Multi-Variant Modal Analysis Approach for Large Industrial Machine

Abstract

Power generation technologies are essential for modern economies. Modal Analysis (MA) is advanced but well-established method for monitoring of structural integrity of critical assets, including power ones. Apart from classical MA, the Operational Modal Analysis approach is widely used in the study of dynamic properties of technical objects. The principal reasons are its advantages over the classical approach, such as the lack of necessity to apply the excitation force to the object and isolate it from other excitation sources. However, for industrial facilities, the operational excitation rarely takes the form of white noise. Especially in the case of rotating machines, the presence of rotational speed harmonics in the response signals causes problems with the correct identification of the modal model. The article presents a hybrid approach where combination of results of two Operational Modal Analyses and Experimental Modal Analysis is performed to improve the models’ quality. The proposed approach was tested on data obtained from a 215 MW turbogenerator operating in one of Polish power plants. With the proposed approach it was possible to diagnose the machine’s excessive vibration level correctly.

Analysis of Dual-Driven Feed System Vibration Characteristics Based on Computer Numerical Control Machine Tools: A Systematic Review

“…So far, the research has confirmed two standard methods for extracting modal parameters, including operational modal analysis (OMA) as well as experimental modal analysis (EMA) [71,72]. When comparing the two methods, each has benefits and drawbacks.…”

Vibration Signal Evaluation Based on K-Means Clustering as a Pre-Stage of Operational Modal Analysis for Structural Health Monitoring of Rotating Machines

“…More recent studies carried out by [5] showed that even the turbulent gas flow within the seals of a turbomachine can be used to excite the system and identify the modal parameters via OMA, demonstrating OMA's potential for condition monitoring. Moreover, in [6] it was verified that a hybrid approach based on both OMA and EMA was able to diagnose a vibration problem in a large rotating machine used in the power generation industry. It is important to highlight that OMA was used to identify that a resonance frequency was causing the problem.…”