Disturbance Recorder - GE MiCOM P747 Agile Technical Manual

MiCOM P747 Chapter 6 - Monitoring and Control
3

DISTURBANCE RECORDER

The disturbance recorder feature allows you to record selected current and voltage inputs to the protection
elements, together with selected digital signals. The digital signals may be inputs, outputs, or internal DDB
signals. The disturbance records can be extracted using the disturbance record viewer in the settings
application software. The disturbance record file can also be stored in the COMTRADE format. This allows
the use of other packages to view the recorded data.
The integral disturbance recorder has an area of memory specifically set aside for storing disturbance
records. The number of records that can be stored is dependent on the recording duration. The minimum
duration is 0.1 s and the maximum duration is 10.5 s.
When the available memory is exhausted, the oldest records are overwritten by the newest ones.
Each disturbance record consists of a number of analogue data channels and digital data channels. The
relevant CT and VT ratios for the analogue channels are also extracted to enable scaling to primary
quantities.
The fault recording times are set by a combination of the Duration and Trigger Position cells. The Duration
cell sets the overall recording time and the Trigger Position cell sets the trigger point as a percentage of the
duration. For example, the default settings show that the overall recording time is set to 1.5 s with the trigger
point being at 33.3% of this, giving 0.5 s pre-fault and 1 s post fault recording times.
With the Trigger Mode set to Single, if further triggers occurs whilst a recording is taking place, the
recorder will ignore the trigger. However, with the Trigger Mode set to Extended, the post trigger timer will
be reset to zero, extending the recording time.
You can select any of the IED's analogue inputs as analogue channels to be recorded. You can also map
any of the opto-inputs output contacts to the digital channels. In addition, you may also map a number of
DDB signals such as Starts and LEDs to digital channels.
You may choose any of the digital channels to trigger the disturbance recorder on either a low to high or a
high to low transition, via the Input Trigger cell. The default settings are such that any dedicated trip output
contacts will trigger the recorder.
It is not possible to view the disturbance records locally via the front panel LCD. You must extract these
using suitable setting application software such as MiCOM S1 Agile.
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