Transient Hydraulic Pressure Fluctuation Analysis of a Hydroturbine via Ensemble Empirical Mode Decomposition

DOI

10.2991/emeit.2012.389How to use a DOI?

Keywords

Hilbert-Huang Transform, Ensemble Empirical Mode Decomposition, Time-frequency Analysis, Nonstationary Signal, Hydroturbine, Transient Process, Pressure Fluctuation, Draft Tube

Abstract

Hydroturbines are the key asset in hydroelectric power stations, and their monitoring and diagnosis play an important role in the asset management and maintenance. Hydraulic pressure fluctuation is inevitable during the operation of hydroturbines. It has nonstationarity during transient processes. The hydraulic pressure fluctuation signal measured in the draft tube of an axial-flow hydroturbine during a start-up transient process is analyzed based on ensemble empirical mode decomposition and Hilbert spectrum. The frequency components and their time evolution with the operating conditions are identified. A dominant low frequency component waxing and waning around a constant smaller than the rated rotating frequency exists throughout the transient process, indicating the possible occurrence of vortex core. Both the amplitude and the frequency are time varying, and are closely related to the operating conditions, especially the guide vane opening and switch, but they are not dominated by the speed. The closure and opening of guide vane and the on-off switching of hydroturbine can result in large amplitude pressure fluctuation, even the pressure surges or impulses in draft tube, which may excite the resonance of some parts and destroy the operating stability. The Hilbert spectrum based on ensemble empirical mode decomposition is suitable to analyze the nonstationary hydraulic pressure fluctuation signals of low frequency.

Copyright

© 2012, the Authors. Published by Atlantis Press.

Open Access

This is an open access article distributed under the CC BY-NC license (http://creativecommons.org/licenses/by-nc/4.0/).

Download article (PDF)

TY  - CONF
AU  - Canxun Du
AU  - Weihua Gui
AU  - Zhikun Hu
PY  - 2012/09
DA  - 2012/09
TI  - Transient Hydraulic Pressure Fluctuation Analysis of a Hydroturbine via Ensemble Empirical Mode Decomposition
BT  - Proceedings of the 2nd International Conference on Electronic & Mechanical Engineering and Information Technology (EMEIT 2012)
PB  - Atlantis Press
SP  - 1755
EP  - 1760
SN  - 1951-6851
UR  - https://doi.org/10.2991/emeit.2012.389
DO  - 10.2991/emeit.2012.389
ID  - Du2012/09
ER  -