tIED: removeIeds behaviours with LNodes

[danyill]

Currently I find that the behaviour of removeIED for LNodes is to replace the IED name with None when the IED is removed.

This behaviour is problematic for me when removing a number of IEDs in the Remove IEDs plugin in Transpower's distribution.

It leaves a large number of dangling LNode elements.

For various reasons we often map an LPHD node for each IED against a busbar bay.

After removing several IEDs this section looks like this:

	<Function name="BusPhysConnection">
		<LNode iedName="None" lnClass="LPHD" lnInst="0"/>
		<LNode iedName="XAT_242_C1" ldInst="CFG" lnClass="LPHD" lnInst="0"/>
		<LNode iedName="None" lnClass="LPHD" lnInst="0"/>
		<LNode iedName="None" prefix="DevID" lnClass="LPHD" lnInst="1"/>
		<LNode iedName="None" prefix="DevID" lnClass="LPHD" lnInst="1"/>
		<LNode iedName="None" lnClass="LPHD" lnInst="1"/>
		<LNode iedName="None" prefix="DevID" lnClass="LPHD" lnInst="1"/>
		<LNode iedName="None" prefix="DevID" lnClass="LPHD" lnInst="1"/>
		<LNode iedName="None" lnClass="LPHD" lnInst="1"/>
		<LNode iedName="None" lnClass="LPHD" lnInst="1"/>
		<LNode iedName="None" lnClass="LPHD" lnInst="1"/>
		<LNode iedName="None" lnClass="LPHD" lnInst="1"/>
		<LNode iedName="None" lnClass="LPHD" lnInst="0"/>
		<LNode iedName="None" lnClass="LPHD" lnInst="0"/>
		<LNode iedName="None" lnClass="LPHD" lnInst="0"/>
		<LNode iedName="None" lnClass="LPHD" lnInst="0"/>
		<LNode iedName="None" lnClass="LPHD" lnInst="0"/>
		<LNode iedName="None" lnClass="LPHD" lnInst="0"/>
	</Function>

This however becomes a schema violation:

The reason for this is spelt out in Table 8 of IEC 61850 Ed 2.1 and the subsequent text:

For specifications where iedName=”None” everywhere, the combination of the other attributes
must be unique within the same level. This means e.g. that the prefix or lnInst should be
different if several LNs with identical lnClass are used within the same substation part (i.e.
same bay). This should also be the case for IED names, if application related naming (see
8.5.4) shall be used. This is NOT checked by the SCL schema, therefore it is the
responsibility of the project engineer or system tool, if application related naming shall be
used additionally to product (IED)-related naming.

What should the behaviour of the removeIED function be here?

In my view at the least we need to provide an option to allow removal of LNodes to allow a bulk delete of IEDs without dangling, unnecessary schema non-compliance which is at least one common workflow option. I am confident it is also a valid workflow to sometimes retain the LNodes so I think it is a good case for an optional argument.

@JakobVogelsang WDYT?

Would you accept:

export type RemoveIedOptions = {
  removeLNodes: boolean;
};

function removeIED(remove: Remove, 
                   options: RemoveIedOptions = { removeLNodes: false }): (Update | Remove)[] {
 ... 
}

If you are happy with this call signature I can prepare a PR.

[JakobVogelsang]

Hi Dan, I would propose to add an option to removeLNode.

[JakobVogelsang]

Would you mind it being a default false?

[danyill]

Let's do that, I shall prepare a PR

…

On Thu, 5 Dec 2024, 21:48 Jakob Vogelsang, ***@***.***> wrote: Would you mind it being a default false? — Reply to this email directly, view it on GitHub <#121 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAFEXX5IGHC634THWQASFG32EAHNTAVCNFSM6AAAAABTB4BY22VHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZDKMJZGY2DKOBXGE> . You are receiving this because you authored the thread.Message ID: ***@***.***>

[danyill]

I think having a default of false is appropriate for an updateIED function (for a single IED). Although it could pose a problem there if there was already a iedName of None and matching other attributes.

If we had an updateIEDs function I'd use true because otherwise we would likely break schema validity (or need to check and remove as necessary) if we had multiple LNodes with matching attributes across multiple IEDs.

That posits a little challenge because the user should not see different behaviour when removing one IED vs. more than one IED. So I'd like to propose a default of true.

[JakobVogelsang]

This is very reasonable. Let's got with true then :)