ABB Relion 670 series - Example on How to Connect a Wye Connected Three-Phase CT Set to the IED

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.
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
4.2.2.5 Example on how to connect a wye connected three-phase CT set to the
IED
Figure 13 gives an example about the wiring of a wye connected two-phase CT set to the
IED. It 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.
For correct terminal designations, see the connection diagrams valid for
the delivered IED.
Section 4 1MRK 506 369-UUS -
Analog inputs
74 Line distance protection REL670 2.2 ANSI
Application manual