ABB RELION REX640 Technical Manual page 556

Section 4
Protection functions
550
sequence voltage falls below Voltage start value. BLK_EF is reset once the reset delay
time elapses. Activation of the BLOCK input deactivates the BLK_EF output and
resets Timer.
BLK_EF output is activated when the following conditions are met:
• Earth fault is detected by the GFC.
• Fault direction is opposite to Directional mode setting.
The estimated stabilized fundamental frequency residual current
internally fixed threshold, which is 1% of In. This current magnitude threshold
supervision is based on the "Amplitude" method.
GUID-A2AA5DB2-5589-47CD-89AA-10788020B3E5 V1 EN
Figure 300: Activation of BLK_EF output (indication that the fault is located
opposite the set operate direction)
1MRS759142 C
1
I
exceeds the
o stab
REX640
Technical Manual