Fault Records; Demand/Data Log; Metering - Siemens 7SR242 Manual

7SR242 Duobias Description Of Operation
In total the relay provides 10 seconds of waveform storage, this is user selectable to 1 x 10second, 2 x 5 second,
5 x 2 second or 10 x 1 second records. When the waveform recorder buffer is full any new waveform record will
over-write the oldest. The most recent record is Waveform 1.
As well as defining the stored waveform record duration the user can select the percentage of the waveform
storage prior to triggering.
Waveforms are sampled at a rate of 1600Hz.
Stored waveforms can be erased using the DATA STORAGE>Clear Waveforms setting.

6.3.4 Fault Records

Up to ten fault records can be stored and displayed on the Fascia LCD.
Fault records provide a summary of the relay status at the time of trip, i.e. the element that issued the trip, any
elements that were picked up, the fault type, LED indications, date and time. The Max Fault Rec. Time setting
sets the time period from fault trigger during which the operation of any LEDs is recorded.
To achieve accurate instrumentation values for the fault records when testing, ensure a drop off delay is applied
to the test set so that the injected quantities remain on for a short duration, typically 20ms, after the relay has
issued the trip output. This extended period of injection simulates the behaviour of the power system where
faulted conditions are present until CB operation.
Where examined together the event records and the fault records will detail the full sequence of events leading to
a trip.
Fault records are stored in a rolling buffer, with the oldest faults overwritten. The fault storage can be cleared with
the DATA STORAGE>Clear Faults setting.
The SYSTEM CONFIG > Trip Alert = Disabled setting allows the above to be switched off e.g. during
commissioning tests.

6.3.5 Demand/Data Log

The Data log feature can be used to build trend and demand records.
Up to 10,080 values for each phase current (W1 and W2) and voltage (where fitted) analogue are recorded. Each
recorded value consists of the mean value of the sampled data over the Data Log Period.
Stored Data Log records are retrieved using Reydisp.
6.4

Metering

The metering feature provides real-time data available from the relay fascia in the 'Instruments Mode' or via the
data communications interface.
For a detailed description refer to Technical Manual Chapter 2 – Settings and Instruments.
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