Condition monitoring of rotating electrical machines

Cover
Contents
About the authors
Preface
Acknowledgements
Nomenclature
Abbreviations
1 Introduction to condition monitoring
	1.1 Introduction
	1.2 Need for monitoring
	1.3 What and when to monitor
	1.4 Technological timelines
	1.5 Structure of text and bibliographies
2 Rotating electrical machines
	2.1 Introduction
	2.2 Electrical machines structures and types
	2.3 DC machines
	2.4 AC machines, synchronous
	2.5 AC machines, asynchronous or induction
	2.6 Permanent magnet or reluctance machines
	2.7 Other machine types
		2.7.1 Multi-phase machines
		2.7.2 Doubly fed and variable-speed drive machines
	2.8 Conclusions
3 Electrical machine construction, operation and failure modes
	3.1 Introduction
	3.2 Materials, strength and temperature
	3.3 Electrical machine construction
		3.3.1 General
		3.3.2 Stator core and frame
		3.3.3 Stator windings
		3.3.4 Rotors and windings
		3.3.5 Enclosures
		3.3.6 Connections and heat exchangers
		3.3.7 Summary
	3.4 Machine specification and failure modes
	3.5 Insulation ageing mechanisms
		3.5.1 General
		3.5.2 Thermal ageing
		3.5.3 Electrical ageing
			3.5.3.1 General
			3.5.3.2 Partial discharges
			3.5.3.3 Surface tracking and moisture absorption
			3.5.3.4 Transient voltages
		3.5.4 Mechanical ageing
		3.5.5 Environmental ageing
		3.5.6 Synergism between ageing stresses
	3.6 Insulation failure modes
		3.6.1 General
		3.6.2 Stator winding insulation
			3.6.2.1 General
			3.6.2.2 Delamination and voids
			3.6.2.3 Slot discharge
			3.6.2.4 Stator end windings
			3.6.2.5 End-winding stress grading
			3.6.2.6 Repetitive transients
		3.6.3 Stator winding faults
			3.6.3.1 Winding faults (All machines)
			3.6.3.2 Winding conductor faults (Generators)
			3.6.3.3 Winding inter-turn faults (All machines)
			3.6.3.4 End winding faults (All machines)
			3.6.3.5 Winding coolant system faults (Large machines)
		3.6.4 Rotor winding faults
			3.6.4.1 General
			3.6.4.2 Winding faults (Induction motors)
			3.6.4.3 Winding faults (Turbo-generators)
			3.6.4.4 Winding faults (DC machines)
	3.7 Other failure modes
		3.7.1 Stator core faults (Turbo-and hydro-generators)
		3.7.2 Connection faults (HV motors and generators)
		3.7.3 Water coolant faults (All machines)
		3.7.4 Bearing faults (All machines)
		3.7.5 Shaft voltages (Large machines)
	3.8 Conclusions
4 Reliability of machines and typical failure rates
	4.1 Introduction and business of failure
	4.2 Definition of terms
	4.3 Root cause and FMEA
		4.3.1 General
		4.3.2 Typical root causes and failure modes
		4.3.3 Root causes
		4.3.4 Failure modes
	4.4 Reliability analysis
	4.5 Machine structure
	4.6 Typical failure rates and MTBFs
	4.7 Conclusions
5 Signal processing and instrumentation requirements
	5.1 Introduction
	5.2 Spectral analysis
	5.3 Higher-order spectral analysis
	5.4 Correlation analysis
	5.5 Vibration signal processing
		5.5.1 General
		5.5.2 Cepstrum analysis
		5.5.3 Time averaging and trend analysis
	5.6 Wavelet analysis
	5.7 Model-based information extraction
		5.7.1 Kalman filter
		5.7.2 Observer
	5.8 Temperature instrumentation
	5.9 Vibration instrumentation
		5.9.1 General
		5.9.2 Displacement transducers
		5.9.3 Velocity transducers
		5.9.4 Accelerometers
	5.10 Force and torque instrumentation
	5.11 Electromagnetic instrumentation
	5.12 Wear and debris instrumentation
	5.13 Signal conditioning
	5.14 Data acquisition
	5.15 Conclusions
6 Online temperature monitoring
	6.1 Introduction
	6.2 Local temperature measurement
	6.3 Hot-spot measurement and thermal images
	6.4 Bulk measurement
	6.5 Conclusions
7 Online chemical monitoring
	7.1 Introduction
	7.2 Insulation degradation
	7.3 Factors that affect detection
	7.4 Insulation degradation detection
		7.4.1 Particulate detection – core monitors
		7.4.2 Particulate detection – chemical analysis
		7.4.3 Gas analysis offline
		7.4.4 Gas analysis online
	7.5 Lubrication oil and bearing degradation
	7.6 Oil degradation detection
	7.7 Wear debris detection
		7.7.1 General
		7.7.2 Ferromagnetic techniques
		7.7.3 Other wear debris detection techniques
	7.8 Conclusions
8 Online vibration monitoring
	8.1 Introduction
	8.2 Stator core response
		8.2.1 General
		8.2.2 Calculation of natural modes
		8.2.3 Stator electromagnetic force wave
	8.3 Stator end winding response
	8.4 Rotor response
		8.4.1 Transverse response
			8.4.1.1 Rigid rotors
			8.4.1.2 Flexible rotors
		8.4.2 Torsional response
	8.5 Bearing response
		8.5.1 General
		8.5.2 Rolling element bearings
		8.5.3 Sleeve bearings
	8.6 Monitoring techniques
		8.6.1 Overall level monitoring
		8.6.2 Frequency spectrum monitoring
		8.6.3 Faults detectable from the stator force wave
		8.6.4 Torsional oscillation monitoring (IAS)
		8.6.5 Shock pulse monitoring
	8.7 Conclusions
9 Online current, flux and power monitoring
	9.1 Introduction
	9.2 Generator and motor stator faults
		9.2.1 Generator stator winding insulation detection
		9.2.2 Stator current monitoring for stator faults
		9.2.3 Brush-gear fault detection
		9.2.4 Rotor-mounted search coils
	9.3 Generator rotor faults
		9.3.1 General
		9.3.2 Earth leakage faults on-line
		9.3.3 Turn-to-turn faults on-line
			9.3.3.1 Air-gap search coils
			9.3.3.2 Circulating current measurement
	9.4 Motor rotor faults
		9.4.1 General
		9.4.2 Air-gap search coils
		9.4.3 Stator current monitoring for rotor faults (MCSA)
		9.4.4 Rotor current monitoring
	9.5 Generator and motor comprehensive methods
		9.5.1 General
		9.5.2 Shaft flux
		9.5.3 Stator and rotor currents
		9.5.4 Power
		9.5.5 Shaft voltage or current
		9.5.6 Mechanical and electrical interaction
	9.6 Conclusions
10 Online partial discharge (PD) electrical monitoring
	10.1 Introduction
	10.2 Background to discharge detection
	10.3 Early discharge detection methods
		10.3.1 RF coupling method
		10.3.2 Earth loop transient method
		10.3.3 Capacitive coupling method
		10.3.4 Wide-band RF method
		10.3.5 Insulation remanent life
	10.4 Detection problems
	10.5 Modern discharge detection methods
	10.6 Conclusions
11 Online variable speed drive machine monitoring
	11.1 Introduction
	11.2 Operation and fault mechanisms
		11.2.1 Insulation degradation mechanisms
		11.2.2 Bearing current discharges
	11.3 Bearing current discharge detection
	11.4 Insulation degradation detection
		11.4.1 PD measurement
		11.4.2 Capacitance and dissipation factor measurement
		11.4.3 Built-in winding insulation degradation detector
	11.5 Control in-loop machine fault detection
	11.6 Conclusions
12 Offline monitoring
	12.1 Introduction
	12.2 Stator core
		12.2.1 General
		12.2.2 Turbo-generators
		12.2.3 Hydro-generators
	12.3 Stator windings
		12.3.1 Summary of offline tests
		12.3.2 Frequency response analysis
	12.4 Rotor windings
		12.4.1 Summary of offline tests
		12.4.2 Synchronous rotor surge tests
	12.5 Conclusions
13 Condition-based maintenance and asset management
	13.1 Introduction
	13.2 Preventative maintenance
	13.3 Condition-based maintenance
		13.3.1 Signals and data for condition-based maintenance
		13.3.2 Targeted monitoring
	13.4 Economics of maintenance strategies
		13.4.1 Basic economic justification
		13.4.2 Life-cycle costing
		13.4.3 Cost–benefit analysis of condition monitoring for CBM
		13.4.4 Asset management
	13.5 Conclusions
14 Application of artificial intelligence techniques to CM
	14.1 Introduction
	14.2 Multi-parameter monitoring
	14.3 Expert systems
	14.4 Fuzzy logic
	14.5 Machine learning using ANNs
		14.5.1 What can be learned for CM?
		14.5.2 Supervised learning through ANN
		14.5.3 Unsupervised learning
	14.6 Deep learning with big data
	14.7 An AI example
		14.7.1 Systems incorporating AI
		14.7.2 How an MBVI system works
		14.7.3 An MBVI system and AI
	14.8 Conclusions
15 Safety, training and qualification
	15.1 Introduction
	15.2 Safety
	15.3 Training and qualification
		15.3.1 Training and qualification categories
		15.3.2 Category I – data collector
		15.3.3 Category II – specialist
		15.3.4 Category III – analyst
		15.3.5 Category IV – expert
	15.4 Conclusions
16 Overall conclusions
	16.1 CM techniques
	16.2 AI and ML
	16.3 Standards, training, safety and qualification
	16.4 The future importance
References
Standards
Appendix A. Failure modes and root causes in the rotating electrical machines
Appendix B. Draft CM good practice guide, MCSA
	B.1 Introduction
		B.1.1 What this series of guides is about
		B.1.2 What this particular guide is about
	B.2 Overall description
	B.3 Scope
	B.4 Expected outputs
	B.5 Controls and capabilities
	B.6 Issues
	B.7 How to apply MCSA
	B.8 Data communication
	B.9 Data interpretation
	B.10 Safety
	B.11 Skills, competence and training
	B.12 Taking readings
Appendix C. Electrical machines, drives and condition monitoring timeline
Index
Back Cover