ABB Relion 620 Series - Page 529

faults. When the operation of the biased low stage is blocked by the second
harmonic blocking functionality, the BLKD2H output is activated.
When operation of the biased low stage is blocked by the fifth harmonic blocking
functionality, the BLKD5H output is activated. Correspondingly, when the operation
of the biased low stage is blocked by the waveform blocking functionality, the
BLKDWAV output is activated according to the phase information.
When required, the operate outputs of the biased low stage can be blocked by the
BLK_OPR_LS or BLOCK external control signals.
I
b2
I
d1
I
d2
I
b3
I
d3
100
200
300
100 200 300 400 500
End section 2End section 1
Low operate value
Section 1 Section 2 Section 3
I
d
[%Ir]
I
b
[%Ir]
Figure 272: Operation characteristic for biased operation of TR2PTDF
The Low operate value of the biased stage of the differential function is determined
according to the operation characteristic:
Low operate value = Id1
Slope section 2 and Slope section 3 are determined correspondingly:
Slope section
I
I
d
b
2 100
2
2
= ⋅ %
(Equation 75)
Slope section
I
I
d
b
3 100
3
3
= ⋅ %
(Equation 76)
The second turning point End section 2 can be set in the range of 100 percent to
500 percent.
1MRS757644 H
Protection functions
620 series
Technical Manual
529