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7SR157 Technical Manual
6.3 Data Storage
6.3.1
General
The relay stores three types of data: relay event records, analogue/digital waveform records and fault records.
Data records are backed up in non-volatile memory and are permanently stored even in the event of loss of
auxiliary supply voltage.
features.
6.3.2
Event Records
The event recorder feature allows the time tagging of any change of state (Event) in the relay. As an event
occurs, the actual event condition is logged as a record along with a time and date stamp to a resolution of 1
millisecond. There is capacity for a maximum of 1000 event records that can be stored in the relay and when the
event buffer is full any new record will over-write the oldest. Stored events can be erased using the DATA
STORAGE>Clear Events setting or from Reydisp.
The following events are logged:
Change of state of Binary outputs.
Change of state of Binary inputs.
Change of Settings and Settings Group.
Change of state of any of the control functions of the relay.
Protection element operation.
All events can be uploaded over the data communications channel(s) and can be displayed in the 'Reydisp'
package in chronological order, allowing the sequence of events to be viewed. Events can be selected to be
made available spontaneously to an IEC 60870-5-103, Modbus RTU or DNP 3.0 compliant control system. The
function number and event number can also be changed. The events are selected and edited using the Reydisp
software tool.
For a complete listing of events available in each model, refer to Technical Manual Section 4 'Data
Communications Definitions'.
6.3.3
Waveform Records.
Relay waveform storage can be triggered either by user selected relay operations, from the relay fascia, from a
suitably programmed binary input or via the data communications channel(s). The stored analogue and digital
waveforms illustrate the system and relay conditions at the time of trigger. An output is provided to indicate when
a new record has been stored.
A waveform can also be stored from the fascia using the DATA STORAGE > Trigger Waveform setting.
In total the relay provides up to 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 or from Reydisp.
6.3.4
Fault Data Records
Up to ten fault records can be stored and displayed on the Fascia LCD. Fault records can be triggered by a
suitably programmed binary input. The 7SR157 does not provide any protection or system fault detection
functionality but will record data in the same format as other 7SR products fault records. An output is provided to
indicate when a new record has been stored.
Fault records provide a summary of the relay status at the time of trigger, i.e. the Bus and Line voltage levels,
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.
The relay can be set to automatically display the fault record on the LCD when a fault occurs by enabling the
SYSTEM CONFIG> Trip Alert setting. When the trip alert is enabled the fault record will be displayed until the
fault is removed.
With the Trip Alert setting enabled the user will have to press the TEST/RESET► button three times in order to
return to the home screen after a trip has occurred. The user will then have to press the TEST/RESET► button a
further time (four in total) to reset the relay.
Chapter 1 - Page 34 of 38
The data storage menu contains the settings for the Waveform and Fault storage
© 2022 Siemens Protection Devices Limited
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