ABB RELION 650 Series Applications Manual page 62

Section 4
Analog inputs
In case of a solid earth fault in high impedance earthed or unearthed systems the primary
value of Uo voltage will be equal to:
U
Ph
=
U 0
EQUATION1931 V2 EN-US
Figure 20gives 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.
IEC06000603 V4 EN-US
Figure 20: Neutral point connected VT
Where:
1)
2)
Table continues on next page
56
-
Ph
=
U
-
Ph E
3
Protected Object
L1 L2
R
shows how to connect the secondary side of neutral point VT to one VT input in the IED.
U shall be connected to the IED.
0
is the TRM or AIM where this voltage input is located. For this voltage input the following setting
values shall be entered:
6.6
= =
VTprim 3.81 kV
3
EQUATION1933 V1 EN-US
=
VT sec 100 V
EQUATION1934 V1 EN-US
Inside the IED, only the ratio of these two parameters is used. It shall be noted that the ratio of the
entered values exactly corresponds to ratio of the neutral point VT.
IED
L3
1
Uo
6.6 kV
3
100 V
1MRK 505 363-UEN A
2
3
SMAI2
BLOCK
REVROT
^GRP2L1
# Not Used
# Not Used
^GRP2L2
# Not Used ^GRP2L3
^GRP2N
4
IEC06000603-4-en.vsdx
Application manual
(Equation 11)
5
AI3P
AI1
AI2
AI3
AI4
AIN
(Equation 12)
(Equation 13)