ABB RET670 - Page 67

Example on how to connect a neutral point VT to the IED
Figure 19 gives an example on how to connect a neutral point VT to the IED. This type
of VT connection presents secondary voltage proportional to V
0
to the IED.
In case of a solid ground fault in high impedance grounded or ungrounded systems the
primary value of V
0
voltage will be equal to:
0
3
ph ph
ph Gnd
V
V V
-
-= =
EQUATION1932 V2 EN (Equation 26)
Figure 19 gives an overview of required actions by the user in order to make this
measurement available to the built-in protection and control functions within the IED
as well.
Protected Object
19
20
21
22
23
24
13
14
15
16
17
18
A
B
C
AI07 (I)
AI08 (I)
AI09 (I)
AI10 (V)
AI11 (V)
AI12 (V)
IED
6.6
3
100
kV
V
R
Vo
1
2
3
4
ANSI06000603-2-en.vsd
5
SMAI2
BLOCK
^GRP2_A
^GRP2_B
^GRP2_C
^GRP2N
TYPE
AI3P
AI1
AI2
AI3
AI4
AIN
# Not Used
# Not Used
# Not Used
ANSI06000603 V2 EN
Figure 19: Neutral point connected VT
1MRK504116-UUS C Section 3
IED application
61
Application manual