Looking at how to test for direction earth faults using the Megger SVERKER900 relay and substation test system.
Directional earth fault protection are commonly used to protect long outgoing feeders from tripping because of fault on other outgoing lines. Because of changing from over-head lines to cables the capacitive input from outgoing feeders has increased. This makes healthy feeders trip if directional earth fault protection is not used.
Restriking fault has also increased because of isolating problem with aging cables. In this application the directional earth fault protection for outgoing feeders (Sepam S84) is used.