Problem 3: An alternator and a synchronous mo- tor each rated for 80 MVA, having sub-transient reactance of 25% are connected through a trans- mission line of reactance 10% on the base of ma- chine rating. The motor acts as a load of 50 MW at 0.8 pf leading and terminal voltage 15 kV when a three phase fault takes place at the motor termi- nals. Determine the sub-transient current in the al- ternator, motor and the fault

Problem 3: An alternator and a synchronous mo- tor each rated for 80 MVA, having sub-transient reactance of 25% are connected through a trans- mission line of reactance 10% on the base of ma- chine rating. The motor acts as a load of 50 MW at 0.8 pf leading and terminal voltage 15 kV when a three phase fault takes place at the motor termi- nals. Determine the sub-transient current in the al- ternator, motor and the 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

Chapter7: Symmetrical Faults

Section: Chapter Questions

Problem 7.3MCQ: The amplitude of the sinusoidal symmetrical ac component of the three-phase short-circuit current of...

See similar textbooks

Similar questions

500MVA, 21KV, star connected, 3ph 50Hz synchronous generator is operating at the rated voltage, a 3ph fault occurs at its terminal. Its reactance in p.u. are 1.5 of synchronous, 0.5 of transient, 0.2 of sub transient. The transient time is 500ms and the sub transient time is 35ms. 1. What will the AC component be after 1.5 cycles?
What is the difference between OLTC and transformers
The reactance’s of the alternator during the periods of the subtransient, transient and steady state periods are following, Leakage reactance(XL)=0.13 ohm, Damper winding reactance(XD)= 0.27 ohm Field winding reactance(Xf)=0.54 ohm and Armature reactance (Xm)= 0.73 ohm. The value of the transient reactance during the transient conditions is Transient Reactance
The reactance's of the alternator during the periods of steady state are given bellow, Leakage reactance(X)=0.18 ohm, and armature reactance (Xad) = 0.67 ohm. The value of the syncronous reactance during the steay state conditions is Syncronous Reactance in ohm
The reactance’s of the alternator during the periods of the subtransient, transient and steady state periods are following, Leakage reactance(XL)=0.16 ohm, Damper winding reactance(XD)= 0.28 ohm Field winding reactance(Xf)=0.41 ohm and Armature reactance (Xm)= 0.74 ohm. The value of the steady state reactance during the steady state condition is Steady state Reactance Answer
Problem 2 - A 1000 – MVA, 20 – kV, 60 – Hzthree-phase generator is connected through a 1000 – MVA, 20 – kVA/345 – kVYtransformer to a 345 – kVcircuit breaker and a 345 – kVtransmission line. The generator reactances are X = 0.15, Xa = 0.3, Xa = 1.4(pu) and its time constants are Ta = 0.05, Ta = 1.0, TA = 0.1(s). The transformer series reactance is 0.06pu; transformer losses and exciting currents are neglected. A three-phase bolted fault (solid 3-phase phase short circuit) occurs on the line side of the circuit breaker when the generator is operated at rated terminal voltage and at no-load. The breaker interrupts the fault 3 cycles after fault inception (neglect the effect of the transformer on generator time constants.) Determine the following (a) The subtransient current (p.u.) through the breaker (b) The sub-transient current (kA) through the breaker (c) The RMS ac (symmetric) fault current (p.u.) after 3 cycles
6. A 3 phase fault occurs at point F as shown in figure. Determine the critical clearing anglefor the system. The generator is delivering 1.0 p.u power under prefault conditio
In differential compound DC Generator the shunt field current and the series field current are in opposite direction Select one: True False For lap and wave wound generators the generated power is same. Select one: True False
The reactance of the synchronous generator after sometime of the fault cleared is ............
why is there a phase shift in rc cct?how do we make it exactily 90 degree?
SYNCHRONOUS GENERATOR A 13.8 kV, 50-MVA, 0.9 p.f., 60 Hz, four pole, Y-connected synchronous generator has a synchronous reactance of 2.5 ohms, and an armature resistance of 0.2 ohm. At 60 Hz, its friction and windage losses are 1 MW, and its core losses are 1.5 MW. The field circuit has a dc voltage of 120 V, and the maximum field current is 5A. The current of the field circuit is adjustable over the range from 0 to 10 A. The OCC of this generator is shown in the figure.
EXPLAIN THE THREE-PHASE GENERATED EMF PRODUCED BY SYNCHRONOUSALTERNATOR.