ABB REG316 4 Series Operating Instructions Manual page 274

ABB Switzerland Ltd
Important note:
The tripping and alarm outputs are disabled as long as one of
the two binary Inputs 'AdjMTRInp' or 'AdjREsInp' is enabled,
i.e. the protection will not trip if the stator circuit is grounded.
The two signals 'InterruptInt' and 'InterruptExt', however, are
not disabled.
REs and MTR in the case of primary injection at the
generator star-point
An injection transformer block Type REX 011 is needed for this
circuit.
Fig. 3.5.24.1 shows the wiring diagram for primary injection
(peak value of U
is
The star-point is grounded via the resistor R
resistor R . The current at the star-point must not exceed 20 A.
Ps
It is recommended, however, to select the resistors such that the
star-point current is £ 5 A to protect as much of the winding as
possible.
The total resistance is thus:
+
Condition 1: R
Es
where: U
Gen
I
Emax
The following conditions must also be fulfilled:
³
Condition 2: R 130
Ps
³
Condition 3: R
Es
³
Condition 4: R 0.7 k
Es
The v.t. must be designed such that for a solid ground fault at
the generator terminals, the rated frequency component voltage
Us = 100 ±20 %, i.e. the ratio MTR = N
following range:
Condition 5:
N
´ ³ 12 ³
1.2 n 0.8 n
N
11
U
N
12 Gen
A v.t. =
N ´
3 100 V
11
3-236
REG 316*4 1MRB520049-Uen / Rev. F
110 or 96 V DC) at the generator star-point.
U
Gen
³
R
Ps
´
3 I
Emax
phase-to-phase voltage at the generator
terminals
max. star-point current = 20 A
W and R £
500
Ps
´
4.5 R
Ps
W and R £
5 k
Es
´ , where n =
will fulfil condition 5 in most cases.
and the parallel
Es
W
W
/ N must lie within the
12 11
U
R
Gen Es
´
+
´ R R
3 100 V
Es Ps