Handbook of Electrical Engineering

SYNCHRONOUS GENERATORS AND MOTORS 81 The rotating metal components such as the shaft itself, the rotor poles and the laminations ...

4 Automatic Voltage Regulation 4.1 Modern Practice Most modern synchronous generators are furnished with a self-contained voltag ...

84 HANDBOOK OF ELECTRICAL ENGINEERING Figure 4.1 Control system for the automatic voltage regulation of a synchronous generator. ...

AUTOMATIC VOLTAGE REGULATION 85 is loaded from zero to full-load at rated power factor. In order to achieve this low level of re ...

86 HANDBOOK OF ELECTRICAL ENGINEERING Step 3.Derive the steady state conditions of the AVR for no load and full-load on the gene ...

AUTOMATIC VOLTAGE REGULATION 87 Equate the bracketed terms in (4.5) and (4.6) Gg Vref V 1 −Gg=Vref− 1. 0 Hence, Vref= (Gg− 1. 0 ...

88 HANDBOOK OF ELECTRICAL ENGINEERING more damping feedback will be required. Hence the values ofKfandTf 2 will tend towards the ...

AUTOMATIC VOLTAGE REGULATION 89 to the busbars, falls to near zero when the short circuit exists. The AVR may loose its supply d ...

90 HANDBOOK OF ELECTRICAL ENGINEERING Figure 4.2 Open circuit voltage versus exciter field voltage. The graph shows the effect o ...

AUTOMATIC VOLTAGE REGULATION 91 The output signals from the saturation block are therefore, Va 1 −Vfd 1 =AeBVf d^1 (4.9) And Va ...

92 HANDBOOK OF ELECTRICAL ENGINEERING 4.2.1 Worked example An exciter has an open-circuit curve which has the following two pair ...

AUTOMATIC VOLTAGE REGULATION 93 4.2.3 Determining of saturation constants Saturation data for exciters and main generators can b ...

94 HANDBOOK OF ELECTRICAL ENGINEERING Figure 4.5 Open-circuit voltage in per unit versus exciter field voltage in per unit. For ...

AUTOMATIC VOLTAGE REGULATION 95 And, S 3 = ( Va 31 −Va 32 Va 12 Vfd3pu ) u=AeBVf d^3 (4.21) Divide (4.21) by (4.20) S 3 S 2 =eB( ...

96 HANDBOOK OF ELECTRICAL ENGINEERING Returning to (4.22) and substitutingu, Vfd 3 −Vfd 2 = ( u− 1 u ) Vfd 3 And so, B= 1 Vfd 3 ...

AUTOMATIC VOLTAGE REGULATION 97 Table 4.3. Typical data for AVR control systems Parameter Low Values Typical High Ga 250 500 150 ...

5 Induction Motors 5.1 Principle of Operation of the Three-Phase Motor In the form used for industrial drives, induction motors ...

100 HANDBOOK OF ELECTRICAL ENGINEERING a) The rotor impedance increases. b) The rotor emf reduces. These effects result in the s ...

INDUCTION MOTORS 101 Figure 5.1 Commonly used equivalent circuit of an induction motor. so that the calculated efficiency and po ...

102 HANDBOOK OF ELECTRICAL ENGINEERING of the rotor bars. The functionsR 2 (s)andX 2 (s)can be approximated by the following sim ...