Areva MiCOM P441, Technical Manual

Page: 345 / 636

Application Notes P44x/EN AP/E33
MiCOM P441/P442 & P444 Page 171/220
FIGURE 120
4.10 Disturbance recorder
The integral disturbance recorder has an area of memory specifically set aside for record
storage. The number of records that may be stored is dependent upon the selected
recording duration but the relays typically have the capability of storing a minimum of 20
records, each of 10.5 second duration.
NOTE: 1. Compressed Disturbance Recorder used for Kbus/Modbus/DNP3
reach that typical size value (10.5 sec duration)
2. Uncompressed Disturbance Recorder used for IEC 60870-5/103
could be limited to 2 or 3 secondes.
Disturbance records continue to be recorded until the available memory is exhausted, at
which time the oldest record(s) are overwritten to make space for the newest one.
The recorder stores actual samples which are taken at a rate of 24 samples per cycle.
Each disturbance record consists of eight analogue data channels and thirty-two digital data
channels. Note that the relevant CT and VT ratios for the analogue channels are also
extracted to enable scaling to primary quantities).