Monitoring and vibrational diagnostic of rotating machinery in power plants

Due to safety and economical reasons diagnostic and monitoring systems are of growing interest in all complex industrial production lines. Key components of power plants are rotating machinery like mills, blowers, feedwater pumps and turbines. Diagnostic systems are requested which detect, diagnose and localize faulty operation conditions at an early stage in order to prevent severe failures. The knowledge of the vibrational machine signatures and their time dependent behavior are the basis of efficient condition monitoring. By only the use of vibration thresholds given by norms and standards, alarms often occur without giving hints to the source of excitation. Therefore, modern measurement techniques in combination with advanced computerized data processing and acquisition show new ways in the field of machine surveillance by use of spectral- and correlation analysis of acceleration, displacement and the operational process-parameters (e.g. temperature, pressure, steam flow, etc.). Time domain analysis using characteristic values to determine changes by trend setting, spectrum analysis to determine trends of frequencies, amplitude and phase relations, correlation analysis to evaluate common sources of excitation by comparing different sensor signals, as well as cepstrum analysis to detect periodical components of spectra are used as evaluation tools.