ABB RELION REX640 - Page 718

BLK_OPR_LS
BLK_OPR_HS
Biased
low stage
Instantaneo
us high
stage
OPERATE
OPR_LS
OPR_HS
BLKD2H
BLKD5H
BLKDWAV
OR
I3P1
I_A1
I_B1
I_C1
I3P2
I_A2
I_B2
I_C2
BLOCK
Second
harmonic
blocking
Fifth harmonic
blocking
Waveform
blocking
Compensation
of tap changer
position
Differential
calculation
Transformer
vector group
matching
Zero-sequence
component
elimination
I3P3
I_A3
I_B3
I_C3
TAP_POS
Figure 406: Functional module diagram
Differential calculation
TR3PTDF operates phasewise on the difference of incoming and outgoing currents.
The positive direction of the currents is towards the protected object.
Winding 1
(usually HV)
Winding 2
(usually LV)
1W
I
Winding 3
(usually tertiary)
2W
I
3W
I
Figure 407: Single-line diagram of the positive direction of the currents in a
threewinding transformer
The normalized amplitude of the differential current per phase Id is obtained using
the equation:
Protection functions
1MRS759142 F
718 REX640
Technical Manual