ABB Relion 650 Series Technical Manual page 474

Section 13
Monitoring
13.11.5 Operation principle
Disturbance recording is based on the acquisition of binary and analog signals. The binary signals
can be either true binary input signals or internal logical signals generated by the functions in the
IED. The analog signals to be recorded are input channels from the Transformer Input Module
(TRM) through the Signal Matrix Analog Input (SMAI) and possible summation (Sum3Ph) function
blocks and some internally derived analog signals.
Disturbance recorder collects analog values and binary signals continuously, in a cyclic buffer. The
pre-fault buffer operates according to the FIFO principle; old data will continuously be overwritten
as new data arrives when the buffer is full. The size of this buffer is determined by the set pre-fault
recording time.
Upon detection of a fault condition (triggering), the disturbance is time tagged and the data
storage continues in a post-fault buffer. The storage process continues as long as the fault
condition prevails - plus a certain additional time. This is called the post-fault time and it can be
set in the disturbance report.
The above mentioned two parts form a disturbance recording. The whole memory, intended for
disturbance recordings, acts as a cyclic buffer and when it is full, the oldest recording is
overwritten. The last 100 recordings are stored in the IED.
The time tagging refers to the activation of the trigger that starts the disturbance recording. A
recording can be trigged by, manual start, binary input and/or from analog inputs (over-/
underlevel trig).
A user-defined name for each of the signals can be set. These names are common for all functions
within the disturbance report functionality.
13.11.5.1 Memory and storage
When a recording is completed, a post recording processing occurs.
This post-recording processing comprises:
• Saving the data for analog channels with corresponding data for binary signals
• Add relevant data to be used by the Disturbance handling tool (part of PCM 600)
• Compression of the data, which is performed without losing any data accuracy
• Storing the compressed data in a non-volatile memory (flash memory)
The recorded disturbance is now ready for retrieval and evaluation.
The recording files comply with the Comtrade standard IEC 60255-24 and are divided into three
files; a header file (HDR), a configuration file (CFG) and a data file (DAT).
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The maximum number of recordings depend on each recordings total recording
time. Long recording time will reduce the number of recordings to less than 100.
The IED flash disk should NOT be used to store any user files. This might cause
disturbance recordings to be deleted due to lack of disk space.
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Line distance protection REL650
Technical manual