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Shock and Vibration
Volume 2018, Article ID 5382398, 14 pages
https://doi.org/10.1155/2018/5382398
Research Article

A SVDD and -Means Based Early Warning Method for Dual-Rotor Equipment under Time-Varying Operating Conditions

College of Mechanical and Electrical Engineering, Beijing University of Chemical Technology, Beijing, China

Correspondence should be addressed to Kun Feng; moc.361@dhpgnefnuk

Received 15 August 2017; Revised 4 December 2017; Accepted 12 December 2017; Published 4 January 2018

Academic Editor: Sandris Ručevskis

Copyright © 2018 Zhinong Jiang et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Under frequently time-varying operating conditions, equipment with dual rotors like gas turbines is influenced by two rotors with different rotating speeds. Alarm methods of fixed threshold are unable to consider the influences of time-varying operating conditions. Hence, those methods are not suitable for monitoring dual-rotor equipment. An early warning method for dual-rotor equipment under time-varying operating conditions is proposed in this paper. The influences of time-varying rotating speeds of dual rotors on alarm thresholds have been considered. Firstly, the operating conditions are divided into several limited intervals according to rotating speeds of dual rotors. Secondly, the train data within each interval is processed by SVDD and the allowable ranges (i.e., the alarm threshold) of the vibration are determined. The alarm threshold of each interval of operating conditions is obtained. The alarm threshold can be expressed as a sphere, whose controlling parameters are the coordinate of the center and the radius. Then, the cluster center of the test data, whose alarm state is to be judged, can be extracted through -means. Finally, the alarm state can be obtained by comparing the cluster center with the corresponding sphere. Experiments are conducted to validate the proposed method.