Research On Application Of System Identification Theory To Vibration Of Hydropowergenerator Unit And Supporting Structure

Compared with that of middle and small-scale hydropower station, vibration ofhydropowergenerator unit and it's supporting structure of large-scale hydropowerstation is more acute for it's unit capability and structure form. So many problemsfollowing the frequent and large vibration do influence safe and economical operationof hydropower station. So it is an important and significant task to study vibration ofhydropowergenerator unit and it's supporting structure to research law and characterof vibration.Based on the original data of in-situ test on Lijiaxia hydropower station, thispaper, from the view of system theory, deals with vibration signal ofhydropowergenerator unit as input signal of system composed withhydropowergenerator unit and it's supporting structure on one hand and vibrationsignal of the supporting structure as output signal of the system on the other hand.Consequently, the SISO and MISO state-space equations characterising dynamicalvibration of the system are obtained as results of applying system identification theoryto the concerning signals, and are used to analyse vibration of the system and topredict output signals。The results show that the system identification models reflectdynamical character of the system properly and some valuable conclusion and goodpredictions can be obtained through this method.It can be concluded from this paper that system identification theory, as a sharptool for analyzing "gray box" problem, is suitable to be used to construct dynamicalmodel of vibration of hydropower station for analyzing character of the system andpredicting output signal. So the method and conclusions that this paper contains canfind their ways into practical project and research fields and is worthy of beingstudied and popularized deeply.