Water turbine cavitation state online evaluation method based on rapid envelope spectrum kurtosis

A technology of cavitation state and evaluation method, which is applied in processing detection response signals, using sound waves/ultrasonic waves/infrasonic waves to analyze solids, and using sound waves/ultrasonic waves/infrasonic waves for material analysis, etc. It can solve blade perforation, threats to the safe operation of units, Problems such as edge falling

Active Publication Date: 2020-04-03
STATE GRID FUJIAN ELECTRIC POWER CO LTD +2
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Problems solved by technology

When the water flows through the surface of the flow parts, cavitation will occur locally and then slight cavitation will form, which will form h

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  • Water turbine cavitation state online evaluation method based on rapid envelope spectrum kurtosis
  • Water turbine cavitation state online evaluation method based on rapid envelope spectrum kurtosis
  • Water turbine cavitation state online evaluation method based on rapid envelope spectrum kurtosis

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Embodiment Construction

[0045] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0046] Please refer to figure 1 , the present invention provides a method for online evaluation of cavitation state of hydraulic turbine based on fast envelope spectrum kurtosis, comprising the following steps:

[0047] Step S1: The ultrasonic cavitation signal measured by the broadband ultrasonic sensor installed on the water turbine; the original cavitation signal is a complex signal containing multiple frequency components, and it is almost difficult to identify the shock pulse directly using the original cavitation signal signal. image 3 It is an original cavitation sound signal, and the transient shock signal mixed in various frequency components is almost difficult to detect.

[0048] Step S2: calculate optimal band-pass filter according to fast envelope spectrum kurtosis;

[0049] Step S3: according to the original cavitation signal, adopt op...

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Abstract

The invention relates to a water turbine cavitation state online evaluation method based on rapid envelope spectrum kurtosis. The method comprises the following steps that S1, collecting original cavitation signals of a water turbine; S2, calculating an optimal band-pass filter according to the kurtosis of the fast envelope spectrum; S3, performing band-pass filtering by adopting an optimal band-pass filter to obtain an impact pulse signal waveform; S4, solving an impact pulse envelope waveform by adopting digital envelope demodulation; S5, obtaining the number of impact pulses, the time widthof each impact pulse and the amplitude of the pulse through the recognition of the envelope signal; S6, performing integral calculation on accumulated pulse impact energy in unit time and counting impact pulse density in unit time; and S7, evaluating the cavitation state of the water turbine d according to the accumulated pulse impact energy per unit time and the statistical impact pulse densityper unit time. The cavitation development degree of the rotating wheel is evaluated on line by utilizing the density and the impact energy intensity of the impact pulse.

Description

technical field [0001] The invention relates to the field of cavitation state evaluation of hydraulic turbines, in particular to an online evaluation method for cavitation state of hydraulic turbines based on fast envelope spectrum kurtosis. Background technique [0002] The hydraulic turbine is the key energy conversion unit in the hydroelectric generating set, and its working condition will directly affect the operating condition of the entire hydroelectric generating set. For hydro turbines, cavitation cavitation is an inevitable damage phenomenon. When the water flows through the surface of the flow parts, cavitation will occur locally and then slight cavitation will form, which will form honeycomb cavitation, and even develop to the perforation or edge loss of the blades, which will seriously threaten the safe operation of the unit. Cavitation is one of the main factors that lead to the decrease of turbine operating efficiency, structural damage and shortened unit life...

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Application Information

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IPC IPC(8): G01N29/46G01N29/44G01N29/04
CPCG01N29/46G01N29/4409G01N29/04G01N2291/2693
Inventor 林家洋魏运水王昕王利霞陈学仁张民威苏疆东何继全刘艺李震
Owner STATE GRID FUJIAN ELECTRIC POWER CO LTD
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