4–368 850 FEEDER PROTECTION SYSTEM – INSTRUCTION MANUAL
CONTROL CHAPTER 4: SETPOINTS
A practical scheme for overall TRANSFER READY indication can be developed by selecting
all three 850
relays to operate one of the spare Auxiliary Output relays, and wiring the
relays in series with a DC source to turn on a single light bulb (“white light”). The Auxiliary
Output relay from each 850
relay can also be wired to turn on an individual light bulb.
The TRANSFER READY flag is high, if all of the following conditions are met:
Incomer 1 Relay:
• The “Incomer 1” setting is selected under the TRANSFER FUNCTION setpoint
• The transfer scheme is not blocked from the “Block Transfer” input
• Bus Tie Breaker is racked-in (connected) and open
• Incomer 1 Breaker is racked-in (connected) and closed
• Incomer 2 Breaker is racked-in (connected) and closed
• No transformer lockout or source trip is present
• No undervoltage is detected on any of the two sources
• No faults on the load side of the circuit breaker.
Incomer 2 Relay:
• The “Incomer 2” setting is selected under the TRANSFER FUNCTION setpoint
• The transfer scheme is not blocked from the “Block Transfer” input
• Bus Tie Breaker is racked-in (connected) and open
• Incomer 1 Breaker is racked-in (connected) and closed
• Incomer 2 Breaker is racked-in (connected) and closed
• No transformer lockout, or source trip is present
• No undervoltage is detected on any of the two sources
• No faults on the load side of the circuit breaker.
Tie Breaker Relay:
• The “Bus Tie” setting is selected under the TRANSFER FUNCTION setpoint
• The transfer is not blocked from the “Block Transfer” input
• Bus Tie Breaker is racked-in (connected) and open
• Incomer 1 breaker is racked-in (connected) and closed
• Incomer 2 breaker is racked-in (connected) and closed.
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