TWI Ltd Remo Demo Bristol

Copyright © TWI Ltd 2014

Jesus Jimenez

Bristol – 29th January 2015

Integrated Condition Monitoring System for Tidal Energy Generators

TWI Ltd


Presentation Outline

Introduction Design of a Tidal Device Mock-up

Techniques - Sensors

Experimental trials

Vibration vs AE results

Underwater tests (Video)

Operational demonstration (Video)

Q&A&Demo


Introduction

Maximise tidal generator availability time

Minimise life cycle maintenance costs

Condition Monitoring using

AE and Vibration Analysis

Detect faults in early stages

Low cost repaired at

scheduled maintenance works

To analyse reliability of tidal devices


Drive train mock up has been developed to validate the Condition Monitoring System

Designed to generate noise and vibration representative of a full scale tidal power system

A pair of motor and gearbox are used to represent the tidal turbine drive train both in healthy and damaged conditions.

Driving rotors to replicate operational loadings when under water.

Design of a Tidal Device Mock-up



Orders Frequency (Hz)

Shaft 1 1x 24.47 Hz

Shaft 2 0.63x 15.36 Hz

Shaft 3 0.066x 1.62 Hz

Shaft 4 0.014x 0.35 Hz

GM Stage 1 27x 660.79 Hz

GM Stage 2 6.3x 153.65 Hz

GM Stage 3 0.92x 22.64 Hz

3 stages Gearbox

3 phase motor 750W

Motor and Gearbox

Controlled by VFDs



System features

- To replicate real loadings by driving the three blades - Loads proportional to the flow speed and the rotor speed - Apertures to create misalignment if necessary


Acoustic Emissions are defined as transient elastic waves generated from rapid release of strain energy caused by deformation or damage within or on the surface of the material.

Monitoring Techniques

Acoustic Emission (AE) Vibration Analysis (VA)

Relates to the motion of a body regarding a reference point (centre line of a shaft). It is a result of an excitation force and may be random or periodic.


Sensors

Vibration Sensors - Accelerometers Acoustic Emission Sensors

Performance tested underwater


Establish a correlation between AE and Vibration signals with the condition of the gearbox deteriorating

Experimental Trials

Case 1: Healthy Motor

Case 2: Lubricant Removal– Oil starvation

Case 3: Addition of 4g Iron Oxide Particles– Debris

Case 4: Addition of 12g Iron Oxide Particles – Debris

Case 5: Induced Gear Teeth Defect – Macro-pitting

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Experimental Trials

Case 1: Healthy Motor

Case 2: Lubricant Removal - Oil starvation

• Rotational Frequency: 50 Hz. • Healthy motor without any kind of defect.

• Rotational Frequency: 50 Hz.

• Remove the oil from the gearbox. • Run the motor for 15 min prior to acquiring data. • Start acquiring AE and Vibration data.


Experimental Trials

Case 3: Addition of 4g Iron Oxide Particles - Debris

Case 4: Addition of 12g Iron Oxide Particles - Debris

• Rotational Frequency: 50 Hz

• Refill the gearbox with clean oil.

• Introduced debris gradually in the area where the gears mesh.

• It was done with the motor running at very low speed to spread them homogeneously.

• Iron Oxide particles as debris


Experimental Trials

Case 5: Induced Gear Teeth Defect – Macro-pitting

The seeded defect was

introduced on the tooth

Development of higher damage

levels (still low) creating

macro-pitting scuffing


AE Results

- Low amplitude due to attenuation from bearings and gears to the case and lubrication - Continuous noise - No discreet AE events

Healthy condition AE signal

Faulty condition AE signal

FFT of filtered AE Signal

- Waveform acquired with high amount of debris - Discrete AE event generated by abrasion of the particles

- Activity 30 – 160kHz

AE event


Vibration Results

Fast Fourier Transform

1x Trending

- High speed shaft frequency (1x)

- Second Harmonic of the main frequency (2x)

- Changes occurring in the 1x peak level as the level of damage in the gearbox is higher - Increase in the peak amplitude - More sensitivity in the last two scenarios

1x

2x


AE – Better Quantitative Results

Vibration – Better Qualitative Results

Comparison AE - Vibration

Damage Level

Vibration Progress AE Progress


Underwater Tests


Operation Video


Conclusions and next steps

The REMO technology has proved its capabilities to detect machinery faults at early stage which can lead to financial benefits for O&M operations in Tidal Energy Devices.

Further failure mechanisms specific to Tidal Energy systems can be under control using parallel technology solutions developed by TWI.

Feedback, awareness and guidance from industry developers will help to increase the TRL for commercialisation.


Q&A&D

Jesus Jimenez

TWI Ltd

[email protected]

19

TWI Ltd Remo Demo Bristol

Engineering

Transcript of TWI Ltd Remo Demo Bristol