Sensitive Earth Fault (SEF) Protection of Transformer || Standby Earth Fault (SEF) Protection

[@ramanjain1313]

This is the circuit is for REF ? Why calling it by SEF?

[@Technicalguy_123]

Ref is operating for external fault even though stability test is correct what could be the issue

[@360Engineer01]

Are you using 4 CT or 5 CT ?
If 4 CT, check for Neutral CT Location

[@sanjaykashikar940]

In this video the neutral polarity is wrong, it should be reverse. In healthy condition no issue but it will operate for external earth fault and will not operate on internal fault.

[@360Engineer01]

In this video only SEF protection explained and overlooked the polarity of REF

[@360Engineer01]

4CT or 5CT configuration?

[@Technicalguy_123]

@@360Engineer01 4CT