Answer / thowsif_emerson_csm team

The CT Will Burn....

Why does opening a CT's secondary cause dangerously high
secondary voltage?
With the flow of both primary and secondary currents the
transformer's exciting current is very low. The secondary
current mmf serves to keep the magnetizing flux in check!
If the secondary now opens the primary current mmf produces
an exciting current 'orders of magnitude' greater than
normal. And, the resultant large increase in flux density
produces an extremely high voltage in the secondary.

Regards,
Thowsif.

Answer / mohankumar n , aee power plant

since I1/I2=V2/V1= K which is called as transformation
ratio if CT secondary gets openned A High voltage across
secondary will results on over heating of ct & if it is
allowed results on ct flashover. CT openned secondary
voltage depends on the line voltage & ratio. ie IF line
voltage is 415v & ct ratio is 1000/1 Amps during secondary
opennned case voltage will be 415*1000=415000 volts. this
voltage will definetly damage the ct as its insulation
level is lower than yhis.

Answer / b.murali dhara babu

The Current transformer cores used for protection are
designed to work at low flx density during normal operating
conditions i.e at rated capacity .During the CT secondary
open conditions the flux produced in the core will become
high due to flow of current in the primary and has no
oppsing flux due to CT secondary winding . This may
causes development of the high voltage which is equal to
E=4.44 x flux x Frequency .Diring the fault conditions the
current value goes up and there by the flux value in the
core also goes up and causes very high voltage to develop
in the CT secondary . The CT secondary insulation was not
suffient to with stand the voltge stress and causes the
filure of insulation and inturn the CT .

Answer / ritesh khimani

i think the net power that can be transfered by ct is the
diffrence between primary and secondary power.if seconbary
is made open then net power becomes primary power which may
cause the damage to the transformer.

Answer / mahesh

suppose secondary circit is open the ct is failed.we have to now ct is consist of primary and secondary windigs if secondary is opene large amount of current is flow and damage of ct.

Answer / ramaswamy

transformer failed

Answer / pushpa.m.j

Transformer is used to transmit the higher power in to
required amount that is from primary circuit to secondary
circuit .If secondary circuit opens means there is no any
current,hence transfermer is failed to transform the power.

Answer / santhosh

its depend on the windings if secondary more no winding
compare to primary then it do not effect it

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