Page 13 - Handbook of Electrical Engineering

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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