6.4 The following test results are obtained for a 30, 25 kV, 750 MVA, 60 Hz, 3600 rpm, star-connected synchronous machine at rated speed. I(A) 1500 VLL. (kV) open-circuit test 25 I. (A) short-circuit test 10,000 VLL (kV) air gap line 30 (a) Determine the number of poles of the synchronous machine. (b) Determine the unsaturated and saturated values of the synchronous reactance in ohms and per unit. (c) The short-circuit test is performed at constant field current (1500 A) but at different speeds- 1000 rpm, 2000 rpm, 3000 rpm, and 3600 rpm. Determine the short-circuit current at these speeds. (d) Determine the field current if the synchronous machine delivers rated MVA to an infinite bus at 0.9 lagging power factor.

6.4 The following test results are obtained for a 30, 25 kV, 750 MVA, 60 Hz, 3600 rpm, star-connected synchronous machine at rated speed. I(A) 1500 VLL. (kV) open-circuit test 25 I. (A) short-circuit test 10,000 VLL (kV) air gap line 30 (a) Determine the number of poles of the synchronous machine. (b) Determine the unsaturated and saturated values of the synchronous reactance in ohms and per unit. (c) The short-circuit test is performed at constant field current (1500 A) but at different speeds- 1000 rpm, 2000 rpm, 3000 rpm, and 3600 rpm. Determine the short-circuit current at these speeds. (d) Determine the field current if the synchronous machine delivers rated MVA to an infinite bus at 0.9 lagging power factor.

Power System Analysis and Design (MindTap Course List)

6th Edition

ISBN:9781305632134

Author:J. Duncan Glover, Thomas Overbye, Mulukutla S. Sarma

Publisher:J. Duncan Glover, Thomas Overbye, Mulukutla S. Sarma

Chapter12: Power System Controls

Section: Chapter Questions

Problem 12.4P

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