1396   The use and configuration flow of LGOS and LSVS is Unclear

Created: 03 Jun 2015

Status: In Force (green)

Part: Part 7-1 (2011; Edition 2)

Links: #1401 Supervision of GOOSE/SV capabilities

Page:

Clause:

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Category: Issue for edition 2 of this part

Issue

Currently, there is no defined methodology to manage/configure LGOS and LSVS in an interoperable fashion. As an example, it is unclear if there needs to be a LGOS for every GOOSE subscription and how the binding between the subscription and LGOS instance that is supervising the subscription.

Proposal

From the User Feedback Taskforce (Regina June 2015):

1). For IEDs, each GOOSE/SV subscription, there shall be one LGOS or LSVS provided. If the IEDs that have only ClientServices, then there need not be an instantiation of LGOs or LSVS.

2). For IEDs that have supervision capabilities, the ICD shall contain at least one installation (e.g. LNInst) of that supervision function. It shall not provide instances that number more than the maximum number of subscriptions declared in the Service Capabilities.

3). If the number of configured subscriptions exceeds the number of supervision Logical Nodes, then the SCD needs to be provided to the appropriate ICT. The exported IID shall contain, as a minimum, the number of supervision logical nodes that match the number of descriptions.

4). If # of supervision logical nodes (e.g. LGOS) = # of subscriptions (e.g. GOOSE subscription) required by the design (in the SCD),
- If valImport = TRUE, the SCT can configure the reference between the LGOS and the GCB
- If valImport = FALSE, a round trip is needed between ICT and SCT. The ICT shall then assign/configure the supervision logical nodes.

5). If # of supervision (e.g. LGOS) is larger than # of subscription (e.g. GOOSE subscriptions) required by the design (in the SCD), and the SCT could assign the LGOS to subscribed GCB, the ICT may delete the remaining LGOS (and update the SCT trough roundtrip).

6). If # of LGOS larger or equal to # of GOOSE subscription required by the design (in the SCD), and the SCT did not assign the LGOS to subscribed GCB, the ICT assigns the LGOS to GCB and may delete the unused LGOS (and update the SCT trough roundtrip).

7). If a round trip is needed, once the ICT has configured relations between a LGOS and a GCB, and later a GOOSE susbscription is deleted, ICT may not reconfigure the already existing relations between LGOS and GCB (e.g. we have LGOS1 and LGOS2 configured to two GOOSE susbcriptions, if later the first GOOSE subscription is deleted, the second one must remain associated to LGOS2). However, if later a new subscription is added, it may reuse LGOS1.

NOTE: if a LGOS has no GCB associated (reference = empty string), that means that this LGOS is not active. This can be further generalized: whenever we have an ORG data object with an empty string it means that there is no object referenced.





Discussion Created Status
14 Aug 15 In Force (green)
The usage of the SupSubcription element will be enhanced as follows:
If an IED supports LGOS/LSVS creation of an IED (SubSupscription has maxGo>0 or maxSv>0), it shall provide at least one instance of this. The SCT is then allowed to create more instances with increasing LN inst number and exactly the same LNodeType inside the same LDevice up to the specified limit. If the number of the limit is already reached or no SupSubscription element given, no LGOS/LSVS instance can be created by the SCT.
16 Jul 15 Ballot Period
This is not ineffective configuration to expect the ICT to be responsible for instantiation of the IED data model even for the supervision objects.
Round trip engineering is common practise as the SCD is the documentation of the projects and needs to be updated according to the real device configuration (settings, cf, ...).
Instanciating the instances of the LGOS/LSVS in the SCT should be tied to a LNodeType that may not be present in the DataTypeTemplate of the ICD/IID file as long as not a single supervision LN is provided by the ICT.
At least the capabilities of supervision should be tied to linking the LNodeType to the capability so that the SCD file is complete and consistent.
07 Jul 15 Discussion (red)
This is one possible way to handle GOOSE / SV supervision configuration, however an ineffective one as it needs a lot of round trip engineering between system tool and IED tool, and is vulnerable against later modifications of the data flow. It is however supported by the SCL definition possibilities. A more effective one is currently also supported by part 6 (SCL): the IED tells the maximum number of LGOS instances it can make visible, and the SCT configures those it needs for the system.
Finally, the GoCBRef / SvCBRef data objects are settings, whose value could be dynamically changed redirecting the supervision to another source CB. Thus with one LGOS instance all received GOOSE can be supervised, one after the other. This needs an appropriate supervision client function, however no additional configuration effort in IED or system tool.
It is up to the IED manufacturer to decide how he wants to implement this. Therefore, this might belong into some engineering guide, but not into the standard.
09 Jun 15 Discussion (red)

 

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