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, X¼ = 0.3, Xa = 1.4(pu) and its time constants are Tä = 0.05, T = = 1.0, T, = 0.1(s). The transformer series reactance is 0.06pu; transformer losses and %3D 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 (d) The RMS ac (symmetric) fault current (kA) after 3 cycles (e) The RMS asymmetrical fault current the breaker interrupts (p.u.), assuming maximum dc offset (f) The RMS asymmetrical fault current the breaker interrupts (kA) assuming maximum dc offset

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, X¼ = 0.3, Xa = 1.4(pu) and its time constants are Tä = 0.05, T = = 1.0, T, = 0.1(s). The transformer series reactance is 0.06pu; transformer losses and %3D 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 (d) The RMS ac (symmetric) fault current (kA) after 3 cycles (e) The RMS asymmetrical fault current the breaker interrupts (p.u.), assuming maximum dc offset (f) The RMS asymmetrical fault current the breaker interrupts (kA) assuming maximum dc offset

Introductory Circuit Analysis (13th Edition)

13th Edition

ISBN:9780133923605

Author:Robert L. Boylestad

Publisher:Robert L. Boylestad

Chapter1: Introduction

Section: Chapter Questions

Problem 1P: Visit your local library (at school or home) and describe the extent to which it provides literature...

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