A three-phase synchronous generator is rated 60 MVA, 11 kV. It has an armature resistance ra = 0.1 pu and synchronous reactance xS = 1.65 pu. It is feeding into an inﬁnite bus at 11 kV delivering a current 15 kA at 0.9 power factor lagging. (a) Determine internal voltage (E) and power angle (δ). (b)Draw a vector diagram for this operation and state operating mode of the generator. (c) Infinite bus voltage falls to 10 kV while the mechanical power input to generator and its excitation remains unchanged. What is the value of the current, power factor and reactive power delivered to the infinite bus. Per-unit values are given on machine rating as the base.

A three-phase synchronous generator is rated 60 MVA, 11 kV. It has an armature resistance ra = 0.1 pu and synchronous reactance xS = 1.65 pu. It is feeding into an inﬁnite bus at 11 kV delivering a current 15 kA at 0.9 power factor lagging. (a) Determine internal voltage (E) and power angle (δ). (b)Draw a vector diagram for this operation and state operating mode of the generator. (c) Infinite bus voltage falls to 10 kV while the mechanical power input to generator and its excitation remains unchanged. What is the value of the current, power factor and reactive power delivered to the infinite bus. Per-unit values are given on machine rating as the base.

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

Chapter6: Power Flows

Section: Chapter Questions

Problem 6.47P

See similar textbooks

Similar questions

3.) A 3-phase synchronous generator, rated 16 kV and 200 MVA, has negligible losses and synchronous reactance of 1.65 per unit. It is operated on an infinite bus having a voltage of 15 kV and delivers 100 MVA at 0.8 pf lagging. Solve the internal voltage. Subject Electrical machine 2
A single phase autosequential CFI is fed from a 220 Vde source, R_{L} = 10Omega the thyristor turn off tq time equals to 20 us and frequency is 50 Hz. Determine suitable value of source inductance assuming a maximum current change di/dt of 0.5A per cycle. Neglecting all losses, calculate able the value of operating capacitor C.
A 3-phase, 420 V, 60 Hz, Y-connected synchronous generator, with a synchronous reactance of 1.20 Ohm per phase is connected to an infinite bus. The power angle, when supplying 110 kW to the bus is 30 degree. What will be the total apparent power (in kVA) injected by this generator to infinite bus? (a) 118.28 (c) 110.52 (b) 118.74 (d) 100.39
A turbine has a power coefficient equal to 0.3 when the wind speed is 7 m / s. This turbine is coupled, through a multiplier, to an asynchronous generator of rotor in cage which, in turn, is connected to the distribution network. Considering the data, Air density: 1.25 kg / m3 Blade radius: 15 m Multiplier coefficient: 50 Number of asynchronous generator's pole pairs: 2 Mains frequency: 60 Hz 1% slip Calculate the speed of the turbine rotor (rpm). Is it considered fast or slow?
A440V,22.5-hp,50Hz,3-phase,4-pole,star-connectedinductionmotorhasthefollowing impedances in ohms per phase referred to the stator circuit:R1 = 0.55Ω R2 = 0.35ΩX1 = 1.105Ω X2 = 0.456Ω XM = 27.1ΩThe total rotational losses are 1105 W and are assumed to be constant. The core loss is lumped in with the rotational losses. For a rotor slip of 2.3% at the rated voltage and rated frequency, calculate:d) Electrical power, e) Output power,f) Efficiency.
A440V,22.5-hp,50Hz,3-phase,4-pole,star-connectedinductionmotorhasthefollowing impedances in ohms per phase referred to the stator circuit:R1 = 0.55Ω R2 = 0.35ΩX1 = 1.105Ω X2 = 0.456Ω XM = 27.1ΩThe total rotational losses are 1105 W and are assumed to be constant. The core loss is lumped in with the rotational losses. For a rotor slip of 2.3% at the rated voltage and rated frequency, calculate:g) The shaft torque of the motor at rated load
A 3 phase, wye-connected salient-pole generator has on per phase basis Xd = 2 ohms, Xq = 1.5 ohms and R∅ = 0. When delivering its maximum power output to an infinite bus bar, the terminal and excitation voltages/phase are 1,430 V and 1,495 V, respectively. Find the power angle in electrical degrees at the above conditions
A three-phase synchronous generator has a synchronous reactance of 50 Ω/phase. It is connected to an infinite bus of line voltage 15,000 V , and it develops a total power of 5 MVA supplying with unity pf. If the armature voltage of the generator is increased by 15%, while the input power to the generator remains constant, determine the new power factor and the apparent power supplied to the grid.it supplies to the network.
A three phase, 600kVA, 3.3kV star connected S.G having ????= 0.41Ω/phase. Find the synchronous reactance of generator if the full load of unity power factor is suddenly removed causing the terminal voltage to be increased by 5%.
A 3phase star-connected alternator is rated at 1600 kVA, 13,500V. The armature effective resistance and synchronous reactance are 1.5Ω and 30 Ω respectively per phase. Calculate the percentage regulation for a load of 1280 kW at power factors of (a) 0.8 leading and (b) 0.85 lagging.
A synchronous generator has the following ratings: 3 phase apparent power, 250MVA,13.8kV (L-L, RMS), 0.85 PF, 60Hz, round rotor. Xs = 1.2 pu om the machine's rating base. a) If the torque is reduced by 15% by reducing the mechanical input but the field current is leftunchanged, calculate the real and reactive power output, the generated voltage and its corresponding phase angle b) Sketch the capability curve for this generator identifying the rated power, field limit curve,armature limit curve, the power angle δ and power factor angle Φ at rated conditions.
480V, 375 kVA, 0.8 lagging power factor Y - connected synchronous generator has synchronous reactance of 0.4 ohm and negligible armature resistance. This generator is supplying power to 480V 80KW 0.8 P.F leading , Y - connected S.M with synchronous reactance of 1.1 ohm and negligible armature resistance . The S.G is adjusted to have a terminal voltage of 480V when the motor is drawing the rated power at unity power factor . Calculate 1) the magnitudes and angles of emf for both machines. 2) if the flux of motors is increased by 10 percent, what happens to the terminal voltage of power system? What is its new value ? 3) what is the power factor of the motor at the new case.