ABB RET670 - Page 57

A
(H1)
B
(H2)
b
(X2)
a
(X1)
A
(H1)
N
(H2)
n
(X2)
a
(X1)
b) c)
A
(H1)
N
(H2)
dn
(X2)
da
(X1)
d)
V
Pri
+ +
V
Sec
a)
ANSI11000175_1_en.vsd
ANSI11000175 V1 EN
Figure 14: Commonly used markings of VT terminals
Where:
a) is the symbol and terminal marking used in this document. Terminals marked with a dot
indicate the primary and secondary winding terminals with the same (positive) polarity
b) is the equivalent symbol and terminal marking used by IEC (ANSI) standard for phase-to-
ground connected VTs
c) is the equivalent symbol and terminal marking used by IEC (ANSI) standard for open delta
connected VTs
d) is the equivalent symbol and terminal marking used by IEC (ANSI) standard for phase-to-phase
connected VTs
It shall be noted that depending on national standard and utility practices the rated
secondary voltage of a VT has typically one of the following values:
• 100 V
• 110 V
• 115 V
• 120 V
• 230 V
The IED fully supports all of these values and most of them will be shown in the
following examples.
Examples on how to connect a three phase-to-ground connected VT to
the IED
Figure
15 gives an example on how to connect the three phase-to-ground connected
VT to the IED. It as well gives 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.
For correct terminal designations, see the connection diagrams valid for
the delivered IED.
1MRK504116-UUS C Section 3
IED application
51
Application manual