Why CT secondary should not be kept open?

Answer Posted / ashok bhatnagar

CTs are used for the measurement of high currents as a
primary sensor. The output of the CT is normally connected
to the relevant ammeter which has very low impendence and
secondary remains almost short circuited. The secondary
current has no control over primary current in a CT. If
secondary is open circuited two things will happen :
1. Due to absence of secondary current no counter magnetic
field is produced and flux in core of CT rises to
saturation level which can change the charateristics of CT
and damage it permanently
2. since number of turns in secondary is very high (1:
1000) for , a very high voltage may be induced in secondary
that can harm the prsons working on the instruments panel.

Is This Answer Correct ?    308 Yes 27 No



Post New Answer       View All Answers


Please Help Members By Posting Answers For Below Questions

Can I use distributon class/transmission class Lightning arresots for protecting the building? If not why please explain?

1431




1909


What is the cut-off rate?

723


what is mean by kneepoint voltage? when it will happen? ( my doubt is, if CT secondary is open means ct get saturation or blas? what are factors are required for calculations? plz give currect anws:

1535


How you calculate the repturing capacity of a HRC fuse

2110






how can we find thae value of capacitor for single phase motor. what is difference between starting capacitor and running capacitor.

1890


There are different classes of protections in power plants.class a,b,c are clear..is there any class d and e r there..and elaborate class b protection.

1636


Best way to measure the Soil resistance of rocky soil, three probe method and four probe method

1458


Can any answer me ,What will be the range of C.T coil for L&T energy meter EM301 used for 180 kva DG set

1783


xpression 'document.FrmQF.myemail' [

1597


what is the meaning of neutral displacement ???

2261


What difference between ref protection and differential protection ?

1341


What are the three constants associated with a steady state error?

727


take 100kva DTR( delta/wye ), what ll happen if we connect 11kv to LT side instead of connecting to HT side? will the DTR behave as a step up transformer or something else????

1819


How will polarity test of Dy5 Transformer ?

1796