3.45 Figure 3.39 shows a oneline diagram of a system in which the three-phase generator is rated 300 MVA, 20 kV with a subtransient reactance of 0.2 per unit and with its neutral grounded through a 0.4-N reactor. The transmis- sion line is 64 km long with a series reactance of 0.5 N/km. The three-phase transformer T, is rated 350 MVA, 230/ 20 kV with a leakage reactance of 0.1 per unit. Transformer T, is composed of three single-phase transform- ers, each rated 100 MVA, 127/13.2 kV with a leakage reactance of 0.1 per unit. Two 13.2-kV motors M, and M, with a subtransient reactance of 0.2 per unit for each motor represent the load. M, has a rated input of 200 MVA with its neutral grounded through a 0.4-N current-limiting reac- tor. M, has a rated input of 100 MVA with its neutral not connected to ground. Neglect phase shifts associated with the transformers. Choose the generator rating as base in the generator circuit and draw the posi- tive-sequence reactance diagram showing all reactances in per unit. (20 kV) (13.8 kV) Tz FIGURE 3.39 M, (230 kV) Problems 3.45 m3E n 38 M2 and 3.46

3.45 Figure 3.39 shows a oneline diagram of a system in which the three-phase generator is rated 300 MVA, 20 kV with a subtransient reactance of 0.2 per unit and with its neutral grounded through a 0.4-N reactor. The transmis- sion line is 64 km long with a series reactance of 0.5 N/km. The three-phase transformer T, is rated 350 MVA, 230/ 20 kV with a leakage reactance of 0.1 per unit. Transformer T, is composed of three single-phase transform- ers, each rated 100 MVA, 127/13.2 kV with a leakage reactance of 0.1 per unit. Two 13.2-kV motors M, and M, with a subtransient reactance of 0.2 per unit for each motor represent the load. M, has a rated input of 200 MVA with its neutral grounded through a 0.4-N current-limiting reac- tor. M, has a rated input of 100 MVA with its neutral not connected to ground. Neglect phase shifts associated with the transformers. Choose the generator rating as base in the generator circuit and draw the posi- tive-sequence reactance diagram showing all reactances in per unit. (20 kV) (13.8 kV) Tz FIGURE 3.39 M, (230 kV) Problems 3.45 m3E n 38 M2 and 3.46

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

Chapter3: Power Transformers

Section: Chapter Questions

Problem 3.45P: Figure 3.39 shows a oneline diagram of a system in which the three-phase generator is rated 300 MVA,...

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Figure 3.39 shows a oneline diagram of a system in which the three-phase generator is rated 300 MVA, 20 kV with a subtransient reactance of 0.2 per unit and with its neutral grounded through a 0.4- reactor. The transmission line is 64km long with a cries reactance of 0.5-/km. The three-phase transformer T1 is rated 350MVA.230/20kV with a leakage reactance of 0.1 per unit. Transformer T2 is composed of three single-phase transformers, each rated 100 MVA, 127/13.2kV with a leakage reactance of 0.1 per unit. Two 13.2kV motors M1 and M2 with a subtransient reactance of 0.2 per unit for each motor represent the load. M1 has a rated input of 200 MVA with its neutral grounded through a 0.4- current-limiting reactor, M2 has a rated input of 100 MVA with its neutral not connected to ground. Neglect phase shifts associated with the transformers. Choose the generator rating as base in the generator circuit and draw the positive-sequence reactance diagram showing all reactances in per unit.
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