ABB RELION REX640 Technical Manual page 636

Section 4
Protection functions
630
I_A1
I_B1
I3P1
I_C1
I_A2
I_B2
I3P2
I_C2
I_A3
I_B3
I3P3
I_C3
TAP_POS
BLK_OPR_HS
BLOCK
BLK_OPR_LS
GUID-0E72DED7-0217-4F6C-9D9A-33B43B256F07 V2 EN
Figure 347: 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.
I
W 1
GUID-DA57E921-C010-4703-9652-06A17F64DFB3 V1 EN
Figure 348: Single-line diagram of the positive direction of the currents in a three-
winding transformer
Differential
calculation
Transformer
vector group
matching
Instantaneo
us high
Zero-sequence
component
elimination
Compensation
of tap changer
position
Second
harmonic
blocking
Biased
Fifth harmonic
low stage
blocking
Waveform
blocking
(usually tertiary)
Winding 1
(usually HV)
(usually LV)
1MRS759142 C
OPERATE
OR
stage
OPR_HS
OPR_LS
BLKDWAV
Winding 3
I
W 3
I
W 2
Winding 2
Technical Manual
BLKD2H
BLKD5H
REX640