Why core balance CT is preferred over residual connected CT’s to sen

1.	Why core balance CT is preferred over residual connected CT’s to sense earth fault in 6.6 kV feeders?
Answer» a) To avoid relay mal-operation due to CT saturation b) Better sensitivity is got. c) High pickup and TMS avoided in IDMT earth fault relay.

Why core balance CT is preferred over residual connected CT’s to sense earth fault in 6.6 kV feeders?

Answer»

a) To avoid relay mal-operation due to CT saturation

b) Better sensitivity is got.

c) High pickup and TMS avoided in IDMT earth fault relay.