An expert system-based, on-line rotor crack monitor for utility steam turbines

A steam turbine vibration monitoring system is described that uses a rule-based expert system for data review and fault diagnosis. Steady-state, coast-down, and steam temperature transient vibration signature techniques used by the monitor to detect transverse rotor cracks are summarized. A histogram technique for enhancing the initial appearance of shallow crack 2/rev response is presented. The use of an expert system to fully automate diagnosis of turbine faults is discussed. Rotor crack and misalignment diagnostic rules are outlined.