ABB REG316 4 Series Operating Instructions Manual page 281

REG 316*4 1MRB520049-Uen / Rev. F
REs and MTR in the case of secondary injection at the
generator terminals
An injection transformer block Type REX 011-2 is needed for this
circuit.
The bias voltage can also be injected across part of the
grounding resistor connected to the broken-delta secondaries of
a grounding v.t's at the generator terminals
The two resistors R'
star-point which must not exceed 20 A. The total resistance is
thus :
Condition 1:
+
R'
Es
where: U
Gen
I
Emax
N /N
1
The grounding resistors R'
conditions:
Condition 2:
³
R'
Ps
Condition 3: R'
Es
Condition 4:
³
R'
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 V ±20 %, i.e. the ratio MTR' = N'
the following range:
Condition 5:
N'
12
1.2 n ´ ³ ³ 0.8 n ´
N'
11
N' U
A v.t.
12 Gen
=
N' ´
3 100 V
11
The settings for R
Es
the values of R'
Es
grounding transformer:
and R' limit the maximum current at the
Es Ps
æ
´
U 3 N
Gen
³ ´
R' ç
Ps
´ è N
3 I
Emax
phase-to-phase voltage at the generator
terminals
max. star-point current = 20 A
ratio of the grounding transformer.
2
and R'
Es Ps
2
æ ö
´
3 N
and
2
W ´
130 ç ÷
è N ø
1
³ ´
4.5 R'
Ps
2
æ ö
3 N ´
and
2
W ´
0.7 k ç ÷
è N ø
1
U
, where
Gen
=
n
3 100 V ´
´
3 N
will fulfil condition 5 in most cases.
2
´
N
1
and MTR must be entered via the HMC, i.e.
and MTR' reflected to the primary of the
ABB Switzerland Ltd
(see Fig. 3.5.24.3).
2
ö
2
÷
ø
1
must fulfil the following
æ
´
3 N
£ W ´
R' 500 ç
Ps
N
è
1
æ
3 N ´
£ W ´
R' 5.0 k ç
Es
è N
/ N' must lie within
12 11
´ R'
3 N
2 Es
´ ´
+
N R' R'
1 Es Ps
2
ö
2
÷
ø
2
ö
2
÷
ø
1
3-243