The Fusesaver has a mechanism fault.
Both LEDs will be off under the following circumstances:
There is no Fusesaver for that phase.
The RCU is currently in the process of checking the Fusesaver configuration (RCU Switchgear
OK LED will be flashing)
The state of the Fusesaver Communications Module, Fusesaver VI or Fusesaver Mechanism is
unknown as data for these points has not been updated recently.
8.3 Time Management
The RCU has in internal real time clock which runs on Universal Coordinated Time (UTC).
Is operation in the case of a CMR installation is described in [1] .The following refers to Fusesaver
installations.
Time is set by the SCADA protocol (if supported by the protocol and the master station). Time is
maintained in the RCU during loss of supply by using the standby battery. If the battery is
disconnected or turned off for more than 1 hour, time may be lost and must be reset when power is
restored to the RCU, usually the SCADA protocol will do this.
On power up the RCU acquires time from the following sources in this order:-
The battery backed up clock
The SCADA system
The Fusesaver time master if SCADA time not acquired.
The RCU sets time in the Fusesavers every 24 hours and when time is set by the SCADA system.
Note that the earliest time that the RCU will accept from SCADA is 1
st
January 2011. A time earlier
than this will not be accepted by the RCU.
8.4 Fusesaver Availability Monitoring
The following functionality is available for Fusesaver installations only.
For Fusesavers configured to work with a partner fuse (i.e. configured for OC operation), the
Fusesaver protection is only armed when the line current is sufficient to power the Fusesaver (line
power is needed for protection even if a Communications Module is fitted). At times of low demand
it is possible that the line current will fall low enough such that the Fusesaver protection is inactive.
It can be difficult to ascertain if a particular line has enough current for some or all of the day for the
Fusesaver protection to be armed. Fusesavers installed on sites with inadequate line current will
not provide the improved network reliability and return on investment potentially forecast by the user.
To assist the user in assessing that Fusesavers have been installed on lines with adequate line
current the RCU monitors the line current ON flag in the Fusesaver and determines the Fusesaver
protection availability over the previous 24 hours for which Fusesaver data is available. The RCU
then provides this as an analogue database point for the SCADA system (APID 23, 24, 25). This
enables SCADA monitoring of the Fusesaver protection availability.
These points are updated every 2.4 hours and are initialised to 100.00% on restart.
Note that no line current due to the Fusesaver being open is included as an outage in the availability
calculation.
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