Method for determining operation state of hydraulic turbine based on EMD theory and HHT transformation

Abstract

The present invention proposes a method for determining the operation state of a hydraulic turbine based on an EMD theory and HHT transformation. The method comprises the following steps: Step 1, collecting a pressure fluctuation signal by using a pressure sensor; Step 2, performing downsampling processing on the pressure fluctuation signal; Step 3, using the wavelet transformation to de-noise thepressure fluctuation signal after being subjected to downsampling to obtain a pressure fluctuation reconstructed signal; Step 4, adding a high-frequency sine signal with known frequency to the pressure fluctuation reconstructed signal, and determining the new boundary of the pressure fluctuation reconstructed signal by using the image continuation method; Step 5, using the EMD decomposition method to decompose the pressure fluctuation reconstructed signal to obtain each IMF component; Step 6, performing the Hilbert transformation one by one on each IMF component obtained by the EMD decomposition to obtain an instantaneous energy spectrum of the pressure fluctuation reconstructed signal; and Step 7, according to the instantaneous energy spectrum, determining the operation state of the hydraulic turbine. The method provided by the present invention has important significance for analyzing the fault state of the operation of the hydraulic turbine.

Description

technical field [0001] The invention relates to the running stability of a water turbine, in particular to a method for judging the running state of a water turbine based on EMD theory and HHT transformation. Background technique [0002] Since the 1970s, many large-scale hydropower installations at home and abroad have experienced many large-scale accidents caused by unit vibration. Hydraulic experts have done a lot of numerical simulation and experimental research in the field of research on the stability of hydraulic turbines. Theoretical research mainly includes direct numerical simulation method, large eddy simulation method, inviscid flow numerical simulation method, and Reynolds averaging method. In recent years, with the rapid development of computational fluid dynamics, the time-averaged Navier-Stokes equation is used as the theoretical basis, the k-ε turbulence model is adopted, and the incompressible single-phase flow is considered, it is divided into Viscosity, ...

AI Technical Summary

Problems solved by technology

At the current stage, it has not been possible to improve the efficiency of hydroelectric power generation to the maximum and at the same time ensure the stability of operation 100%. The characteristics of the pressure pulsation signal under various working conditions, to achieve remote real-time monitoring of the operation of the turbine

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