Transfer Of Differential Current Values; The Delta/Dead Band Algorithm - ABB REB500 Communication Protocol Manual

Section 2
Interbay bus functions
2.4
2.4.1
8
Diagnostic and system events are always available for transfer whichever protocol
is in use and cannot be configured.
The IEC 60870-5-103 section only appears when the protocol is configured.

Transfer of differential current values

The delta/dead band algorithm

To keep the load on the IBB as low as possible, the bus zone differential currents
are checked cyclically, but only actually transferred via the bus if the value has
changed.
Figure 5 Transmitted values and the zero limit
To stabilize the display during normal operation, differential currents below the
zero limit (dead band) count as zero and are transferred as such.
Providing the condition for transmitting a current value is fulfilled, all the
differential currents belonging to the respective zone are sent to the SCS/SMS.
sum = sum + |current – last|
if sum > delta then
sum = 0
if current < deadband then
current = 0
endif
send current
endif
last = current
Communication Protocol Manual, IEC 60870-5-103
Distributed busbar protection REB500
1MRK 511 371-UEN