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 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.

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

Chapter8: Symmetrical Components

Section: Chapter Questions

Problem 8.32P

See similar textbooks

Similar questions

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.
For Problem 3.18, the motor operates at full load, at 0.8 power factor leading, and at a terminal voltage of 10.45 kV. Determine (a) the voltage at bus 1, which is the generator bus, and (b) the generator and motor internal EMFs.
Consider the oneline diagram shown in Figure 3.40. The three-phase transformer bank is made up of three identical single-phase transformers, each specified by X1=0.24 (on the low-voltage side), negligible resistance and magnetizing current, and turns ratio =N2/N1=10. The transformer bank is delivering 100 MW at 0.8 p.f. lagging to a substation bus whose voltage is 230 kV. (a) Determine the primary current magnitude, primary voltage (line-to-line) magnitude, and the three-phase complex power supplied by the generator. Choose the line-to-neutral voltage at the bus, Va as the reference Account for the phase shift, and assume positive-sequence operation. (b) Find the phase shift between the primary and secondary voltages.
Three-phase, 60-Hz synchronous generator is connected through a transformer and paralleltransmission lines to an infinite bus. All reactances are given in per-unit on a common systembase. If the infinite bus receives 1.0 per unit real power at 0.95 p.f. lagging, determinea) the internal voltage of the generator andb) the equation for the electrical power delivered by the generator versus its power angle δ.
Determine the per unit impedance of a three-phase generator rated at 900 KVA and 33 KV, given that its armature resistance and synchronous reactance are 40 Ohms per phase and 140 Ohms per phase, respectively.
Question 1: Figure 1 shows a single-line diagram of a three-phase, 60-Hz synchronous generator, connected through a transformer and parallel transmission lines to an infinite bus. All reactances are given in per-unit on a common system base. If the infinite bus receives 1.0 per unit real power at 0.95 p.f. lagging, determine (a) the internal voltage of the generator and (b) the equation for the electrical power delivered by the generator versus its power angle δ.
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 single-phase, 10-kVA, 200-V, generator has an internal impedance Z, of 2 Q. Using the ratings of the generator as base values, determine the generated per-unit voltage that is required to produce full-load current under the short-circuit condition.
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.
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 (500 MW) generator is delivering (180 MW) to infinite bus through the unit transformer and double transmission lines. The per-unit ractances for a given system are shown in figure below andall the reactances are based on (100 MW) base. The generator emf is ( 1.35p .u.). Determine whether the system remains stable after one circuit of the lines is switch off?
A three-phase, 100-MVA, 20-kV generator is connected to a three-phase, 100-MVA, 20-kV motor through a transmission line. The reactances of the generator and motor are 0.25 and 0.20 per unit, respectively. The line reactance is 0.10 per unit. The motor is taking 50 [MW] at 0.8 power factor leading at rated voltage. Suppose a three-phase short circuit occurs at the generator terminals, determine the transient currents in the generator and motor as well as the short-circuit current.