A 50HZ turbo generator is rated 500MVA, 22KV, and its reactances are X"d=X2 = 0.15PU and Xo = 0.05PD. It is Y-connected, solidly grounded and is operating at rated voltage at no load. A) Determine the three phase fault current occurs on the terminal of generator. B) How many ohms of resistance in the neutral connection of the generator would limit the sub transient line current for a single line to ground fault to that for a three phase fault.

A 50HZ turbo generator is rated 500MVA, 22KV, and its reactances are X"d=X2 = 0.15PU and Xo = 0.05PD. It is Y-connected, solidly grounded and is operating at rated voltage at no load. A) Determine the three phase fault current occurs on the terminal of generator. B) How many ohms of resistance in the neutral connection of the generator would limit the sub transient line current for a single line to ground fault to that for a three phase fault.

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

Chapter11: Transient Stability

Section: Chapter Questions

Problem 11.8P

See similar textbooks

Similar questions

Three single-phase two-winding transformers, each rated 3kVA,220/110volts,60Hz, with a 0.10 per-unit leakage reactance, are connected as a three-phase extended autotransformer bank, as shown in Figure 3.36(c). The low-voltage winding has a 110 volt rating. (a) Draw the positive-sequence phasor diagram and show that the high-voltage winding has a 479.5 volt rating. (b) A three-phase load connected to the low-voltage terminals absorbs 6 kW at 110 volts and at 0.8 power factor lagging. Draw the per-unit impedance diagram and calculate the voltage and current at the high-voltage terminals. Assume positive-sequence operation.
Consider a three-phase generator rated 300MVA,23kV, supplying a system load of 240 MA and 0.9 power factor lagging at 230 kV through a 330MVA,23/230Y-kV step-up transformer with a leakage reactance of 0.11 per unit. (a) Neglecting the exciting current and choosing base values at the load of 100 MVL and 230 kV. Find the phasor currents IA,IB, and IC supplied to the load in per unit. (b) By choosing the load terminal voltage IA as reference, specify the proper base for the generator circuit and determine the generator voltage V as well as the phasor currents IA,IB, and IC, from the generator. (Note: Take into account the phase shift of the transformer.) (C) Find the generator terminal voltage in kV and the real power supplied by the generator in MW. (d) By omitting the transformer phase shift altogether, check to see whether you get the same magnitude of generator terminal voltage and real power delivered by the generator.
With the same transformer banks as in Problem 3.47, Figure 3.41 shows the oneline diagram of a generator, a step-up transformer bank, a transmission line, a stepown transformer bank, and an impedan load. The generator terminal voltage is 15 kV (line-to-line). (a) Draw the per-phase equivalent circuit, aounting for phase shifts for positive-sequence operation. (b) By choosing the line-to-neutral generator terminal voltage as the reference, determine the magnitudes of the generator current, transmiss ion-line current, load current, and line-to-line load voltage. Also, find the three-phase complex power delivered to the load.
The motors M1andM2 of Problem 3.45 have inputs of 120 and 60 MW, respectively, at 13.2 kV, and both operate at unity power factor. Determine the generator terminal voltage and voltage regulation of the line. Neglect transformer phase shifts.
1) A 50 Hz, 3.75 MVA, 3.18 kV, three-phase synchronous generator with rated (nominal) currentof In = 682 A has open- and short-circuit characteristic listed in Table 1 and Table 2 respectively.Determine saturated and unsaturated synchronous reactance in per-unit and in Ohms and calulateshort circuit ratio (SCR). The generator is delivering rated power at 0.95 power factor leading atthe rated therminal voltage. Using given open-circuit characteristic approximately determine thefield current under rated loading.
A three phase synchronous generator with negligible resistance and Xs=20 ohm has induced voltage as well as terminal voltage per phase equal to 230 V. for the load angle of 30o, power received by the bus is .........W.
A three-phase, 250 MVA, 16 kV rated synchronous generator is feeding into an infinite bus bar at 15 kV. The generator has a synchronous reactance of 1.62 pu. It is found that the machine excitation and mechanical power input are adjusted to give E = 24 kV and power angle δ = 30 degree. a) Determine the line current and active and reactive power fed to the generator terminal. b) The mechanical power input to the generator is increased by 20% from that in part (a) but its excitation is not changed. Find the new line current and power factor. c) With reference to part (a) current is to be reduced by 20% at the same power factor by adjusting mechanical power input to the generator and its excitation. Determine E, angle δ and mechanical power input. d) With the reduced current as in part (c), the power is to be delivered to generator terminal at unity power factor, what are the corresponding values of E and δ and also the mechanical power input to the generator. Per-unit values are given on…
A three-phase, 250 MVA, 16 kV rated synchronous generator is feeding into an infinite bus bar at 15 kV. The generator has a synchronous reactance of 1.62 pu. It is found that the machine excitation and mechanical power input are adjusted to give E = 24 kV and power angle δ = 30◦. a) Determine the line current and active and reactive power fed to the generator terminal. b) The mechanical power input to the generator is increased by 20% from that in part (a) but its excitation is not changed. Find the new line current and power factor. c) With reference to part (a) current is to be reduced by 20% at the same power factor by adjusting mechanical power input to the generator and its excitation. Determine E, angle δand mechanical power input.
A three-phase, 250 MVA, 16 kV rated synchronous generator is feeding into an infinite bus bar at 15 kV. The generator has a synchronous reactance of 1.62 pu. It is found that the machine excitation and mechanical power input are adjusted to give E = 24 kV and power angle δ = 30◦. a) Determine the line current and active and reactive power fed to the generator terminal. b) With reference to part (a) current is to be reduced by 20% at the same power factor by adjusting mechanical power input to the generator and its excitation. Determine E, angle δ and mechanical power input. c) With the reduced current as in part (c), the power is to be delivered to generator terminal at unity power factor, what are the corresponding values of E and δ and also the mechanical power input to the generator. Per-unit values are given on machine rating as the base.
A 60-MVA, 69.3 kV, 3-phase synchronous generator has a synchronous reactance of 15 ohms per phase and negligible resistance. The generator is delivering rated power at 0.8 pf leading at rated terminal voltage to an infinite bus bar. Determine the magnitude of the power angle. Please give a clear solution and box the final answer Subject Electrical machine 2
Calculate the per unit impedance of a three-phase generator with a power rating of 900 KVA and voltage rating of 33 KV. The generator has an armature resistance of 40 Ohms per phase and a synchronous reactance of 140 Ohms per phase.
The effective resistance of a 2200 V, 50 Hz, 440 KVA, 1 -phase alternator is 0.5 ohm. On short-circuit, a field current of 40 A gives the full load current of 200 AS. The electromotive force on open-circuits with same field excitation is 1160 V. Then the synchronous impedance and reactance is _______ ohm and _______ ohm respectively.