Hitachi Relion 670 Series Applications Manual page 56

Section 4
Analog inputs
a)
IEC06000641 V1 EN-US
Figure 13:
Where:
a)
b) and c) are equivalent symbols and terminal marking used by IEC (ANSI) standard for CTs. Note that
It shall be noted that depending on national standard and utility practices, the rated secondary
current of a CT has typically one of the following values:
• 1A
• 5A
However, in some cases, the following rated secondary currents are used as well:
• 2A
• 10A
The IED fully supports all of these rated secondary values.
4.2.2.5 Example on how to connect a star connected two-phase CT set to the IED
Figure 14
gives an overview of the actions which are needed to make this measurement available to the built-in
protection and control functions within the IED as well.
50
P1
(H1)
I
Sec
x
P2
(H2)
Commonly used markings of CT terminals
is symbol and terminal marking used in this document. Terminals marked with a square
indicates the primary and secondary winding terminals with the same (that is, positive) polarity
for these two cases the CT polarity marking is correct!
It is recommended to:
• use 1A rated CT input into the IED in order to connect CTs with 1A and 2A
secondary rating
• use 5A rated CT input into the IED in order to connect CTs with 5A and 10A
secondary rating
gives an example about the wiring of a star connected two-phase CT set to the IED. It
For correct terminal designations, see the connection diagrams valid for the delivered
IED.
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(H2)
S1 (X1)
S2 (X2)
x
(H1)
b)
1MRK506375-UEN Rev. N
P2
S2 (X2)
S1 (X1)
P1
c)
en06000641.vsd
Railway application RER670
Application manual
SEMOD55055-352 v13