Three 6.6 kV altenators of ratings 8 MVA, 2 MVA and 5 MVA have per unit reactances of O.16, 0.08 and 0.12 respectively and are connected to a common bus bar. A 3-phase fault occurs on a feeder which takes off from the bus. The reactance of the feeder from the bus to the fault point is 0.125 ohm. Find the fault MVA. [87.2 MVA]

Three 6.6 kV altenators of ratings 8 MVA, 2 MVA and 5 MVA have per unit reactances of O.16, 0.08 and 0.12 respectively and are connected to a common bus bar. A 3-phase fault occurs on a feeder which takes off from the bus. The reactance of the feeder from the bus to the fault point is 0.125 ohm. Find the fault MVA. [87.2 MVA]

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...

See similar textbooks

Related questions

Q: A fault occurs at bus 4 of the network shown in Figure Q3. Pre-fault nodal voltages throughout the…

A: x=1y=7Note: reactance of element right to bus 4 is not given. Hence we will not consider that in…

Q: In a short-circuit test on a 3-pole, 220 kV circuit breaker. Power factor of the fault = 0.8…

Q: b) A fault occurs at bus 2 of the network shown in Figure Q3. Pre-fault nodal voltages throughout…

Q: Figure 2 shows the circuit of a simple power system. The ratings of the generators, transformers and…

A: As per the guidelines of Bartleby we supposed to answer 1st three subparts of the question. For…

Q: A 3 phase fault occurs at bus 1. Fault impedance Z, =j0.2 p.u. Z,, = 0.07286 p.u. Then the fault…

A: In this answer we will try to find out the fault current at bus-1 as shown below. Fault current is…

Q: 1. The subscript d in the generator subtransient reactance refers to: 1. Generator 2. Generator 3.…

A: Subtransient: It occurs extremely fast- faster than even transient. The subtransient time period…

Q: Problem 1(B)- If the fault in Problem 1(A) was a Line-Line fault between phases B and C through a…

Q: = For the power system shown below, all reactances are given to the same base 100MVA and 33 KV. A…

Q: Determine the symmetrical fault in each bus as shown in figure. Assume all pre-fault voltage to be…

A: To determine the symmetrical fault currents at each bus in the given 4-bus power system, we will…

Q: B:A 20 MVA transformer which may be called upon to operate at 30% overload, feeds 11 KV busbars…

Concept explainers

Fault Analysis

In an electrical engineering system, a fault is an abnormal electric current flowing through the system, and fault analysis is the study of these faults. For instance, a short-circuit is a fault where the live wire touches the ground or neutral wire. If a circuit is interrupted by a failure of a current-carrying wire then an open circuit fault occurs. The open-circuit faults are also called series faults. One or more phases or ground may be involved in a three-phase fault or may occur only between two phases. Current flows into the earth in case of a ground fault or earth fault. For most situations, the prospective short circuit current of a fault that is predictable can be calculated. To limit the loss of service because of a failure, the protective devices can detect fault conditions and operate circuit breakers and also other devices. All phases equally can be affected in a poly-phase system which is known as symmetric electrical fault. The asymmetric fault becomes more complicated to analyze if only some phases are affected. By using methods such as symmetrical components, the power system analysis of these types of faults is often simplified. The main objective of power system protection is to design, detect, and interrupt power system faults.

Question

100%

Three 6.6 kV altemators of ratings 8 MVA, 2 MVA and 5 MVA have per unit reactances of 0.16,
0.08 and 0.12 respectively and are connected to a common bus bar. A 3-phase fault occurs on a
feeder which takes off from the bus. The reactance of the feeder from the bus to the fault point is
0.125 ohm. Find the fault MVA.
[87.2 MVA]

Expert Solution

This question has been solved!

Explore an expertly crafted, step-by-step solution for a thorough understanding of key concepts.

SEE SOLUTION Check out a sample Q&A here

Step 1

VIEW

Step 2

VIEW

Step by step

Solved in 2 steps

SEE SOLUTION Check out a sample Q&A here

Knowledge Booster

Learn more about

Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, electrical-engineering and related others by exploring similar questions and additional content below.

Similar questions

Last time i got wrong please help me
Q.3 When a line-to-ground fault occurs, the current in faulted phase 'a' is 100A. The zero-sequence current in phase 'c' is r
Figure 2 shows the circuit of a simple power system. The ratings of the generators, transformers and the motors are as shown in the figure. The reactance of lines 1 and 2 are 40 ohms and 50 ohms respectively. Assume that system is unloaded, and the generators are generating their rated voltage. Select the generator G₁ ratings as base values. Choose the fault location in bus 3. And give the bellow answer For a symmetrical three phase fault on the bus 3 1. Calculate the fault current in ampere and fault power in MVA and the fault current contribution from the generator connected to the bus 3.
B:A 20 MVA transformer which may be called upon to operate at 30% overload, feeds 11 KV busbars through a circuit breaker: other circuit breakers supply outgoing feeders. The transformer circuit breaker is equipped with L000/5 A CTs and the feeder circuit breakers with 400/5 A CTs and all sets of CTs feed induction type over current relays. The relays on the feeder circuits breakers have a 125% plug setting, and 0.3 time setting. If 3 ph fault current of 5000 A flows from the transformer to one of the feeders, find the operating time of the feeder relay, the minimum plug setting of the transformer relay and its time setting assuming a discrimination time margin of 0.5 sec. Relays having the following characteristics for TMS-1 PSM T in sec. 2 3.6 5 10 15 20 10 6 3.9 2.8 2.2 2.1
19
Describe the process of fault current analysis in power systems and its significance in protecting electrical equipment from damage.
If an unsymmetrical fault occurs on phase C of a transmission line, what would make the fault symmetrical? A. if phase C of the transmission line opens B. If phases A and B become faulted C. If two different faults occur on phas a and b
If the source impedance at a 13.2 kV distribution substation bus is (0:5 + 1:5) Q per phase, compute the RMS and maximum peak instantaneous value of the fault current, for a balanced three-phase fault. For the system (X/R) ratio of 3.0, the asymmetrical factor is 1.9495 and the time of peak is 7.1 ms (see Problem 1). Comment on the withstanding peak current capability to which all substation electrical equipment need to be designed. Problem 1 Consider the expression for i(f) given by i(t) = v21ms [sin(@t-0-)+ sin 0,.eR/X)] where ez = tan-1 (WL/R). (a) For (X/R) equal to zero and infinity, plot i(f) as a function of (wf). (b) Comment on the DC offset of the fault current waveforms. (c) Find the asymmetrical current factor and the time of peak, tp, in milliseconds, for (X/R) ratios of zero and infinity.