Other Features; Flash Memory; Line Overload; Current Unbalance Detection - GE LPS-O Instruction Manual

1.5 OTHER FEATURES

1 PRODUCT DESCRIPTION
1.5 OTHER FEATURES

1.5.1 FLASH MEMORY

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The program code resides in Flash memory rather than the EPROM. This new technology provides the same
functionality during normal operations of the relay. The advantage to the Flash Memory is it allows for software
upgrades without opening the relay. The Flash contents can be overwritten through the communications ports
provided in the relay. This procedure requires special software which does not come with the standard commu-
nications packages available for the LPS-O.

1.5.2 LINE OVERLOAD

The Line Overload function provides an event and a programmable signal. This signal can be used to provide
alarm indication (contact closure) that the load current on the protected line has exceeded a set level for a set
time interval. Two alarm levels are included. Level 1 is generally set with a lower pickup setting and a longer
time delay than level 2.

1.5.3 CURRENT UNBALANCE DETECTION

If the Fault Detector, FD, remains picked up for 60 seconds, a non-critical alarm is issued and an event mes-
sage generated. This function indicates sustained unbalanced current conditions such as an open or shorted
current transformer.

1.5.4 FAULT REPORT

When a fault or oscillography trigger occurs, pertinent information (consisting of unit ID, date and time, operat-
ing time, prefault currents, fault currents and voltages, fault type, trip type, and selected events) is stored in
memory. The number of fault events that are stored is selectable by the user and may be set for 6, 12, 24, or
36 events. Each fault report is associated with an oscillography data file. See Chapters 8: LOCAL USER
INTERFACE and 11: LPSO-LINK USER GUIDE for a complete description of the Fault Report function.

1.5.5 OSCILLOGRAPHY

Oscillography data are stored in memory each time the LPS-O issues a trip and, optionally, when an internal
oscillography trigger flag is set or an external contact closed. Protection Setting 1626: CONFOSC allows a
configurable oscillography trigger to be assigned by Xpression Builder.
Note that the OSC Trigger stores oscillography data, but does not necessarily set t = 0, where t is the time
sample that delineates between prefault and postfault oscillography cycles. The term disturbance period is
defined as the number of cycles of oscillography data (prefault plus postfault) as determined by General Set-
ting 301: NUMFLTS. If the internal Fault Detector (FD) comes up initially and OSC Trigger follows within the
disturbance period, oscillography data are stored whether or not the LPS-O issues a trip.
If the LPS-O issues a trip, then a normal fault report is stored as part of the oscillography data. If the LPS-O
does not issue a trip, a pseudofault report is created. The trip type is listed as OSC, the trip time is the time of
the OSC Trigger, the operating time is set to zero, and the fault type and location are computed with post-OSC
Trigger data. The local LCD display does not show target information, but an event message and fault report
are stored in memory. In either case, t = 0 is determined by the internal Fault Detector (FD).
If OSC Trigger comes up initially and FD follows within the disturbance period, the same actions occur and FD
determines t = 0. If only OSC Trigger occurs, then a pseudofault report is created and OSC Trigger determines
t = 0. This arrangement assures that the oscillography function always captures an LPS-O trip, with FD deter-
mining t = 0, regardless of whether an optional internal or external trigger is used.
1- LPS-O Line Protection System GE Power Management
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