Answer / nishad

See, Battery chargers are mainly useing for charging the
battery bank which is responsible for all control supply of
control systems such as breaker clossing coil, trip
coil,indications, protection relays, Annociators etc....
Mainly, If we are taking the supply from main, ( with
out battery back up)at the time of power failer /
breakdown how will record/ reccongnise the problem.
Secondly, Normaly we are using DC power for control.(
AC also using) for desired DC back up we can store the
supply in Battery. But inthe cause of AC how it
possible!!!!!
Moreover, in the cause control system, DC is more
efficient than AC

well, if any body can give another good answer, Most
welcome to Him. Because Knowledge is Power.....

Answer / komyozaw

Back up protection for power system.
Because when the main supply is failure and recover.
We do not know the recover voltage is Higher or lower than normal .So we should check and protect with protection relays.
this protection relays is power by battery charger.
Also all the system is shut down , the battery backup protection is remain.

Answer / trwer

See, Battery chargers are mainly useing for charging the
battery bank which is responsible for all control supply of
control systems such as breaker clossing coil, trip
coil,indications, protection relays, Annociators etc....
Mainly, If we are taking the supply from main, ( with
out battery back up)at the time of power failer /
breakdown how will record/ reccongnise the problem.
Secondly, Normaly we are using DC power for control.(
AC also using) for desired DC back up we can store the
supply in Battery. But inthe cause of AC how it
possible!!!!!
Moreover, in the cause control system, DC is more
efficient than AC

well, if any body can give another good answer, Most
welcome to Him. Because Knowledge is Power.....

Answer / sudhi.m.m.

i could partially agree with 1st and 2nd anrs, but having a doubt that cant we use relays, protecting system etc which works in ac, a substation will always maintain a supply by back feeding from other substation at the time of station shutdown, then why we are going for dc it self

Answer / kyu kyu win

1 ) to supply the stable Voltage output
2 ) to standby or backup protection .
Like mother look after her child
Mother = Battery Charger , Child = the whole control,
Metering and Backup
3 ) AC have frequency problem ( changes )
4 ) DC have not.

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