ABB RELION RET670, Commissioning Manual, Page: 64 / 328

5.2 Configuring analog CT inputs
The analog input channels must be configured to get correct measurement results as well
as correct protection functionality. Because all protection algorithms in the IED utilize the
primary system quantities, it is extremely important to make sure that connected current
transformer settings are done properly. These data are calculated by the system engineer
and normally set by the commissioning personnel from the local HMI or from PCM600.
The analog inputs on the transformer input module are dimensioned for either 1A or 5A.
Each transformer input module has a unique combination of current and voltage inputs.
Make sure the input current rating is correct and that it matches the order documentation.
The primary CT data are entered via the HMI menu under Main menu/Configurations/
Analog modules
The following parameter shall be set for every current transformer connected to the IED:
Table 9: CT configuration
Parameter description Parameter name Range Default
Rated CT primary current in A CTPRIMn
n = channel number
from 0 to 99999 3000
This parameter defines the primary rated current of the CT. For two set of CTs with ratio
1000/1 and 1000/5 this parameter is set to the same value of 1000 for both CT inputs. The
parameter
CTStarPoint can be used in order to reverse the direction of the CT. This might
be necessary if two sets of CTs have different neutral (WYE) point locations in relation to
the protected busbar.
For main CTs with 2A rated secondary current, it is recommended to connect the
secondary wiring to the 1A input.
Take the rated permissive overload values for the current inputs into
consideration.
5.3 Supervision of input/output modules
I/O modules configured with PCM600 (BIM, BOM or IOM) are supervised.
I/O modules that are not configured are not supervised.
Section 5
1MRK 504 165-UUS -
Configuring the IED and changing settings
58 Transformer protection RET670 2.2 ANSI
Commissioning manual