Study On Leakage Fault Of Hydraulic Inlet Guide Vane System Of Heavy Gas Turbine Compressor

The Inlet Guide Vane(IGV)system of heavy gas turbine compressor plays an important role in ensuring the safe operation of the unit and improving operating efficiency.The IGV system of the mainstream gas turbine compressor adopts the electro-hydraulic servo control mode.For the IGV system of compressors,the leakage in the hydraulic cylinder can be a cause of operating efficiency decline,and even lead to unit trip accidents.This paper is aimed to find a more efficient solution for fault diagnosis of internal leakage of in IGV system of gas turbine compressors.Previous studies on internal leakage faults are mostly based on universal hydraulic systems.However,the IGV system of heavy gas turbine compressor operates under changing load conditions.The diagnostic efficiency of the existing methods for internal leakage is still unclear.In view of the internal leakage of IGV systems under variable load conditions,taking the characteristics of position movement and load variation,this paper presented a new diagnostic method based on EEMD combined with Hilbert transform.In addition,a simulation experiment platform for internal leakage of IGV systems was built,and experiments were carried out to verify the efficiency of the proposed diagnosis method.To diagnose the internal leakage fault in hydraulic cylinder of IGV system,the hydraulic pressure signal is decomposed into a series of Intrinsic Mode Function(IMF)components by EEMD.Then the HT transform is used to transform the first few IMF components to obtain the instantaneous amplitude.Finally,combined with the time-domain eigenvalues,the fault feature extraction and the diagnosis of internal leakage are carried out.In this paper,according to the working principle of IGV system and the form of internal leakage fault,hydraulic circuit design and reconstructions of the existing experimental platform are carried out.And based on the LabVIEW software,experimental bench control program and data acquisition program were completed.Through the above work about IGV system leakage simulation platform,the hardware and software for experimental research were prepared.The experiment results verified that the EEMD-based method can effectively diagnose the occurrence and degree of hydraulic cylinder leakage in IGV system.Then,based on the comparative analysis of EEMD,EMD and wavelet packet theory,the effectiveness of three methods for diagnosis of internal leakage was compared by experiments.The comparison results show that,for different levels of internal leakage,EEMD is more sensitive to fault features and has better diagnostic performance.