Diff.
Current
Values transferred
to the SCS
Zero limit
0
100
200
12000189-IEC18000308-1-en.vsd
IEC18000308 V1 EN-US
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.
Example 1
sum = sum + |current – last|
if sum > delta then
sum = 0
if current < deadband then
current = 0
endif
send current
endif
last = current
The system continuously performs the above algorithm: It adds up the absolute difference
between the last two measurements (current and last) since the last status update was sent
(sum).
As soon as sum is greater than the threshold delta a new event will be sent with the current
value. If this value is below the deadband threshold, the value 0 will be sent instead.
3.4.2
Configuring the SCS differential current parameter
GUID-DF29CA42-6DDD-459D-A610-175B597D83C9 v2
The precise conditions for sending differential currents to the SCS can be set by selecting
HMI500 Settings/Communication/SCS Diff. Current Parameters.
1MRK 511 451-UEN Rev. C
Section 3
Interbay bus functions
Distributed busbar protection REB500
11
Communication protocol manual IEC 60870-5-103
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