Write the formula for Fault MVA, Fault current, Base MVA.
Answer Posted / mak
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 ? | 3 Yes | 4 No |
Post New Answer View All Answers
Why field rheostat is kept in minimum position while armature rheostat at maximum position?
plz send me the syllabus or any sample paper for engineer trainee recruitment if any,on ravinder911@yahoo.com
Why squirrel cage motor can only use with low starting loads ?
what is thresold of perception
1)How much current can a 3-1/2 core 100 mm wire carry? 2)What are the special cables required for explosion proof wiring? 3)In case you do not have coal and salt for earthing, how can you achieve good temporary earthing? 4)One horse power single phase motor is more likely to get hot than a one horse power 3 phase motor. Is it true or false, if true why? 5)What are the different types of soft starters for large motors?please explain?
List out the different frequency domain specifications?
Explain the term parallel path in dc machin ?
how to calculate the settings for shaft ct protn in hydro generators
What is the approximate value of stacking factor?
why the frequency and voltage in india is 230v and 50HZ. when compared to USA say 110v and 60 HZ.
distribution is maximum done by a)radial b)network c) parallel d)b & c
upto how much low RPM we will run the commercial motor which is run through VFD without any problem occurs in motor.Motor rating Duty is S1 & RPM is 1400.
Dear sir, my knowledge about cable size determination is limited. Though I read examples I could not calculate the Cable size required for electric driven pump 40 KW, 380 Volt, 50 HZ, 50 meter from transformer and it is three phase star delta starting. Please help as there is no one in my surroundings to help.
why we use single core 630mm2 cable for transformer secondary side
although ckt breakers have taken the place of old fuse. But instead of it , these older ones are still used in the industries and homes ? why .... what are their advantages and disadvantages ? which one is leading and winning the race and competition ?