D90
PLUS
LINE DISTANCE PROTECTION SYSTEM – INSTRUCTION MANUAL 505
D90
Plus
Line Distance Protection System
Chapter 10: Digital fault recorder
Digital f ault recorder
The digital fault recorder (DFR) captures detailed information regarding abnormal
occurrences in the power system. The information captured by the DFR is stored in the
D90
Plus
in non-volatile memory and can be accessed through the front panel interface. The
DFR consists of the following four functions:
• An event recorder that provides a time-stamped record of the operation of breakers,
protection elements, and alarms. Event recording is enabled on a per-element basis.
• A fault report that records fault type, magnitude, and duration of the fault, and the
response of protection functions
• A transient recorder that records analog and digital signals for short duration events
at a high resolution
• A disturbance recorder that records analog and digital signals for long duration
events, such as power swings and voltage sags, at a resolution of one sample per
cycle
Sequence of events recorder
This event recorder provides a time-stamped record of state changes of signals monitored
by the D90
Plus
. These signals include the state of circuit breakers and disconnect switches,
external alarms and indications, and any of the internal functions of the IED. The
D90
Plus
can store a total of 8192 events. Once this memory is filled, the oldest events are
overwritten.
Most D90
Plus
elements contain an Events setting. When this setting is enabled, state
changes for FlexLogic operands associated with the element are written to the event
recorder. If this setting is disabled then state changes for the element are not recorded.
Front panel operation
The sequence of events record can be accessed from the front panel through the digital
fault recorder (DFR) page. Using the navigation keys, the user can scroll or page through
the events list. Two cursors are provided for measurement of the time difference between
events.
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