269   PTRC and Switch on to fault

Created: 08 Dec 2005

Status: In Force (green)

Part: Part 7-4 (2003)


Page: 30

Clause: 5.4.21


Category: Issue for edition 2 of this part


If an open circuit breaker is closed, it may switch on to a fault, e.g. if a mobile earth connection for maintenance is connected or any other permanent fault exist which has happened on the disconnected part of the line, busbar or cable. In this case, any related protection function has operate/trip immediately without any time delay. There is no LN in the standard (7-4) defined for this functionality.


Both the Str (start) and the Op (operate) of all connected protection LNs are available (subscribed)in the related PTRC. Normally the Tr (trip) is issued by PTRC based on a logical OR of all the Op's including all the individual delays of the protection functions. In case of "Switch on to fault" a logical OR of all Str's shall issue the Tr (trip). The "switch on to fault" situation may be simply defined if the breaker was longer open then a predefined time:

Discussion Created Status
No additional comments within the ballot period. Final proposal accepted. 13 Jul 06 In Force (green)
There will a dedicated LN RSOF wich will handle all this functionality using the setting MinOpnTmms (ING) and creating an output "Op" (SPS). This can be used also as input for PTRC. 08 Jun 06 Ballot Period
For the following reasons, I come back to my proposal (to be discussed and decided in Nürnberg, June 2006)
1) We cannot wait for this very import functionality on the results of IEEE H5.
2) Second, we have to discuss for Ed 2 if and what settings will be declared as mandatory.
3) Since the trip on to fault logics is not a dedicated function but only a different connection between st, op and tr of exisitng protection functions, it fits eactly to the marshalling capability of PTRC intended from the beginning. The only difference is that in this case the marshalling is dynamically dependent on a time supervised external condition.
4)If we introduce in PTRC this addtional time setting MinOpnTmms (CDC=ING)as optional we create no conflict neither with backward compatibility nor with some future findings of IEEE H5
14 May 06 Discussion (red)
It seems that this parameter describes more of functionality of the PTRC. Maybe it changes the scope of the function of the LN. I don't know if we should do so.
The other thing is that we should wait the results of the IEEE working group (standardization of settings in IEC61850). There is no need to fix further settings than we have in the standard up to now. They can be private.
So I don't agree now, but see the need in the future.
12 Jan 06 Discussion (red)
Sorry, the time definition was missing in the proposal: The predefined time should be added to PTRC

MinOpnTmms (ING) Minimum Breaker Open Time for Switch on to Fault
08 Dec 05 Triage


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