Protection Functions; Stabilized Three-Phase Differential Protection Mpdif - ABB RELION 630 Series Applications Manual

1MRS757582 C
3.2.6
3.2.6.1
REG630
Application Manual

Protection functions

Stabilized three-phase differential protection MPDIF

Stabilized three-phase differential protection with low (biased) stage and high
(instantaneous) stage is used for protecting a generator against winding failure. The
function includes a DC restraint feature. This feature temporarily decreases the
sensitivity of the differential protection to avoid unnecessary disconnection of the
generator when DC current is detected. The function also includes a CT saturation
based blocking.
The set of three phase currents from the line side I3P, neutral side I3P_N, and the three
phase voltages U3P are connected to the inputs.
The operate signal from the low and high stages provides a LED indication on the
LHMI. The low stage and high stage operate outputs are connected to the disturbance
recorder.
L1
L2
L3
P1
S1
S2
P2
P1 S1
S2
P2
G
S1
S2
P1 S1
S2
P2
GUID-E47AA21C-EDED-4440-8385-B4BDE23114FF V1 EN
Figure 10: Generator differential and thermal overload protection
I
AIM
0
0
X101
1
IL1
2
3
IL2 3I
4
5
IL3
6
7
Io
8
9
IL1
10
AIM
IL1
X102
1
3I_N
IL2
2
3
IL3
4
5
U1
6
7
U2 3U
8
9
U3
10
Section 3
REG630 variants
THERMAL OVERLOAD PROTECTION
T2PTTR(1)
30>G
49T/49G
COMMON
3I OPERATE
OPERATE
COMMON
BLK_OPR ALARM
START
PO5
MPDIF(1)
I>M
87G/87M
COMMON
3I
I3P1 OPERATE
OPERATE
3I_N I3P2
3U
U3P INT_BLKD
DIFF_BLKD
BLOCK
PSM
X327
9
10
31