Vibration modal identification method of high voltage isolating switch based on orthogonal polynomia

Abstract

As the most widely used high voltage equipment in power system, the fault monitoring, analysis, prevention, elimination to ensure its safe and reliable operation, have been widely concerned in recent years. In this paper, the high voltage isolation switch type of GW4D-126(G•W) is concerned. Firstly, various modal parameter identification methods in time and frequency domain are studied. The modal parameter identification in frequency domain by complex orthogonal polynomial curve fitting method is analyzed. Secondly, an algorithm for modal parameter identification by orthogonal polynomial method is proposed. Its accuracy and feasibility are verified by MATLAB. Thirdly, the data analysis methods such as signal preprocessing (eliminating trend term, smoothing curve) and filtering are presented. The experimental modal parameters are identified based on orthogonal polynomial method. Then the modal parameters such as natural frequency, damping ratio and vibration shape are obtained. Finally, the test results are compared with the finite element simulation, so as to verify that the vibration analysis method can be applied to the disconnector status diagnosis.