:: 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                      
Categories >> Engineering >> Electrical Engineering


 Civil Engineering interview questions  Civil Engineering Interview Questions (3151)
 Mechanical Engineering interview questions  Mechanical Engineering Interview Questions (3304)
 Electrical Engineering interview questions  Electrical Engineering Interview Questions (13475)
 Electronics Communications interview questions  Electronics Communications Interview Questions (2394)
 Chemical Engineering interview questions  Chemical Engineering Interview Questions (423)
 Aeronautical Engineering interview questions  Aeronautical Engineering Interview Questions (77)
 Bio Engineering interview questions  Bio Engineering Interview Questions (17)
 Metallurgy interview questions  Metallurgy Interview Questions (80)
 Industrial Engineering interview questions  Industrial Engineering Interview Questions (166)
 Instrumentation interview questions  Instrumentation Interview Questions (2407)
 Automobile Engineering interview questions  Automobile Engineering Interview Questions (108)
 Mechatronics Engineering interview questions  Mechatronics Engineering Interview Questions (38)
 Marine Engineering interview questions  Marine Engineering Interview Questions (45)
 Power Plant Engineering interview questions  Power Plant Engineering Interview Questions (81)
 Engineering AllOther interview questions  Engineering AllOther Interview Questions (1205)
How to calculate HT XLPE CABLE for 11 kv / 433 v , 1500 kva
oil type transformer system?
plz provide step by step calculation
 Question Submitted By :: Electrical-Engineering
I also faced this Question!!     Answer Posted By  
# 1
3core-185 sq. mm


Current at HT = (1500 x 1.4)/ (33*1.732)
Is This Answer Correct ?    143 Yes 84 No
Divay Chadha
# 2
Generally HT cable sizing is not done based on the full
load current of the equipment but based on the prospective
fault level. For a 11kV network, generally it shall not be
less than 150sqmm XLPE.

Fault level at 11kV(furnished by respective EB)=100 MVA(say)

Details on EB's fault level can be obtained from EB.

Therefore fault current= 100*1000/(SQRT(3)*11000)
= 5.25 kA

Short circuit current rating (for 3-sec duration)of HT 11kV
XLPE cables with Alu conductor is as below:
95 sqmm: 5.16 kA
120 sqmm: 6.51 kA
150 sqmm: 8.14 kA
Is This Answer Correct ?    67 Yes 16 No
# 3
please slect your cable in 11kv py side how much current
check first after you slect your ht cable.
Is This Answer Correct ?    64 Yes 29 No
# 4
simple for 11kv
Amp in HT= kva*1000/ 1.732*11000

= size for 78 amp HT XLPE 3 core 95 mm2 higher side.
Is This Answer Correct ?    57 Yes 28 No
Neeraj Tyagi
# 5
11kv----13 amps on primary side

1500 kva 1.4 = 2100 amps on secondary
Is This Answer Correct ?    29 Yes 14 No
# 6
First calculate the current of primary side(HT) and derate the cable by atleast 0.7.
Current I after Derating =78.73/.7 =112A (0.7 if laid on the trays or value will vary if buried in the ground).
Cable equivalent to rating has to be selected.
Now Short circuit withstand capacity (sq. of I X t in sec) has to be checked from the cable catalogue.This value of cable should be higher then SC withstand capacity of the ground usually it is less go for next size and finalise.
Is This Answer Correct ?    19 Yes 13 No
Madhu Mohan
# 7
1500kVA X 0.8 PF = 1200Kw = 1200000W

P=RT3 V I COS fi

I = -----------
RT3 x V x COSfi

I = -----------------

= 79 A

Now take cable table and select the suitable xlpe cable.

Is This Answer Correct ?    33 Yes 29 No
# 8
HT Cable select, its depend of incoming capacity of feeder
line. say feeder capacity 100 MVA SO Calculate current I=
100*100/11*1.73=5.25kA. So we can select of HT Cable for
minimum short ckt current carrying capacity of minimum 5.2kA.
Is This Answer Correct ?    1 Yes 1 No
# 9
90 Al Ar XLPE cable is sufficient. But as per statutory norms for 11kV, 185 Cable is considered. 
Is This Answer Correct ?    1 Yes 1 No
# 10
Assume PF of transformer is .8.
rating of transformer=1500kVA=1500X.8=1200kW
So that maximum current-
So cable size required if copper cable
1mm=4amp= 400sqmm(by consedering all factors)
For aluminium cable
Is This Answer Correct ?    57 Yes 90 No
Govind Bisht

Other Electrical Engineering Interview Questions
  Question Asked @ Answers
i need to calulate the cable size when watts are mentaind wat z the formula   1
11kv alternator commissioning test?   2
Please tell me ceilingfan sweep means. Commenly we used sweep1200mm and 600mm MMENLY WE USED CEILINGFAN SWEEP1200MM AND SWEEP600MM   1
how to convert psi into kilo pascal? what is the suction pressure & discharge pressure of chiller?   1
What is the make of breakers, transformers, generators? What are their capacities and ratings? Bharat-Bijlee 2
what is meant by impedance testing of transformer and why it is used TATA 1
the relationship between phase and line voltages in a 3 phase generator is expressed in what formula? Omicon 4
will three phase energy meter run without one phase   2
How much Fault current can be contributed by a motor?   4
Can someone help me in the Below Quest on Earthing 1.Types of Earthing and Recommended for what use 2.What is the Pit value /Panel N -E value should be or within limit for RP and UPS .   1
how many amps in 1 KVA? V=440v, PF=0.8 and FREQ=50Hz   22
why transformer ratings in kva? Bhel 93
For more Electrical Engineering Interview Questions Click Here 

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