ABB RELION REX640 Technical Manual page 578

Protection functions
Figure 333: Activation of BLK_EF output (indication that fault is located opposite to
the set operate direction)
4.2.9.6 Application
MFADPSDE provides selective directional earth-fault protection for high-impedance
earthed networks, that is, for compensated, unearthed and high-resistance earthed
systems. It can be applied for the earth-fault protection of overhead lines and
underground cables, regardless of the earth-fault type (continuous, transient or
intermittent) or the fault resistance value (low or high ohmic). MFADPSDE replaces
traditional sensitive directional earth-fault protection (such as Iocos) and transient
earth-fault protection (such as Wischer principle) combining the same functionality
into a single function block (see
578
Table 616
).
1MRS759142 F
REX640
Technical Manual