A practical treatment of power system design within the oil, gas, petrochemical and offshore industries. These have significantly different characteristics to large-scale power generation and long distance public utility industries. Developed from a series of lectures on electrical power systems given to oil company staff and university students, Sheldrake's work provides a careful balance between sufficient mathematical theory and comprehensive practical application knowledge. Features of the text include: * Comprehensive handbook detailing the application of electrical engineering to the oil, gas and petrochemical industries * Practical guidance to the electrical systems equipment used on off-shore production platforms, drilling rigs, pipelines, refineries and chemical plants * Summaries of the necessary theories behind the design together with practical guidance on selecting the correct electrical equipment and systems required * Presents numerous 'rule of thumb' examples enabling quick and accurate estimates to be made * Provides worked examples to demonstrate the topic with practical parameters and data * Each chapter contains initial revision and reference sections prior to concentrating on the practical aspects of power engineering including the use of computer modelling * Offers numerous references to other texts, published papers and international standards for guidance and as sources of further reading material * Presents over 35 years of experience in one self-contained reference * Comprehensive appendices include lists of abbreviations in common use, relevant international standards and conversion factors for units of measure An essential reference for electrical engineering designers, operations and maintenance engineers and technicians.

Table of Contents:
Foreword xix Preface xxi Acknowledgements xxiii About the Author xxv 1 Estimation of Plant Electrical Load 1 1.1 Preliminary Single-Line Diagrams 1 1.2 Load Schedules 2 1.2.1 Worked example 5 1.3 Determination of Power Supply Capacity 8 1.4 Standby Capacity of Plain Cable Feeders and Transformer Feeders 12 1.5 Rating of Generators in Relation to their Prime Movers 13 1.5.1 Operation at low ambient temperatures 13 1.5.2 Upgrading of prime movers 13 1.6 Rating of Motors in Relation to their Driven Machines 13 1.7 Development of Single-Line Diagrams 14 1.7.1 The key single line diagram 15 1.7.2 Individual switchboards and motor control centres 15 1.8 Coordination with other Disciplines 16 1.8.1 Process engineers 16 1.8.2 Mechanical engineers 17 1.8.3 Instrument engineers 17 1.8.4 Communication and safety engineers 18 1.8.5 Facilities and operations engineers 18 Reference 18 2 Gas Turbine Driven Generators 19 2.1 Classification of Gas Turbine Engines 19 2.1.1 Aero-derivative gas turbines 19 2.1.2 Light industrial gas turbines 20 2.1.3 Heavy industrial gas turbines 20 2.1.4 Single and two-shaft gas turbines 20 2.1.5 Fuel for gas turbines 23 2.2 Energy Obtained from a Gas Turbine 23 2.2.1 Effect of an inefficient compressor and turbine 29 2.2.2 Maximum work done on the generator 30 2.2.3 Variation of specific heat 31 2.2.4 Effect of ducting pressure drop and combustion chamber pressure drop 32 2.2.5 Heat rate and fuel consumption 35 2.3 Power Output from a Gas Turbine 36 2.3.1 Mechanical and electrical power losses 37 2.3.2 Factors to be considered at the design stage of a power plant 37 2.4 Starting Methods for Gas Turbines 39 2.5 Speed Governing of Gas Turbines 39 2.5.1 Open-loop speed-torque characteristic 39 2.5.2 Closed-loop speed-power characteristic 41 2.5.3 Governing systems for gas turbines 43 2.5.4 Load sharing between droop-governed gas turbines 44 2.5.5 Load sharing controllers 50 2.6 Mathematical Modelling of Gas Turbine Speed Governing Systems 52 2.6.1 Modern practice 52 2.6.2 Typical parameter values for speed governing systems 59 References 59 Further Reading 59 3 Synchronous Generators and Motors 61 3.1 Common Aspects Between Generators and Motors 61 3.2 Simplified Theory of Operation of a Generator 61 3.2.1 Steady state armature reaction 62 3.2.2 Transient state armature reaction 63 3.2.3 Sub-transient state armature reaction 63 3.3 Phasor Diagram of Voltages and Currents 64 3.4 The Derived Reactances 65 3.4.1 Sensitivity of X md , X a , X f and X kd to Changes in Physical dimensions 67 3.5 Active and Reactive Power Delivered from a Generator 68 3.5.1 A general case 68 3.5.2 The particular case of a salient pole generator 70 3.5.3 A simpler case of a salient pole generator 71 3.6 The Power Versus Angle Chart of a Salient Pole Generator 72 3.7 Choice of Voltages for Generators 73 3.8 Typical Parameters of Generators 73 3.9 Construction Features of High Voltage Generators and Induction Motors 78 3.9.1 Enclosure 78 3.9.2 Reactances 79 3.9.3 Stator windings 79 3.9.4 Terminal boxes 80 3.9.5 Cooling methods 80 3.9.6 Bearings 80 References 81 4 Automatic Voltage Regulation 83 4.1 Modern Practice 83 4.1.1 Measurement circuits 83 4.1.2 Error sensing circuit 84 4.1.3 Power amplifier 84 4.1.4 Main exciter 88 4.2 IEEE Standard AVR Models 89 4.2.1 Worked example 92 4.2.2 Worked example 92 4.2.3 Determining of saturation constants 93 4.2.4 Typical parameter values for AVR systems 97 Reference 97 5 Induction Motors 99 5.1 Principle of Operation of the Three-Phase Motor 99 5.2 Essential Characteristics 100 5.2.1 Motor torque versus speed characteristic 100 5.2.2 Motor starting current versus speed characteristic 107 5.2.3 Load torque versus speed characteristic 108 5.2.4 Sensitivity of characteristics to changes in resistances and reactances 109 5.2.5 Worked example 109 5.2.6 Typical impedance data for two-pole and four-pole induction motors 114 5.2.7 Representing the deep-bar effect by two parallel branches 114 5.3 Construction of Induction Motors 119 5.4 Derating Factors 121 5.5 Matching the Motor Rating to the Driven Machine Rating 121 5.6 Effect of the Supply Voltage on Ratings 122 5.7 Effect of the System Fault Level 123 5.8 Cable Volt-drop Considerations 123 5.9 Critical Times for Motors 125 5.10 Methods of Starting Induction Motors 125 5.10.1 Star-delta method 126 5.10.2 Korndorfer auto-transformer method 126 5.10.3 Soft-start power electronics method 127 5.10.4 Series reactor method 128 5.10.5 Part winding method 129 References 129 6 Transformers 131 6.1 Operating Principles 131 6.2 Efficiency of a Transformer 134 6.3 Regulation of a Transformer 135 6.4 Three-Phase Transformer Winding Arrangements 136 6.5 Construction of Transformers 137 6.5.1 Conservator and sealed type tanks 139 6.6 Transformer Inrush Current 140 References 142 7 Switchgear and Motor Control Centres 143 7.1 Terminology in Common Use 143 7.2 Construction 144 7.2.1 Main busbars 144 7.2.2 Earthing busbars 146 7.2.3 Incoming and busbar section switching device 146 7.2.4 Forms of separation 147 7.2.5 Ambient temperature derating factor 149 7.2.6 Rated normal current 149 7.2.7 Fault making peak current 149 7.2.8 Fundamental AC part 150 7.2.9 DC part 150 7.2.10 Double frequency AC part 150 7.2.11 Fault breaking current 152 7.2.12 Fault withstand duty 153 7.3 Switching Devices 154 7.3.1 Outgoing switching device for switchgear 154 7.3.2 Outgoing switching device for motor control centres 155 7.4 Fuses for Motor Control Centre Outgoing Circuits 156 7.5 Safety Interlocking Devices 157 7.6 Control and Indication Devices 158 7.6.1 Restarting and reaccelerating of motors 158 7.6.2 Micro-computer based systems 159 7.7 Moulded Case Circuit Breakers 162 7.7.1 Comparison with fuses 162 7.7.2 Operating characteristics 163 7.7.3 Cut-off current versus prospective current 164 7.7.4 i-squared-t characteristic 164 7.7.5 Complete and partial coordination of cascaded circuit breakers 165 7.7.6 Worked example for coordination of cascaded circuit breakers 167 7.7.7 Cost and economics 172 References 172 8 Fuses 173 8.1 General Comments 173 8.2 Operation of a Fuse 174 8.3 Influence of the Circuit X-to-R Ratio 174 8.4 The I 2 t Characteristic 176 8.4.1 Worked example 179 References 181 9 Cables, Wires and Cable Installation Practices 183 9.1 Electrically Conducting Materials used in the Construction of Cables 183 9.1.1 Copper and aluminium 184 9.1.2 Tin 184 9.1.3 Phosphor bronze 185 9.1.4 Galvanised steel 185 9.1.5 Lead 186 9.2 Electrically Non-Conducting Materials used in the Construction of Cables 187 9.2.1 Definition of basic terminology 187 9.3 Composition of Power and Control Cables 191 9.3.1 Compositional notation 192 9.3.2 Conductor 192 9.3.3 Conductor semiconducting screen 196 9.3.4 Insulation 196 9.3.5 Insulation semiconductor screen 197 9.3.6 Inner sheath 197 9.3.7 Lead sheathing 197 9.3.8 Armouring 198 9.3.9 Outer sheath 198 9.4 Current Ratings of Power Cables 198 9.4.1 Continuous load current 198 9.4.2 Continuous rated current of a cable 199 9.4.3 Volt-drop within a cable 209 9.4.4 Protection against overloading current 242 9.5 Cables with Enhanced Performance 244 9.5.1 Fire retardance 244 9.5.2 Fire resistance 245 9.5.3 Emission of toxic gases and smoke 245 9.5.4 Application of fire retardant and fire resistant cables 246 Reference 247 10 Hazardous Area Classification and the Selection of Equipment 249 10.1 Historical Developments 249 10.2 Present Situation 249 10.3 Elements of Hazardous Area Classification 251 10.3.1 Mixtures of gases, vapours and air 251 10.4 Hazardous Area Zones 253 10.4.1 Non-hazardous area 253 10.4.2 Zone 2 hazardous area 253 10.4.3 Zone 1 hazardous area 253 10.4.4 Zone 0 hazardous area 254 10.4.5 Adjacent hazardous zones 254 10.5 Types of Protection for Hazardous Areas 254 10.5.1 Type of protection ‘d’ 255 10.5.2 Type of protection ‘e’ 256 10.5.3 Type of protection ‘i’ 256 10.5.4 Type of protection ‘m’ 257 10.5.5 Type of protection ‘n’ and ‘n’ 257 10.5.6 Type of protection ‘o’ 258 10.5.7 Type of protection ‘p’ 258 10.5.8 Type of protection ‘q’ 259 10.5.9 Type of protection ‘s’ 259 10.5.10 Type of protection ‘de’ 259 10.6 Types of Protection for Ingress of Water and Solid Particles 260 10.6.1 European practice 260 10.6.2 American practice 261 10.7 Certification of Hazardous Area Equipment 265 10.8 Marking of Equipment Nameplates 266 References 266 Further Reading 266 11 Fault Calculations and Stability Studies 269 11.1 Introduction 269 11.2 Constant Voltage Source – High Voltage 269 11.3 Constant Voltage Source – Low Voltage 271 11.4 Non-Constant Voltage Sources – All Voltage Levels 273 11.5 Calculation of Fault Current due to Faults at the Terminals of a Generator 274 11.5.1 Pre-fault or initial conditions 274 11.5.2 Calculation of fault current – RMS symmetrical values 276 11.6 Calculate the Sub-Transient symmetrical RMS Fault Current Contributions 279 11.6.1 Calculate the sub-transient peak fault current contributions 281 11.7 Application of the Doubling Factor to Fault Current I′′frms  found in 11.6 287 11.7.1 Worked example 288 11.7.2 Breaking duty current 291 11.8 Computer Programs for Calculating Fault Currents 292 11.8.1 Calculation of fault current – RMS and peak asymmetrical values 292 11.8.2 Simplest case 293 11.8.3 The circuit x-to-r ratio is known 293 11.8.4 Detailed generator data is available 293 11.8.5 Motor contribution to fault currents 293 11.9 The use of Reactors 294 11.9.1 Worked example 297 11.10 Some Comments on the Application of IEC60363 and IEC 60909 300 11.11 Stability Studies 300 11.11.1 Steady state stability 301 11.11.2 Transient stability 303 References 308 Further Reading 309 12 Protective Relay Coordination 311 12.1 Introduction to Overcurrent Coordination 311 12.1.1 Relay notation 313 12.2 Generator Protection 313 12.2.1 Main generators 313 12.2.2 Overcurrent 314 12.2.3 Differential stator current relay 318 12.2.4 Field failure relay 319 12.2.5 Reverse active power relay 321 12.2.6 Negative phase sequence relay 322 12.2.7 Stator earth fault relays 322 12.2.8 Over terminal voltage 324 12.2.9 Under terminal voltage 324 12.2.10 Under- and overfrequency 325 12.3 Emergency Diesel Generators 325 12.4 Feeder Transformer Protection 326 12.4.1 Overcurrent 329 12.4.2 High-set or instantaneous current 330 12.4.3 Characteristics of the upstream source 332 12.5 Feeder Cable Protection 332 12.5.1 Overcurrent protection 332 12.5.2 Short-circuit protection 333 12.5.3 Earth fault protection 333 12.6 Busbar Protection in Switchboards 334 12.6.1 Busbar zone protection 334 12.6.2 Overcurrent protection 335 12.6.3 Undervoltage protection 335 12.7 High Voltage Induction Motor Protection 336 12.7.1 Overloading or thermal image 337 12.7.2 Instantaneous or high-set overcurrent 339 12.7.3 Negative phase sequence 339 12.7.4 Core balance earth fault 340 12.7.5 Differential stator current 340 12.7.6 Stalling current 340 12.7.7 Limitation to the number of successive starts 341 12.7.8 Undercurrent 341 12.7.9 High winding temperature 342 12.7.10 High bearing temperature 342 12.7.11 Excessive vibration 342 12.8 Low Voltage Induction Motor Protection 342 12.8.1 Overloading or thermal image 343 12.8.2 Instantaneous or high-set overcurrent 344 12.8.3 Negative phase sequence 344 12.8.4 Core balance earth fault 345 12.8.5 Stalling current 345 12.8.6 Limitation to the number of successive starts 345 12.9 Low Voltage Static Load Protection 345 12.9.1 Time-delayed overcurrent 346 12.9.2 Instantaneous or high-set overcurrent 346 12.9.3 Core balance earth fault 346 12.10 Mathematical Equations for Representing Standard, Very and Extremely Inverse Relays 346 References 349 13 Earthing and Screening 351 13.1 Purpose of Earthing 351 13.1.1 Electric shock 351 13.1.2 Damage to equipment 353 13.1.3 Zero reference potential 353 13.2 Site Locations 353 13.2.1 Steel structures 354 13.2.2 Land-based plants 354 13.2.3 Concrete and brick-built structures 356 13.3 Design of Earthing Systems 356 13.3.1 High voltage systems 356 13.3.2 Low voltage three-phase systems 357 13.3.3 IEC types of earthing systems 360 13.3.4 Earth loop impedance 365 13.3.5 Earthing rods and grids 367 13.4 Construction Details Relating to Earthing 371 13.4.1 Frames, casings and cubicle steelwork 371 13.4.2 Screwed and clearance hole entries 371 13.4.3 Earthing only one end of a cable 372 13.5 Screening and Earthing of Cables used in Electronic Circuits 373 13.5.1 Capacitance and inductance mechanisms 373 13.5.2 Screening against external interference 374 13.5.3 Earthing of screens 379 13.5.4 Screening of high frequencies 380 13.5.5 Power earths, cubicle and clean earths 381 References 383 14 Variable Speed Electrical Drivers 385 14.1 Introduction 385 14.1.1 Environment 386 14.1.2 Power supply 386 14.1.3 Economics 387 14.2 Group 1 Methods 388 14.2.1 Simple variable voltage supplies 388 14.2.2 Pole-changing of the stator winding 389 14.2.3 Pole amplitude modulated motors 390 14.2.4 Wound rotor induction motors 391 14.3 Group 2 Methods 392 14.3.1 Variable voltage constant frequency supply 392 14.3.2 Variable frequency variable voltage supply 392 14.4 Variable Speed DC Motors 394 14.5 Electrical Submersible Pumps 394 14.5.1 Introduction 394 14.5.2 Electrical submersible pump construction 395 14.6 Control Systems for AC Motors 397 References 400 15 Harmonic Voltages and Currents 401 15.1 Introduction 401 15.2 Rectifiers 402 15.2.1 Diode bridges 402 15.2.2 Thyristor bridges 404 15.2.3 Power transistor bridges 407 15.2.4 DC motors 407 15.3 Harmonic Content of the Supply Side Currents 413 15.3.1 Simplified waveform of a six-pulse bridge 413 15.3.2 Simplified commutation delay 414 15.3.3 Fourier coefficients of the line current waveform 414 15.3.4 Simplified waveform of a 12-pulse bridge 417 15.4 Inverters 421 15.4.1 Basic method of operation 421 15.4.2 Three-phase power inversion 422 15.4.3 Induction motor fed from a voltage source inverter 423 15.5 Filtering of Power Line Harmonics 429 15.6 Protection, Alarms and Indication 433 References 433 16 Computer Based Power Management Systems 435 16.1 Introduction 435 16.2 Typical Configurations 435 16.3 Main Functions 436 16.3.1 High-speed load shedding 436 16.3.2 Load shedding priority table 439 16.3.3 Low-speed load shedding 440 16.3.4 Inhibiting the starting of large motors 441 16.3.5 VDU display of one-line diagrams 442 16.3.6 Active power sharing for generators 443 16.3.7 Isochronous control of system frequency 443 16.3.8 Reactive power sharing for generators 444 16.3.9 Isochronous control of busbar voltage 444 16.3.10 Condition monitoring of the gas turbines 444 16.3.11 Scheduling the starting up and shutting down of the main generators 445 16.3.12 Control of the reacceleration of motor loads 446 16.3.13 Auto-synchronising of the main generators 447 16.3.14 Data logging, archiving, trending display, alarms, messages and status reporting 448 17 Uninterruptible Power Supplies 449 17.1 AC Uninterruptible Power Supplies 449 17.1.1 The inverter 449 17.1.2 Coordination of the sub-circuit rated current with the inverter rated current 450 17.1.3 Earth fault leakage detection 451 17.2 DC Uninterruptible Power Supplies 451 17.2.1 UPS battery chargers 452 17.2.2 Batteries 455 17.3 Redundancy Configurations 457 References 458 18 Miscellaneous Subjects 459 18.1 Lighting Systems 459 18.1.1 Types of lighting fittings 461 18.1.2 Levels of illumination 461 18.2 Navigation Aids 463 18.2.1 Flashing marker lights 463 18.2.2 White and red flashing lights 464 18.2.3 Navigation buoys 465 18.2.4 Identification panels 465 18.2.5 Aircraft hazard lighting 465 18.2.6 Helicopter landing facilities 466 18.2.7 Radar 466 18.2.8 Radio direction-finder 466 18.2.9 Sonar devices 467 18.3 Cathodic Protection 467 References 468 19 Preparing Equipment Specifications 469 19.1 The Purpose of Specifications 469 19.2 A Typical Format for a Specification 470 19.2.1 Introduction 471 19.2.2 Scope of supply 471 19.2.3 Service and environmental conditions 471 19.2.4 Compliant international standards 471 19.2.5 Definition of technical and non-technical terms 471 19.2.6 Performance or functional requirements 472 19.2.7 Design and construction requirements 473 19.2.8 Inspection and testing 474 19.2.9 Spare parts 475 19.2.10 Documentation 475 19.2.11 Appendices 477 20 Summary of the Generalised Theory of Electrical Machines as Applied to Synchronous Generators and Induction Motors 479 20.1 Introduction 479 20.2 Synchronous Generator 480 20.2.1 Basic mathematical transformations 483 20.3 Some Notes on Induction Motors 490 20.3.1 Derived reactances 491 20.3.2 Application of three-phase short circuit 491 20.3.3 Derived reactances and time constants for an induction motor 493 20.3.4 Derivation of an equivalent circuit 495 20.3.5 ‘Re-iteration or recapitulation’ 496 20.3.6 Contribution of three-phase short-circuit current from induction motor 501 References 504 Further Reading 505 Appendix A Abbreviations Commonly used in Electrical Documents 507 Appendix B A List of Standards Often Used for Designing Electrical Systems and for Specifying Equipment 517 B. 1 International Electro-technical Commission (Europe) 517 B. 2 Institute of Petroleum (UK) 525 B. 3 International Standards Organisation (Worldwide) 526 B. 4 British Standards Institution (UK) 526 B. 5 American Petroleum Institute (USA) 530 B. 6 Counseil International des Grands Reseaux Electriques (France) 530 B. 7 Engineering Equipment and Materials Users Association (UK) 530 B. 8 Electricity Council (UK) 531 B. 9 Verband Deutscher Electrechniker (Germany) 531 B.10 Institute of Electronic and Electrical Engineers Inc. (USA) 531 B.11 Miscellaneous References from the UK 532 Appendix C Numbering System for Protective Devices, Control and Indication Devices for Power Systems 533 C. 1 Application of Protective Relays, Control and Alarm Devices for Power System Circuits 533 C.1.1 Notes to sub-section C. 1 535 C. 2 Electrical Power System Device Numbers and Functions 536 Appendix D Under-Frequency and Over-Temperature Protection of Gas-Turbine Driven Generators 539 Appendix E List of Document Types to be Produced During a Project 545 E. 1 Contractors Documents 546 E.1.1 Feasibility studies 546 E.1.2 Conceptual design 546 E.1.3 Detail design 547 E. 2 Manufacturers Documents 549 E.2.1 Feasibility studies 549 E.2.2 Conceptual design 549 E.2.3 Detail design 549 Appendix F Worked Example for Calculating the Performance of a Gas Turbine 551 F. 1 The Requirements and Data Given 551 F. 2 Basic Requirements 551 F. 3 Detailed Requirements 552 F. 4 Basic Solutions 552 F. 5 Detailed Solutions 553 Appendix G Worked Example for the Calculation of Volt-drop in a Circuit Containing an Induction Motor 559 G.1 Introduction 559 Appendix H Worked Example for the Calculation of Earthing Current and Electric Shock Hazard Potential Difference in a Rod and Grid Earthing System 585 H.1 Worked Example 585 Appendix I Conversion Factors for the SI System of Units 597 I. 1 Fundamental SI Units 597 I. 2 Derived Non-electrical Units 597 I. 3 Derived Electrical Units 598 I. 4 Conversions 598 I.4. 1 Length 598 I.4. 2 Area 599 I.4. 3 Volume 599 I.4.4 Mass and density 600 I.4. 5 Velocity and acceleration 600 I.4.6 Force 601 I.4. 7 Torque 601 I.4. 8 Power 601 I.4. 9 Energy and work 601 I.4.10 Pressure 602 I.4.11 Moment of inertia and momentum 603 I.4.12 Illumination 603 I.4.13 Electricity and magnetism 604 I.4.14 Miscellaneous quantities 604 I. 5 International Standards Organisation (ISO) Conditions 605 I. 6 Standard Temperature and Pressure (STP) Conditions 605 I. 7 Regularly Used Constants 605 I. 8 Regularly Used Prefixes 606 I. 9 References 606 Index 607