ABB RELION REX640 Technical Manual page 564

Protection functions
Table 615: Comparison of Operating quantity of MFADPSDE with traditional meth-
ods
Traditional method
Iosin
Iocos
Iosin/Iocos
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
323
Figure 323: Automatic adaptation of current magnitude supervision condition
(setting Min operate current) to either resistive part or amplitude of I1 ostab based
on the phase angle of accumulated sum admittance phasor, when setting Operating
quantity = "Adaptive". Directional mode = "Forward"
If the phase angle of accumulated sum admittance phasor is greater than 45
degrees, current magnitude supervision is based on the amplitude of
must exceed the set minimum operate current threshold. If the phase angle of
accumulated sum admittance phasor is below 45 degrees, current magnitude
supervision is based on the resistive part of
minimum operate current threshold. This automatic adaptation of the magnitude
supervision condition enables secure and dependable directional determination
in compensated networks, and it is also valid when the network is unearthed
(compensation coil is switched off).
If operation direction is set to reverse, the resistive and amplitude sectors are
mirrored in the operation characteristics.
564
Setting Operating quantity of MFADPSDE
).
+90 deg.

Tilt angle
-90 deg.
Adaptive
x
+45 deg.

0 deg.


1
I
o stab
Amplitude
x
, which must exceed the set
Technical Manual
1MRS759142 F
Resistive
x
Figure
1
I
, which
o stab
REX640