of the thermal-hydraulic control volumes; and
comparing a detected imbalance in mass, momentum, or energy inventories of the thermal-hydraulic control volumes with the conservation equations and the functional classification for each of the components and identifying a given component as faulty when a detected imbalance in mass, momentum, or energy of the thermal-hydraulic control volume matches the classification of the component as a source or sink of mass, momentum, or energy;
classifying the function as one of a plurality of generic component classes for each of said mass, momentum and energy source/sink imbalances; and
classifying a specific component within one of said generic component classes as said malfunctioning component.
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Abstract
A two-level hierarchical approach for process fault diagnosis is an operating system employs a function-oriented approach at a first level and a component characteristic-oriented approach at a second level, where the decision-making procedure is structured in order of decreasing intelligence with increasing precision. At the first level, the diagnostic method is general and has knowledge of the overall process including a wide variety of plant transients and the functional behavior of the process components. An expert system classifies malfunctions by function to narrow the diagnostic focus to a particular set of possible faulty components that could be responsible for the detected functional misbehavior of the operating system. At the second level, the diagnostic method limits its scope to component malfunctions, using more detailed knowledge of component characteristics. Trained artificial neural networks are used to further narrow the diagnosis and to uniquely identify the faulty component by classifying the abnormal condition data as a failure of one of the hypothesized components through component characteristics. Once an anomaly is detected, the hierarchical structure is used to successively narrow the diagnostic focus from a function misbehavior, i.e., a function oriented approach, until the fault can be determined, i.e., a component characteristic-oriented approach.
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Citations
14 Claims
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1. A method for diagnosing failures in the operation of a thermal-hydraulic system including detection of a malfunctioning component in said thermal-hydraulic system, said method comprising the steps of:
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classifying a malfunction of the component by a function performed by the component as a mass source/sink, or a momentum source/sink, or an energy source/sink imbalance including the steps of; assigning to one or more of the components of the thermal-hydraulic system a thermal-hydraulic control volume which characterizes the total mass, momentum, and energy inventories of said one or more components during normal and off-normal operations; assigning to each thermal-hydraulic control volume its associated mass, momentum, and energy conservation equations; assigning to one or more components a functional classification as a source or sink of mass, momentum, or energy; assigning components to generic component classes by said functional classification; monitoring operation of the thermal-hydraulic control volumes for detecting an imbalance in the total mass, momentum, or energy inventories in any of the thermal-hydraulic control volumes; and comparing a detected imbalance in mass, momentum, or energy inventories of the thermal-hydraulic control volumes with the conservation equations and the functional classification for each of the components and identifying a given component as faulty when a detected imbalance in mass, momentum, or energy of the thermal-hydraulic control volume matches the classification of the component as a source or sink of mass, momentum, or energy; classifying the function as one of a plurality of generic component classes for each of said mass, momentum and energy source/sink imbalances; and classifying a specific component within one of said generic component classes as said malfunctioning component. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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Specification