Natural frequency estimation by using torsional response, and applications for wind turbine drivetrain fault diagnosis

Farid K Moghadam,Amir R Nejad

doi:10.1088/1742-6596/1618/2/022019

Abstract

A method based on torsional vibration measurements for a system-level condition monitoring of the drivetrain system is developed in this paper. The latter is tested by using a 10MW wind turbine drivetrain simulation model, and experimentally validated by the drivetrain operational data obtained from a 1.75MW turbine. The method relies on the estimation of the drivetrain torsional natural frequencies by using the torsional responses residual function and subsequent monitoring of the variations in the eigenfrequencies and normal modes. In other words, an abnormal deviation from the reference values of these dynamic parameters can be translated into a meaningful interpretation on the propagation of a specific fault in the driveline. Local sensitivity analysis is employed to establish a relationship between different types of drivetrain faults and the system dynamic properties.

Highlights

Multi-megawatt offshore wind turbines are considered as a solution for the large-scale realization of renewable power generations
A method based on torsional vibration measurements for a system-level condition monitoring of the drivetrain system is developed in this paper
The method relies on the estimation of the drivetrain torsional natural frequencies by using the torsional responses residual function and subsequent monitoring of the variations in the eigenfrequencies and normal modes

Summary

Introduction

Multi-megawatt offshore wind turbines are considered as a solution for the large-scale realization of renewable power generations. Offshore wind industry still suffers from longer downtime, high cost for repair and replacement of this system and higher risk of loss of turbine. The latter is due to the larger components and the difficulty to access the system in offshore environments, and a wider range of excitations due to the synergistic impacts of waves, currents and wind turbulences which call for innovative approaches to have a better understanding about the system dynamics and excitations. The focus of this research is proposing a system-level drivetrain condition monitoring (CM) solution by estimation and monitoring of the system dynamic properties The latter is performed by developing a numerical model of the drivetrain as a dynamic system based on its measured torsional response and the subsequent estimation of torsional frequencies. The motivation is to reduce operational expenditure (OPEX) and subsequently levelized cost of energy (LCOE) to make offshore wind power competitive with land-based wind turbines

Methods

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Conclusion