Answer / nithi

when SEC of the CT open circuited,
1.high-voltage buil-up in the sec side
2.core saturation-over heat-result in fire(if
prolonged).
these things will not happen in ordinary
transformer.because,
PRIMARY CURRENT IS REFLECTION OF SECONDARY
CURRENT.SO,WHEN THERE IS NO CURRENT IN sec SIDE,ONLY NO-
LOAD CURRENT WILL FLOW IN PY WINDING.BUT IN CASE OF CT,PY
CURRENT IS INDEPENDENT.SO,IF SEC OPENED,NO DE-MAGNETISING
EFFECT &FORCED TO OVERFLUXING CONDITION.

Answer / pritam upadhyay nit p

when secondary is open there ic no flux due to secondary
current to oppose flux due to primary so due to high flux
there is very high voltage induced on secondary side which
causes sparking and damage of core due to high flux demsity.
in case of power transformer flux is constant whtheer
primary open or not so there is no such case as in ct..

Answer / bhatt

If secondary of CT is opened and as we know that primary
always flow the current and by transformaton action
secondary must flow the current but in our case secondary
is opened hence Extra high voltage is induced in terminals
of secondary which can be fatal.
In case of ordinary transformer if secondary is open
primary flows only no load current hence secondary voltage
is only rated secondary votage which is not as danger as in
the case of CT.

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