Manual 37137B
ESDR 4 - Current Differential Protection Relay
© Woodward
Page 17/35
Control Inputs
Configuration
Terminal 17
When this input is energized, the unit locks into Configuration mode and stays in this
mode until the terminal is de-energized.
Acknowledgement
Terminal 18
If this input remains energized for at least 1 s, the faults detected in monitoring
level 2 are reset. This means that the relays will be de-energized and the text display
will be deleted from the screen as long as the monitored currents are not exceeding
the configured threshold level.
Blocking
Terminal19
When this input is energized, the differential protection is disabled.This means that
the differential current is not monitored, no relay can be enabled and no text is dis-
played.
Relays
Tripping (relay 1)
Terminals 1/2/3
This relay becomes enabled when the unit detects threshold limit 2 (main stage) has
been exceeded. The configured differential current characteristics and delay time will
determine how relay 1 functions.
Tripping (relay 2)
Terminals 4/5/6
This relay becomes enabled when the unit detects threshold limit 2 (main stage) has
been exceeded. The configured differential current characteristics and delay time will
determine how relay 2 functions.
Warning (relay 4)
Terminals 11/12/13
This relay becomes enabled when the unit detects threshold limit 1 has been ex-
ceeded. The configured differential current characteristics and delay time will deter-
mine how relay 4 functions.
Ready for operation
(relay 3)
Terminals 7/8
This relay is enabled when the unit is operational and the differential current is being
monitored. The relay becomes disabled if the monitoring is deactivated through any
of the following reasons:
•
the internal self-monitoring has detected a malfunction of the unit. A correct func-
tioning of the unit cannot be guaranteed and corrective action may be necessary.
•
the set values for parameter "CT-ratio" or parameter "Generator Current" are out-
side the permissible limits (see page 19).
•
the digital input "Blocking" is energized.
•
the parameter "Monitoring" is configured to "Off".
