A new high-speed balanced-current relay

NEED for a high-speed, balanced-relay current which will not function when the first half-cycle current is deficient in one of the two parallel circuits being protected, has been shown by the recent paper “The Effect of Current-Transformer Residual Magnetism on Balanced Current or Differential Relays.”¹ This is the result of high residual magnetism of the current transformer caused principally by the d-c component of an offset wave on previous short circuits.