Trip And Close Circuit Monitoring - GE 845 Instruction Manual

MONITORING

Trip and Close Circuit Monitoring

4–252
The 845 relay provides Trip and Close Circuit Monitoring elements.
The first and second Form A relay outputs on slot "F" include a circuit to monitor the DC
voltage across the output contact when it is open. To do that, an external jumper is wired
between the terminals "FA_1 COM" and "FA_1 OPT/V" for the Trip coil monitoring, or/and
"FA_2 COM" and "FA_2 OPT/V" for the Close coil monitoring.
The monitor contains a level detector whose output is set to logic 1 (ON) when the voltage
is above 20 volts. The voltage monitor is used to check the health of the overall trip and
closing circuit.
The two figures below show the two different connections of the breaker trip and close
coils to the relay's trip and close output relays for either no voltage monitoring and for
voltage monitoring of the circuits.
Figure 4-98: Trip Coil Circuit without Monitoring
Figure 4-99: Close Coil Circuit without Monitoring
Output Relay 2 (CLOSE)
Output Relay 1 (TRIP)
FA_1
COM
FA_1
NO
V
FA_1
OPT/V
FA_2
COM
FA_2
NO
V
FA_2
OPT/V
845 TRANSFORMER PROTECTION SYSTEM – INSTRUCTION MANUAL
CHAPTER 4: SETPOINTS
DC +
52a
contact
Trip
Coil
DC -
DC +
52b
contact
Close
Coil
DC -