GE P741 Technical Manual page 100

P74x/EN ST/Na7
(ST) 4-30
COMMISSION TESTS
Test Mode
The Test Mode menu cell is used to allow secondary injection testing to be performed on a
Peripheral Unit relay without operation of the connected zone. It also enables a facility to
directly test the output contacts by applying menu controlled test signals. To select test
mode the Test Mode menu cell should be set to 'Out of Service', which takes the relay out
of service. It also causes an alarm condition to be recorded and the yellow 'Out of Service'
LED to illuminate and an alarm message 'Out of Service' is given. The differential busbar
protection (87BB) and 50BF protection are in service as long as the cells '87BB Monitoring'
and '87BB & 50BF disabl' are equal to 0. Once testing is complete the cell must be set back
to 'Disabled' to restore the relay back to service.
Test Pattern
ST
Visible when "Test Mode" is disabled
This cell is used to select the output relay (or high break relay) contacts that will be tested
when the 'Contact Test' cell is set to 'Apply Test'.
Contact Test
Visible when "Test Mode" is disabled
When the 'Apply Test' command in this cell is issued the contacts set for operation (set to
'1') in the 'Test Pattern' cell change state. After the test has been applied the command text
on the LCD will change to 'No Operation' and the contacts will remain in the Test State until
reset issuing the 'Remove Test' command. The command text on the LCD will again revert
to 'No Operation' after the 'Remove Test' command has been issued.
Note:
Test LEDs
When the 'Apply Test' command in this cell is issued the eighteen user-programmable
LEDs will illuminate for approximately 2 seconds before they extinguish and the command
text on the LCD reverts to 'No Operation'.
87BB Monitoring
This cell is used to select the zone on which the differential busbar protection (87BB) will be
disabled.
87BB & 50BF disabl
Visible when "Test Mode" is disabled
This cell is used to select the zone on which the differential busbar (87BB) AND 50BF
protections will be disabled.
BB Trip Pattern
Visible when "Test Mode" is disabled
This cell is used to select the zone that will be tested when the 'BB Trip Command' cell is
set to 'Apply Test'.
Menu Text
Disabled
00000000
No Operation
When the 'Test Mode' cell is set to 'Enabled' the 'Relay O/P Status' cell does
not show the current status of the output relays and hence can not be used to
confirm operation of the output relays. Therefore it will be necessary to monitor
the state of each contact in turn.
No Operation
All bits set to 0
Each bit represents 1 zone
All bits set to 0
Each bit represents 1 zone
00000000
Default Setting
Settings
MiCOM P741, P742, P743
Available Settings
Disabled /Out Of Service
0 = Not Operated
1 = Operated
No Operation, Apply Test,
Remove Test
No Operation
Apply Test
0 = In Service
1 = 87BB blocked
0 = In Service
1 = 87BB and 50BF blocked
0 = In Service
1 = Out of Service