Rockwell Automation 865 Differential Protection Relay - Manual (Page 37)

Local Panel User Interface 2-25
865-UM001A-EN-P – July 2009
Configuration Menu CONF
The following functions and features can be read and set via the
submenus of the configuration menu:
DEVICE SETUP
•
Bit rate for the command line interface in ports X4 and the front
panel. The front panel is always using this setting. If SPABUS
is selected for the rear panel local port X4, the bit rate is
according SPABUS settings.
•
Access level [Acc]
LANGUAGE
•
List of available languages in the relay
CURRENT SCALING
•
Rated phase CT primary current (Inom)
•
Rated phase CT secondary current (Isec)
•
Rated input of the relay [Iinput]. 5 A or 1 A. This is specified in
the order code of the device.
•
Rated phase CT’ primary current (I’nom)
•
Rated phase CT’ secondary current (I’sec)
•
Rated input of the relay [I’input]. 5 A or 1 A. This is specified in
the order code of the device.
•
Rated value of I
0
CT primary current (Ionom)
•
Rated value of I
0
CT secondary current (Iosec)
•
Rated I01 input of the relay [Ioinp]. 5 A or 1 A. This is specified
in the order code of the device.
•
Rated value of I
02
CT primary current (Io2nom)
•
Rated value of I 02 CT secondary current (Io2sec)
•
Rated I02 input of the relay [Io2inp]. 5A, 1 A or 0.2 A. This is
specified in the order code of the device.
The rated input values are usually equal to the rated secondary
value of the CT.
The rated CT secondary may be greater than the rated input but
the continuous current must be less than four times the rated
input. In compensated, high impedance earthed and isolated
networks using cable transformer to measure residual current I
0
,
it is quite usual to use a relay with 1 A or 0.2 A input although
the CT is 5 A or 1A. This increases the measurement accuracy.
The rated CT secondary may also be less than the rated input but
the measurement accuracy near zero current will decrease.