Application of Reassigned Wavelet Scalogram in Wind Turbine Planetary Gearbox Fault Diagnosis under Nonstationary Conditions

Xiaowang Chen,Zhipeng Feng

doi:10.1155/2016/6723267

Xiaowang Chen, Zhipeng Feng

Open Access

https://doi.org/10.1155/2016/6723267

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Abstract

Wind turbine planetary gearboxes often run under nonstationary conditions due to volatile wind conditions, thus resulting in nonstationary vibration signals. Time-frequency analysis gives insight into the structure of an arbitrary nonstationary signal in joint time-frequency domain, but conventional time-frequency representations suffer from either time-frequency smearing or cross-term interferences. Reassigned wavelet scalogram has merits of fine time-frequency resolution and cross-term free nature but has very limited applications in machinery fault diagnosis. In this paper, we use reassigned wavelet scalogram to extract fault feature from wind turbine planetary gearbox vibration signals. Both experimental and in situ vibration signals are used to evaluate the effectiveness of reassigned wavelet scalogram in fault diagnosis of wind turbine planetary gearbox. For experimental evaluation, the gear characteristic instantaneous frequency curves on time-frequency plane are clearly pinpointed in both local and distributed sun gear fault cases. For in situ evaluation, the periodical impulses due to planet gear fault are also clearly identified. The results verify the feasibility and effectiveness of reassigned wavelet scalogram in planetary gearbox fault diagnosis under nonstationary conditions.

Highlights

Wind turbines are playing an increasingly significant role in energy strategy
In this paper we further extend the application of reassigned wavelet scalogram to planetary gearbox fault diagnosis under nonstationary conditions [27] and validate its effectiveness in extracting gear fault features
Since gear fault usually results in sidebands around meshing frequency and its harmonics, we focus on two frequency ranges of 0–400 Hz and 0–80 Hz which cover 3/2 times stage 1 and stage 2 meshing frequencies, respectively

Summary

Introduction

Wind turbines are playing an increasingly significant role in energy strategy. harsh working conditions, for example, wind gust, dust, and unpredictable heavy load, make the power transmission system prone to fault, which may lead to catastrophic breakdown or even productivity and economic losses. Feng and Zuo [7] proposed planetary gearbox vibration signal models and deprived equations to calculate both local and distributed fault frequencies. Planetary gearbox vibration signals always feature intricate frequency component structure [15, 16], manifesting as time-varying amplitude modulation (AM) and frequency modulation (FM). In this paper we further extend the application of reassigned wavelet scalogram to planetary gearbox fault diagnosis under nonstationary conditions [27] and validate its effectiveness in extracting gear fault features.

Reassigned Wavelet Scalogram

Simulation Evaluation

Experimental Evaluations

In Situ Signal Analysis

Signal Analysis

Conclusions