hoW to select a CT?
Answers were Sorted based on User's Feedback
Answer / venkat iyer
Selection of CTs depends upon its usage, whether for
metering or protection. Class of accuracy, VA burden and
palatability to instrument safety factors need to be
considered incase of metering CTs. In case of protection
CTs, linearity factor w.r.t its primary current and
accuracy factors need to be considered. Metering CTs are
expressed in terms of Class 1 or Class 3 where as
protection cts are expressed as 5P10 or 5P15 or 5P20 or
10P10 etc. The first digit stands for the class of accuracy
and P stands for protection and the last two digits stands
for linearity.
Is This Answer Correct ? | 44 Yes | 0 No |
Answer / mervin
A CT used for Instrumentation is required to be accurate
over a normal working range , whereas CT for protection is
required to five a correct CT ratio several times the rated
current . Cores made using Nicel-Iron alloy gives accuracy
upto 5 times the rated current n suitable for
Instrumentation . Cores made using Cold rolled silicon
steel are accurate upto 15 times the rated current and
suitable for protection .An accuracy of about 2-3% is
desirable for distance and differential relays .CT burden
and CT linearity should also be considered during selection
of a CT .
Is This Answer Correct ? | 3 Yes | 0 No |
Answer / ramakrishna m
The selection of CT depends on the current ratings of relays
those are used in the protecting circuitry and also depends
on accuracy that circuitry requires.
Is This Answer Correct ? | 10 Yes | 8 No |
Answer / kapil
it depends on the protection circuitary ratings and the
accuracy u desire for the application. it must supply the
rated current to the relays with the accuracy u desire for
ur purpose,and also copper losses in the CTs should be
minimum so it also depends on the laminations and conductor
material u choose.
Is This Answer Correct ? | 3 Yes | 8 No |
advantage of cu cable over al cable
why the motor is rated as kw& transformer as kva
What is meant by harmonic distortion?
I had attend the ITC (Indian Tobacco Company) interview (For Electrical maintanance).There they was conducted me a written test.And I was passed in that.Now They are going to conduct a Practical Interview in next round.Please help me what practical test they will ask............?
What's the difference between non break power supply and non break non short break power supply
Why Parallel operation of two Transformer are Required?
What is the function of stater in tube light circuit?
Hello every one I am currently working in IT side but i have an offer to work under 'A' license holder and he says i can get c license what is the use of c license and what shall i do after getting it basically i am an electrical graduate please help me shall i leave this it job and work in electrical maintenance will i have a good future i am confused Thank You in Advance
what difference between tapping -15% to +5 % and -5% to +15% tap. & how can define HV turns on maximun & minimum tap of power transformer.
electical engg basic question
why motor run slow speed in star connection?explain how?
How will you calaculate the Ct ratio based on connected load 500KVA,and 11KV supply ?