Relays

by Roberto Cimadevilla and Javier Garcia-Villalobos, ZIV, Spain

The use of line differential protection has been spreading more and more due to the increased availability of communication channels with adequate bandwidth. Line differential protection provides important advantages over distance protection such as better resistive coverage; good dependability for cross-country faults, selectivity protecting short lines, unaffected by: power swings, voltage inversions in series compensated lines, mutual coupling in parallel lines, load encroachment, etc. However, line differential relays may be affected by several adverse conditions such as severe CT saturation, SDH switching, very high resistive faults, high capacitive current, communication errors. More

Power. Flexible. Easergy.
BeijingSifang June 2016