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Transcript of Vibroacoustic Transformer Condition Monitoring · PDF fileVibroacoustic Transformer Condition...

  • Faculty of Health, Engineering & Sciences

    Vibroacoustic Transformer Condition Monitoring

    A dissertation submitted by

    Dean Mark Starkey

    Student ID: 0061038897

    in fulfilment of the requirement of

    ENG4112 Research Project Part 2

    towards the degree of

    Bachelor of Engineering (Honours)

    Major Power Engineering

    October 2016

  • Dean Starkey | 0061038897 i

    ABSTRACT

    Throughout the life of a transformer the effects of mechanical shocks, insulation

    aging, thermal processes and short circuit forces will cause deformations in the

    winding. This deformation can lead to vibration in the transformer and mechanical

    fatigue of the solid insulation. Defects which form in a transformers structure can

    cause faults such as partial discharge, hot spots and arcing. These faults generate

    combustible gases which can be analysed for condition assessment of the transformer.

    The development of a suitable and cost effective vibration measurement system forms

    a key part of this research project. A monitoring system is developed for real-time

    vibration analysis. An embedded capacitive accelerometer is used in conjunction with

    an Arduino microcontroller to record vibrations. The sensor platform is designed to

    communicate wirelessly via XBee radios to a terminal computer. A software program

    and user interface is designed as a tool for analysis.

    The outcomes and benefits of these works are primarily based on determining the

    condition of transformer insulation through measurements of vibration. Following a

    working measurement system, suitable transformer sites are monitored. Spectral

    analysis is performed in the frequency domain to determine a correlation with gas

    analysis results. The validity of vibroacoustic measurement as a predictive

    maintenance tool is subsequently evaluated.

    Six transformers are chosen for vibration monitoring with analysis of the vibration

    signatures correlated to the dissolved gas analysis reports at each site. The vibration

    signatures at each location are analysed using the Short Time Fourier Transform and

    frequency peaks compared for the different sites. It was noted that sensor location does

    not have a large impact on vibration magnitudes and identifying the frequency

    components present in the signal. However, from the signatures obtained there is not

    enough variation in magnitude or frequency components to suggest that this method

    can identify the type of fault present.

  • Dean Starkey | 0061038897 ii

    LIMITATIONS OF USE

    The Council of the University of Southern Queensland, its Faculty of Health,

    Engineering & Sciences, and the staff of the University of Southern Queensland, do

    not accept any responsibility for the truth, accuracy or completeness of material

    contained within or associated with this dissertation.

    Persons using all or any part of this material do so at their own risk, and not at the risk

    of the Council of the University of Southern Queensland, its Faculty of Health,

    Engineering & Sciences or the staff of the University of Southern Queensland.

    This dissertation reports an educational exercise and has no purpose or validity beyond

    this exercise. The sole purpose of the course pair entitled “Research Project” is to

    contribute to the overall education within the student’s chosen degree program. This

    document, the associated hardware, software, drawings, and other material set out in

    the associated appendices should not be used for any other purpose: if they are so used,

    it is entirely at the risk of the user.

  • Dean Starkey | 0061038897 iii

    CERTIFICATION

    I certify that the ideas, designs and experimental work, results, analyses and

    conclusions set out in this dissertation are entirely my own effort, except where

    otherwise indicated and acknowledged.

    I further certify that the work is original and has not been previously submitted for

    assessment in any other course or institution, except where specifically stated.

    Dean Starkey

    Student Number 0061038897

    Signature

    Date

  • Dean Starkey | 0061038897 iv

    ACKNOWLEDGEMENTS

    I would like to thank my supervisors Mr Andreas Helwig and Dr Narottam Das for

    their guidance, feedback and support during this project.

    I would also like to thank my work colleague Matthew Gibson for providing the DGA

    information and reports needed. I would like to thank my parents for their continued

    support and encouragement throughout this journey. Above all I would like to thank

    my wife Yasmin Starkey for patiently supporting me in my studies over the past five

    years.

  • Dean Starkey | 0061038897 v

    ABSTRACT ................................................................................................................. i

    LIMITATIONS OF USE ........................................................................................... ii

    CERTIFICATION .................................................................................................... iii

    ACKNOWLEDGEMENTS ...................................................................................... iv

    LIST OF FIGURES .................................................................................................. ix

    LIST OF TABLES .................................................................................................. xiii

    ............................................................................................................. 15

    INTRODUCTION .................................................................................................... 15

    1.1 Project Aim ................................................................................................ 16

    1.2 Project Objectives ...................................................................................... 17

    1.3 Ethical Considerations ............................................................................... 18

    ............................................................................................................. 20

    BACKGROUND AND LITERATURE ................................................................. 20

    2.1 Magnetostriction ........................................................................................ 20

    2.2 Acoustic Signals ......................................................................................... 22

    2.3 Traditional Condition Monitoring .............................................................. 23

    Chemical Detection ................................................................................ 24

    Acoustic Detection ................................................................................. 26

    Source location of partial discharge ....................................................... 26

    2.4 Vibroacoustic Condition Monitoring ......................................................... 28

    2.5 Signal Processing ....................................................................................... 29

  • Dean Starkey | 0061038897 vi

    Shannon Nyquist Sampling Theorem .................................................... 29

    Fast Fourier Transform (FFT) ................................................................ 30

    Window Function ................................................................................... 30

    Power Spectral Density (PSD) ............................................................... 31

    2.6 Review of Information ............................................................................... 32

    ............................................................................................................. 33

    METHODOLOGY ................................................................................................... 33

    3.1 Measurement System Hardware ................................................................ 33

    Sensor Selection ..................................................................................... 34

    Microcontroller ...................................................................................... 38

    Resource Analysis .................................................................................. 40

    3.2 Measurement System Software .................................................................. 42

    3.3 Controlled Experiment ............................................................................... 44

    3.4 Field Testing .............................................................................................. 46

    Condition Analysis ................................................................................. 46

    Site Selection .......................................................................................... 47

    3.5 Risk Assessment ........................................................................................ 50

    .....................................................................