The following test results are obtained for a 3ph, 25 kV, 750MVA, 50 Hz, 3600rpm, star-connected synchronous machines at rated speed. 4 (A) Vu (kV) open-circuit test 1, (A) short-circuit test Vu (kV) air gap line 1500 25 10,000 30 i Determine the unsaturated and saturated values of the synchronous reactance in ohms and pu. If a short-circuit test is performed at constant field current 1500 A but at different speeds; 1000, 2000, 3000 and 3600 rpm. ii Determine the short-circuit current at these speeds above. i. Determine the fieldcurrent if the synchronous machine delivers rated MVA to an infinite bus at0.9 lagging power factor.

The following test results are obtained for a 3ph, 25 kV, 750MVA, 50 Hz, 3600rpm, star-connected synchronous machines at rated speed. 4 (A) Vu (kV) open-circuit test 1, (A) short-circuit test Vu (kV) air gap line 1500 25 10,000 30 i Determine the unsaturated and saturated values of the synchronous reactance in ohms and pu. If a short-circuit test is performed at constant field current 1500 A but at different speeds; 1000, 2000, 3000 and 3600 rpm. ii Determine the short-circuit current at these speeds above. i. Determine the fieldcurrent if the synchronous machine delivers rated MVA to an infinite bus at0.9 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

Chapter7: Symmetrical Faults

Section: Chapter Questions

Problem 7.8P

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