ABB RELION REX640 Technical Manual page 540

Section 4
Protection functions
534
fault (Rf = 0 Ω). Another advantage of the method is that it can estimate correct current
magnitude also during intermittent or restriking faults.
The setting Min operate current defines the minimum operate current which must be
exceeded for the function to start or operate.
Setting Operating quantity defines whether the current magnitude supervision is
based on the "Adaptive", "Amplitude" or "Resistive" methods.
Table 561: Comparison of Operating quantity of MFADPSDE with traditional methods
Traditional method Setting Operating quantity of MFADPSDE
Adaptive
Iosin
Iocos
Iosin/Iocos x
When Operating quantity is set to "Adaptive", the method adapts the principle of
current magnitude supervision to the system earthing condition. This is done by
monitoring the phase angle of accumulated sum admittance phasor, (see
+90 deg.

Tilt angle
-90 deg.
GUID-88D615AB-BE90-484A-8ABD-B4AE1160A33B V1 EN
Figure 290: Automatic adaptation of current magnitude supervision condition
(setting Min operate current) to either resistive part or amplitude of
1
I based on the phase angle of accumulated sum admittance
ostab
phasor, when setting Operating quantity = "Adaptive". Directional
mode = "Forward"
Amplitude
x
+45 deg.

0 deg.


1MRS759142 C
Resistive
x
Figure 290).
REX640
Technical Manual