When the local / remote model for IEC 61850 has been designed, it was discussed to use it for primary equipment (i.e. data local of LN XSWI) and for IEDs (i.e. data local of LN CSWI). At IED level it means that the data Loc of CSWI typically reflects the position of a key-switch at the IED. If the switch is set to local, all CSWI.Loc are TRUE and no operation from outside the IED (i.e. no operation through a client) is accepted.
With regard to higher hierarchical levels (i.e. local/remote for the complete substation), it was decided that this shall be handled between the different clients. However, the standard does not define, how it shall be handled.
With the use of IEC 61850 as well for the connection to the control center, that is an issue that needs to be further clarified more general.
A typical application already relevant today (independent of the use of 61850 to the control center) is the local/remote switch of a complete substation. If an operator is working in the substation, it may switch the substation to local and not accept remote control anymore.
The local / remote switch for the complete substation can be considered as an input to the substation gateway. The substation gateway is the client for remote operation of the substation. If the switch is in local, no operation request will be issued.
This alone is not necessarily requiring standardization. But it might be required, that the information about the switch position is also used in other devices of the substation (i.e. in the local operator workplace). Therefore, I would propose to add the data object Loc to the logical node ITCI and maybe as well to IHMI.
05 Apr 07
In Force (green)
Decided in San Diego by WG10 the data model should be as following:
LocKey SPS Key Local operation O
RemCtlBlk SPC Remote Control Blocked O
Loc SPS Local Control Behavior O
For backward compatibility the DO "Loc" (ed.1) will be renamed to LocKey (ed.2).
23 Mar 07
Additionally to data Loc include in Common Logical Node the following data:
RemCtlBlk CDC: SPC Remote Control Blocked Optional
LocCtlBeh CDC: SPS Local Control Behavior Optional
with the logic:
Regarding multiple remote it is proposed to evaluate the originator (orCat, orIdent).
13 Dec 06
According to discussion at Nuremberg this should be solved as follows: Leave the Loc as is (also for backwards compatibility), however declare it explicitly as 'resulting Local/remote behavior at this LN (resp LD, if in LN0)'. Add another DATA LocMod: INC (values: process, bay, station, NCC) which shows e.g. the state of a physical switch for a whole bay or station, and could allow to set the local mode at the LN / LD where it is supplied, as follows: e.g. 'bay' means, commands up to bay level are accepted, higher levels are refused; within a hierachy of LocMods the lowest value at a level determines the Loc result at this level (similar to Mod/Beh). The setting might be restricted (e.g. Bay/station at bay level. Observe that the Loc at interfacing LNs (X..., Y...) refers to LocMod process, those at CSWI and ATCC to LocMod bay, and those in LDs from bay (common) and higher levels.
07 Jul 06
I agree that the issue can be solved using the Loc of LN0. But the question is then, why do we have (and use?) the Loc of CSWI and XCBR. Both of these logical nodes are in logical devices as well. And at least for the CSWI, we typically have on switch at the IED that has the bay control functionality. We could as well there use Loc of the LN0.
The LNs involved in the operation chain are ITCI or IHMI - CSWI - XCBR. I think, they should be treated smilar. So I would still maintain my proposal to add Loc to the IHMI and ITCI node.
15 May 06
The DATA Loc is already available in LN0. Therefore it isno necessary to have it in ITCI or IHMI or whatever, just within LN0 of the logical device representing the HMI (where it would logically belong, if it has a server) or the gateway. In general, each switch yard part to be managed by some NCC could be allocated to some logical device, allocated somewhere, to switch it from (station) local to (NCC) remote. Therefore no change of standard is necessary, however may be a user guide or some informative example in 7-4.