Question { Bhilai, 30995 }

11kv/0.433kv, 2 mva , transformer , for protection and
metering how many CT/PT are required?

Answer

3 line PT's prot./meter in 11kv side(before side)
3 prot/meter. CT's at 11kv side(before side)
3 line PT's prot./meter in .433kv side(after side)
3 prot/meter. CT's at .433kv side(afterside)
In each CTs & PTs,ther wil b a seperate core for metering n
protection,dont get confused with the windings in assuming
tat this is for ef,oc and differential,get a CT/PT wit both
metering n protection whatevr d core is depends upon our
application in relays.

Question { APTransco, 37277 }

WHERE IS THE LIGHTING ARRESTER SHOULD BE PLACED IN
DISTRIBUTION LINES?

Answer

if d primary n sec. of a transformer both r hv means ,la is
placed on both d sides,if it is a hv-lv transformr la can b
placed at hv side,these r mainly placed for power/outdoor
transformers

Question { 37612 }

In neutral the current will flow or not?

Answer

hi to all n Abc, let the system be in balanced
condition,all current path circuits gets closed at
neutral,let us consider a heater coil 1 end is connected to
phase and another to neutral, according to ur view in
neutral current flow is not there, my question is how u get
a closed path for this current? (dont compare with 3 phase
neutral/Transf. or motor)

Question { 79547 }

what is the significance of KV & MVA rating of the
transformer and how they are related.

Answer

significance of voltage n power,KV*I*1.732=MVA

Question { 79547 }

what is the significance of KV & MVA rating of the
transformer and how they are related.

Answer

if t/f power rating is 1 mva,prim volt=10kv,sec
volt=400v,,,prim current=(1mva/[1.732x10kv])=>57.7367
Amps,sec current=(1mva/[1.732x400])=>1443.4180,,,,,pls
correct it Mr.Eduardo

Question { NTPC, 23380 }

1)Why electric shock is feel ?? n in a Electric Train why
we didnt feel that ?

2)What is the reason for transformer Noise ??

3)What is relation b/w Transmission Lines & Communication
Lines ?

4)Which material is used for making Transformer oil & How u
measure its dielectric strength & Name the test ?

Answer

1.if v touch a live wire,using ur body it gets a ground so
u feel shock,in case of electric train every compartment
wheel is grounded(negative dc) so u cont get shock even if
fault occurs
2.i think its corona loss
3.trans lines used for carrying power,trans lines can also
be used as a communication line using PLCC power line
carrier communication
4.material who needs/IL335 is the indian standard oil for
tfmr oil.u can measure the dielectric strength by doing a
Break down voltage test(dielectric test for oil)

Question { NTPC, 23380 }

1)Why electric shock is feel ?? n in a Electric Train why
we didnt feel that ?

2)What is the reason for transformer Noise ??

3)What is relation b/w Transmission Lines & Communication
Lines ?

4)Which material is used for making Transformer oil & How u
measure its dielectric strength & Name the test ?

Answer

ya hi rajkumar i agree wit u its due to vibration but i had
not conformed tat the answer was correct

Question { ABB, 12529 }

During a temperature rise test of a bus duct, it is fed
with 415 volts at 2000 amperes. Why dont we get an electric
shock if we touch the bus bars?

Answer

if u ground that bus bar during testing then wat test wil u
conduct on that?if d bus bar gets 2000A v can realize a
heat but wat about tat 415V,i wil anser soon...

Question { 11710 }

what is differnt between metering CTs an protection CTs

Answer

Metering cts used only in measuring secondary currents(in
view of primary current),no knee point voltage ,winding
resistance is low.
Protection cts r used incase of any faults in d system,knee
point voltage is there,winding resis. is high.