LINE SECTIONALIZING USING A PLC AND ABB PROTECTIVE RELAY
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Figure 39. Segment 3 Network 10 – Resume Cyclic XMIT Poll Logic
Segment 3 Networks 11 through 20
As illustrated in Figure 31 – The first 10 instructions in the buffer are to read data from the Modbus
registers in the DPU or PCD and stack them in the PLC for later data processing to perform the load
shedding/load restoration (line sectionalizing). Figure 31 illustrates in the FILE 2 explanation, that
whenever the POINTER from number 1 to 10 is placed in the FIFO (if an interrupt command is required)
or if the UCTR instruction in Segment 3 Network2 changed within it’s sequence, the data is transferred as
illustrated. Networks 11 through 20 perform the following:
•
If the SUB and FIN combination logic construct is energized by the preceding contact, the
FIFO is filled with the queue’d command for processing by the XMIT block. This stops the
cyclic polling (if occurring) and schedules the command for execution in the next 100 mS.
•
When the XMIT block executes and receives the successful transmission, the data received
is transferred from the XMIT block buffer and transmitted to the PLC data storage buffer
41750 through 41850. The data may be viewed by an operator interface such as MAGELIS,
stored for further processing (decisions on whether to perform the line sectionalizing), or
stored in other memory areas for data buffering/concentration for transfer to a host device at
a later date.
The contact to the left of the rail (1
st
logic construct) are those which schedule the XMIT transmission.
Figures 40 through 49 illustrate the data FIFO instruction queue initiation and the data storage
mechanism.
Summary of Contents for REL 356
Page 23: ...ABB REL 356 Current Differential Protection 1 10 Product Overview and Specifications ...
Page 83: ...ABB REL 356 Current Differential Protection 3 36 Settings and Application ...
Page 127: ...ABB REL 356 Current Differential Protection 5 28 Testing ...
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