GE 845 Instruction Manual page 236

OUTPUTS
NOTE:
4–132
Auxiliary relays selected for Trip and Close
Operation of these breaker-control relays are designed to be controlled by the state of the
circuit breaker as monitored by a 52a contact, 52b contact, or both.
• The Trip and Close relays reset after a breaker is detected in a state corresponding to
the command. When a command is sent to one of these special relays, it will remain in
operation until the requested change of the breaker state is confirmed and the
initiating condition has Reset.
• If the command Resets without a change of breaker state, the output relay will be
Reset after a default interval of 2 seconds.
• If neither of the breaker auxiliary contacts, 52a and 52b, is programmed to a logic
input, the Trip Relay resets after a default interval of 100 ms after the initiating input
Resets. The Close Relay is Reset after 200 ms. If a delay is programmed for the Trip or
Close contact seal-in time, then this delay is added to the Reset time. Note that the
default setting for seal-in time is 100 ms.
The Trip and Close relay operation follows the logic described above only if the Relay Type
setpoint selected is Pulsed. If the selection is Latched, the relay is energized by any trip or
open command and remains energized upon element dropout. Latched auxiliary outputs
can be reset with a reset command. If Self-Reset type is selected, the output relay is
energized when the corresponding element operates and it stays energized until the
element drops out.
52a Contact Configured
Yes
Yes
No
No
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.
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.
Output Relays application to maintain 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 relay changes to de-energized. If an output relay was used
52b Contact Configured
Yes
No
Yes
No
845 TRANSFORMER PROTECTION SYSTEM – INSTRUCTION MANUAL
CHAPTER 4: SETPOINTS
Relay Operation
The Trip Relay and Close Relay continue
operating until the breaker is detected
opened or closed using both 52a and
52b contacts as per the breaker
detection logic.
The Trip Relay continues operating until
52a indicates an open breaker. The
Close Relay continues operating until
52a indicates a closed breaker.
The Trip Relay continues operating until
52b indicates an open breaker. The
Close Relay continues operating until
52b indicates a closed breaker.
Trip Relay operates upon a Trip
command and stays "high" until the
100 ms default time expires. The Close
Relay operates upon a Close command
and Resets after the 200 ms time
expires.