Page 6 - Handbook of Electrical Engineering

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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