ALLInterview.com :: Home Page            
 Advertise your Business Here     
Browse  |   Placement Papers  |   Company  |   Code Snippets  |   Certifications  |   Visa Questions
Post Question  |   Post Answer  |   My Panel  |   Search  |   Articles  |   Topics  |   ERRORS new
   Refer this Site  Refer This Site to Your Friends  Site Map  Bookmark this Site  Set it as your HomePage  Contact Us     Login  |  Sign Up                      
Google
   
 
Categories >> Engineering >> Electrical Engineering
 
 


 

 
 Civil Engineering interview questions  Civil Engineering Interview Questions (3073)
 Mechanical Engineering interview questions  Mechanical Engineering Interview Questions (3287)
 Electrical Engineering interview questions  Electrical Engineering Interview Questions (13323)
 Electronics Communications interview questions  Electronics Communications Interview Questions (2364)
 Chemical Engineering interview questions  Chemical Engineering Interview Questions (416)
 Aeronautical Engineering interview questions  Aeronautical Engineering Interview Questions (77)
 Bio Engineering interview questions  Bio Engineering Interview Questions (17)
 Metallurgy interview questions  Metallurgy Interview Questions (79)
 Industrial Engineering interview questions  Industrial Engineering Interview Questions (163)
 Instrumentation interview questions  Instrumentation Interview Questions (2375)
 Automobile Engineering interview questions  Automobile Engineering Interview Questions (106)
 Mechatronics Engineering interview questions  Mechatronics Engineering Interview Questions (38)
 Marine Engineering interview questions  Marine Engineering Interview Questions (43)
 Power Plant Engineering interview questions  Power Plant Engineering Interview Questions (75)
 Engineering AllOther interview questions  Engineering AllOther Interview Questions (1196)
Question
Write the formula for Fault MVA, Fault current,  Base MVA.
 Question Submitted By :: Electrical-Engineering
I also faced this Question!!     Answer Posted By  
 
Answer
# 1
- Draw the per phase diagram of the system
- Express all impedance in per unit values
- Choose a common MVA base and express all Zpu on the
selected common MVA base

Znew= Zpu(MVA base/ MVA)
-Calculate the total per unit impedance of the system
using circuit principle
- Calculate the fault power
MVA fault= MVA base/ Z total per unit

I fault = MVA fault/ 1.73* V
 
Is This Answer Correct ?    8 Yes 4 No
Ariel
 
Answer
# 2
The fault current of a power transformer will depend on the following;
Transformer Rating (in KVA/MVA)
per unit impedence of the transformer (%p.u.)
line/phase Voltage (VL/VP)
the following formula can be used to find the fault current on the secondary side of a transformer
Fault Current = Transformer Rating /(per unit impedance x phase voltage)

The Values of Transformer Rating, per unit impedance & phase/line voltage will usually be mentioned on the transformer rating plate / data sheet
As an example a 500kVA, 11kV/400V/3-Phase/50Hz transformer with 5% p.u impendence will have the following fault levels on the secondary side

Fault level = 500/(5%)=10000kVA


Fault current = 500/(5% x 400 x 1.732) = 14.4 kA

Remember to use 3phase voltage!
 
Is This Answer Correct ?    1 Yes 0 No
Mak
 
 
 

 
 
 
Other Electrical Engineering Interview Questions
 
  Question Asked @ Answers
 
working principle of induction motor is similar to transformer. but what makes it to rotate? then why the transformer doesnt?   4
What is the technical reason for adopting color coding of three phase system as RYB. ABB 10
what is the relationship between induction motor and transformers? Reliance 8
The unit of electrical charge is the   1
what happens when one of the phases out 0f 3 phases been removed under working condition and no load condition will the machine run if so plz send me why   2
Why the CT Secondary is rated as 5A generally?   2
In the solution of load flow eqation, Newton raphson method is superior to the gauss siedal method because (a)the time taken to perform one iteration in the NR method is less when compared to GS method (b)the number of iterations required in the NR method is more compared to that in the GS method (c)the number of iterations required is dependant on the size of the system in the NR method (d)convergence characteristics of the NR mehod are not affected by the selection of the slack bus   1
I want to wire sizing calculator which website is available it   1
Why fuel tanks to be earthed ? HPCL 6
what is the differance beetwen installation and errection ?   1
what is significance of B-H curve? how it differs form ordinary transformers to Amorphous Transformer? BARC 1
In a 11000/440 V transformer, when any one phase of 11 KV supply fails (ie., single phasing), what happens to the secondary voltage and why? Secure-Meters 3
 
For more Electrical Engineering Interview Questions Click Here 
 
 
 
 
 


   
Copyright Policy  |  Terms of Service  |  Articles  |  Site Map  |  RSS Site Map  |  Contact Us
   
Copyright 2013  ALLInterview.com.  All Rights Reserved.

ALLInterview.com   ::  KalAajKal.com