ABB eVM1 Installation And Service Instructions Manual page 52

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14.5.5.6 Energy Failure Autotrip
The IED monitors the charge of the capacitors, continuously checking the voltage. When the CB is
in the closed position there must be enough energy to carry out the opening operation (O), while if
the CB is open there must be enough energy to close and then to open (CO) it. If there is not
enough energy (level 'KO'), the CB must be locked in its position or opened if the Energy Failure
Autotrip function is enabled
When Energy Failure Autotrip is enabled it will make the CB open when the external power supply
is shut down or there is an internal energy failure. The Opening operation is typically performed
within 1-2 minutes after auxiliary power failure depending on CB ratings, and the delay is due to
discharging of energy stored in the internal capacitor by the IED.
An Anomaly alarm is issued and the No Anomaly LED on the CB HMI goes ON.
Link Capacitor
I/O Input Level
Level 'OK'
Level 'KO'
Fig. 38
The system is in 'Energy Failure status' when the capacitor charge is under the Othreshold ('KO'
level).
The following behaviour is allowed:
Capacitor Charge
Energy sufficient for O-CO operations
Energy sufficient for CO operations
Energy sufficient for O operations
Energy insufficient for any operation
14.5.5.7 UnderVoltage
The IED monitors the voltage on UnderVoltage Binary input DI1 and the value is processed.
When the UnderVoltage function is enabled it will make the CB open when an undervoltage condition
is detected; i.e. when the voltage drops below 70% of its nominal value. The UnderVoltage condition
will only be reset when the voltage on DI1 becomes higher than 85% (ref. to IEC 60694.5.8.4).
The nominal voltage value is selected by setting the Dip-Switches S1 ... S4 on the I/O board.
Othr COthr Capacitor Voltage [V]
CB position Closed
Opening allowed
Opening allowed
Opening allowed
Blocked in closed position
or CB immediately opened
Open
Closing allowed
Closing allowed
Blocked in open position
Blocked in open position