3.2.6
Protection functions
3.2.6.1
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
S1
S2
P1
P2
X101
IL1
IL2
IL3
Io
P2
P1
S1
S2
1
3
4
0
0
I
U1
U2
U3
X102
3U
2
5
6
7
8
9
10
1
2
3
4
5
6
7
8
9
10
AIM
AIM
G
3I
IL1
IL2
IL3
3I_N
S1
S2
IL1
P2
P1
S1
S2
THERMAL OVERLOAD PROTECTION
3I_N
3I
COMMON
OPERATE
DIFF_BLKD
9
10
X327
PSM
PO5
COMMON
OPERATE
30>G
T2PTTR(1)
OPERATE
ALARM
49T/49G
3I
BLK_OPR
I>M
MPDIF(1)
OPERATE
INT_BLKD
I3P2
BLOCK
87G/87M
I3P1
U3P
3U
COMMON
START
GUID-E47AA21C-EDED-4440-8385-B4BDE23114FF V1 EN
Figure 10:
Generator differential and thermal overload protection
1MRS757582 C
Section 3
REG630 variants
REG630
31
Application Manual
Summary of Contents for Relion 630 Series
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