Interested to Buy Any Domain ? << Click Here >> for more details...
Answer Posted / ramesh kumar k
CT & PTs are called as INSTRUMENT TRANSFORMERS as these are
used to measure Currents (CT) and Voltages (PT it is also
called as VT) in circuit mainly in HT lines.
There are nothing but Ammeter/Voltmeters. But the
difference is... Ammeter/Voltmeter are used to measure the
quantities (Current/Voltage) in a 220V line or house hold
applications as these instruments are insulated upto that
level only.
But how to measure the I or V in High Voltage Lines...
there CTs/VTs are used... These have mainly 2 advantages...
There are Primary & Secondary coils in CTs/VTs as in case
of a normal transformer...
1. These Ammeter/Voltmeters can't be used there....
because they are insulated for 230V only (or 3kV at
most)... in we connect these in HT lines... they will burn
out and also dangerous to the persons who are handling
these instruments... So these will give the I or V values
at a reduced voltage levels...
2. As the I or V in the HT lines are heavy... (i.e upto
some thousands of Amps/Volts) we can't manufacture the
general Ammeters/Voltmeters upto that level.. as it makes
costlier.. so we reduce the line values to a measurable
limits (i.e. 5A or 1A or 110V or 100V) by using Induction
principle.
we connect the primary to HT lines and we will get the I or
V at the secondary with a reduced current/voltage level...
so we can connect our normal Ammeters/Voltmeters directly
to measure the I or V in HT Lines...
Ex.:
A CT of 200/1A shows that.. if ammeter connected in
Secondary of a CT indicates 1A that means there 200A is
flowing in the Primary of CT (i.e. in HT line)
in a 132kV / 110V VT, if voltmeter in the secondary of a VT
indicates 110V that means there is 132kV in the primary.
And then these can be used for different purposes like
metering, Protection, Special Protection etc..
| Is This Answer Correct ? | 155 Yes | 3 No |
Post New Answer View All Answers
How To Convert Apparent Into Real Power Without Knowing Reactive Power?
what is the generator rating for 40 amp load of 3phase motor.?? 400v voltage of generator... plz tell me with formula its urgent...plzzz... and also tell me that this 40 amp at all phases mean 40 amp on red,40 amp on yellow,40 amp on blue...... or the total sum of that 3phase is 40 amp....
WHAT IS MEANT BY TV TERMINAL IN 500MVA TRANSFORMER?
can anyone explain the star-delta motor control wiring ,which wire go where and how they operate?
What is difference between isolator and circuit breaker?
How wire size can define in electrical wiring? What is the ratio?
ELECTRICAL DRIVES: can a motor load system with passive load torque can have equilibrium speed in second quadrant
Sir, I have applied for the of Jr.engineer(Electrical & Electronics) & ASST. LOCO PILOT at ALL RRB BOARDS. please send me all RRB Boards solved papers in the year of 2001 tO till date. i requested send me the papers to my id as soon as possible (jet_0991@yahoo.com). (This is very urgent) Thank You,
what is relation between ct and pt ratio with multiplication factor of a energy meter? is there any other factor on which multification factor depend?
HOW TO CALCULATE EARTHING SIZING?
Disadventage of cable-gland earthing if any ?
What is excitation in case of dc motor?
How we select the vector group of 3phase power transformer?
what is PID control in VFD drives?
how to carried out tan delta test in 11 KV alternator ?
