281   LN RPSB

Created: 12 Jan 2006

Status: In Force (green)

Part: Part 7-4 (2003)

Links:

Page: 40

Clause: 5.5.9

Paragraph:

Category: Issue for edition 2 of this part

Issue

I do not understand the aim of creating instances of LN RPSB with the same instance numbers as PDIS per zone. Normally, distance relays include a power swing detector which is common for all the zones and which generates a blocking signal which can be used for any of the zones. All the settings and signals that come from that power swing detector would be the same for all the distance zones. On the other hand, "out of step tripping" signal often has not to do with the distance zones (it is the out of step detector which trips, not the distance zones, which remain blocked). Is it possible to define only one RPSB (without instances) with "BlkZn" data as a common blocking signal for all the zones?.

Other thing I would like to clarify is with regard to data Str in status information, which CDC is ACD type. "General" attribute in ACD is defined as an "or" of the phase values, however "power swing detected" signal could be an "and" or "2 out of 3" of the phase values (in case power swing detection is done per phase). Is still possible to use "general" attribute with those meanings?.

Proposal