Interested to Buy Any Domain ? << Click Here >> for more details...
What is the harm if we install primary side 11 KV VCB at a
distance of one Km from the 11/3.3KV 12.5 MVA transformer
through 11 KV cable.
- 4 Answers
- 10156 Views
- I also Faced
- E-Mail Answers
Answer Posted / khor
No harm at all,but finding cable is a problem.11kv cable
supply for 12.5MVA must carry 650A per phase which is too
big for most standard cables.Standard VCB are 630A,1250A &
2000A,2500A.The more commonly available large size 3-core
300sqmm 11kv copper(450Amp) or alluminium conductor
cables,which is still flexible and can be transported &
coiled in drums of 250 to 300 metre lengths.There are
500sqmm 11kv 1-core xlpe/awa/pe cables available.
If you use only one transformer which is more
economical,the 3.3 KV side will be more than 2187Amp(plus
additional amp on losses and fans).While you can find 2500A
VCB,you will need more than 600sqmm copper conductors which
is not flexible/practical.
For the better/optimum design,seperate the final 415V and
3.3KV loads required and divide them into 2 groups and look
at the MVA and size them in seperate circuits.If 12.5 MVA
is all in 3.3Kv then employ 2 Main transformers where you
are not putting all the eggs in one basket.You need to
remember to look at the short circuit capacity( in KA 1 sec
or 3sec ) of the cables in circuit where small MVA is
involved.For e.g.1 MVA needs 52A @11KV but you cannot use
35sqmm cables,as it will blow like a fuse during fault
situation.
1 km of cables will have quite enough impedence to
limit/lower the fault level of the system.Protection of
this cable can be done with Pilot protection relays on
sending and rereving end,operated by class X CTs mounted in
the 11KV VCB panels.1 KM of Pilot wires of 2.5 sqmm 7-cores
alomg this cable is requird.So far I am assuming that it is
uderground cable is used.For Ariel Bundle Cable,3-core 185
sqmm aluminium is available.
| Is This Answer Correct ? | 3 Yes | 2 No |
Post New Answer View All Answers
What are the basic elements used for modeling mechanical translational system?
What is making & breaking current ???
How can we increase fuel-power ratio of any DG set?
How to calibrate or test an LT Air Circuit breaker 440 volts, 35 KA, 800 Amps ?
How one can check the MAIN of a house wiring ?
Help need in transformer !? Hello Friends The parameters of 2300/230 v 50hz t/f is R1=0.286 ohm R`2=0.319 ohm Rc=240 ohm X1=0.73 ohm X`2=0.73 ohm Xm=49.2 ohm Secondary Load impedance ZL=0.387+J0.29 solve the exact equivalent circuit with normal voltage across primery.. I know every thing but i cant find CURRENT I1=? and I`2=? Please help me give solution or only Formula please please...
difference between high and low impedance BUS BAR relay??
how we can come to know that motor winding resistance which showing by DMM is right or wrong???is there any chart or something that we will compare & check???
how to calculate cable size in diffrent loads?
Why compensation is necessary in feedback control system?
What is the function of NGR for the parallel operation of alternator? whats happen when different rating of alternator are running with parallel?
what is the differebt between ac and dc fuse?
What are the effects of electrical faults?
What is CCM in Electrical ? where can we use this material?
what is negative and zero impedance in 3 phase induction motor ??
