Evaluation of plant alarm systems by behavior simulation using a virtual subject

To design an effective plant alarm system, it is essential to evaluate various performances of fault detection and identification (FDI) in emergencies. In this study, an operator model, which mimics the FDI behavior of a human operator with primary cognitive and executive capabilities, is developed as a virtual subject for supervising a chemical plant system. Analyzing the FDI tracks generated by the behavior simulation using the virtual subject under an alarm system makes it possible to evaluate the performance of the alarm system. In a case study, the evaluation method using the virtual subject is applied for designing an appropriate alarm system in a boiler-plant simulator. FDI performances of the original alarm system for all assumed malfunctions are evaluated and alarm signal selection and limit settings are reconsidered according to the evaluation results. The results of the case study demonstrate the usefulness of the model-based evaluation method.