ABB RELION REX640 Technical Manual page 726

Protection functions
low stage is blocked by the waveform blocking functionality, the BLKDWAV output is
activated according to the phase information.
When required, the operating outputs of the biased low stage can be blocked by the
external control signals BLK_OPR_LS and BLOCK.
The operation of the protection relay is affected by biasing as shown in
Low operate value
Figure 411: Operation characteristic for biased operation of TR3PTDF
The
determined according to the operating characteristics curve:
Low operatevalue
The
Slope section 2 =
The second turning point
The slope of the operating characteristic curve of the differential function varies in
three different sections of the range.
726
I [%Ir]
d
300
200
100
I
d1
Section 1
End section 1
Low operate value setting of the biased stage of the differential function is
Id 1
=
Slope section 2 setting is determined correspondingly:
Id
2
100 %
⋅
Ib
2
I
b2
100 200
Section 2
End section 2
End section 2 can be set in the range 100...500 %.
I
b3
I
d3
I
d2
300 400
Section 3
Technical Manual
1MRS759142 F
Figure 411
.
500 I [%Ir]
b
(Equation 170)
(Equation 171)
REX640