GE 845 - Page 257

CHAPTER 4: SETPOINTS OUTPUTS
845 TRANSFORMER PROTECTION SYSTEM – INSTRUCTION MANUAL 4–129
CRITICAL FAILURE RELAY
The 8 Series relay is equipped with one output relay (# 8 - “Critical Failure Relay”) for
failsafe indication. The Critical Failure Relay is a Form-C contact with one NO and one NC
contact (no control power). There are no user-programmable setpoints associated with this
output relay.
NOTE
NOTE:
Please refer to “Self-Test Errors” section from the manual for details on the status of the
output relays during Relay Not Ready state, or detection of Major Self-Test error.
MAINTAINING AN UNINTERRUPTED PROCESS
The Output Relays are operational (can be closed/opened) while the 845 Transformer
Protection System
is In-Service. If the relay goes into “Out-of-Service” mode, the status of
all previously energized output relays changes to de-energized. If an output relay was
used to maintain a running process, or to hold a motor contactor while energized, the
process or the motor contactor will be interrupted. To keep the process uninterrupted, the
following connection scheme can be applied:
Figure 4-39: Maintaining an uninterrupted process upon a relay Major Error
Place selected Assigned/Non-assigned
Output Relays
Available/Hidden
Output Relays in:
Setpoints > Protection > Control >
Monitoring Elements
BKR [1-3] Trip Relay Select
BKR [1-3] Close Relay Select
SW [1-9] Open Relay Select
SW [1-9] Close Relay Select
Other Auxiliary Relays
Available
Hidden
Hidden
Hidden
Available
Output Relays in Control Elements with
Restoration Ability
BKR [1-3] Trip Relay Select
BKR [1-3] Close Relay Select
SW [1-9] Close Relay Select
SW [1-9] Open Relay Select
Other Auxiliary Relays
NOTE: The elements producing
close commands are directly
linked to their respective
breakers for closing/restoring.
Hidden
Hidden
Hidden
Hidden
Available
Setpoints > System > Switch [X] > Open
Relay Select
BKR [1-3] Trip Relay Select
BKR [1-3] Close Relay Select
SW [1-9] Close Relay Select
Other Auxiliary Relays
Hidden
Hidden
Hidden
Available
Setpoints > System > Switch [X] > Close
Relay Select
BKR [1-3] Trip Relay Select
BKR [1-3] Close Relay Select
SW [1-9] Open Relay Select
Other Auxiliary Relays
Hidden
Hidden
Hidden
Available
Setpoints > System > Breaker [X] > Trip
Relay Select
BKR [1-3] Close Relay Select
SW [1-9] Open Relay Select
SW [1-9] Close Relay Select
Other Auxiliary Relays
Hidden
Hidden
Hidden
Available
Setpoints > System > Breaker [X] > Close
Relay Select
BKR [1-3] Trip Relay Select
SW [1-9] Open Relay Select
SW [1-9] Close Relay Select
Other Auxiliary Relays
Hidden
Hidden
Hidden
Available