For private usage: correct. They are for backwards compatibility and standard internal usage, not for private definitions.
01 Jul 14
In Force (green)
When it is not allowed in Ed.2 to extend with private CDC -> the DA cdcNs and cdcName of part 7-3 are obsolete
23 Apr 14
In Force (green)
Not accepted, as the Ed2 normative schema only allows Ed2 defined CDCs.
27 Feb 14
In Force (green)
Note that the Ed2 normative schema is valid for Ed2 IEDs, which are only allowed to use the defined Ed2 CDCs. Inside a system also IEDs from other editions may reside, therefore this restriction is NOT valid as input for a system tool respective a produced SCD file with IEDs from other editions.
21 Nov 13
Discussion (red)
In Ed. 2, private CDCs are not allowed anymore. Thus only the predefined CDCs are accepted. Thus the proposal shall be rejected.
BTW, in the informative SCL schema (version 2.1 or "Mixed.2007B") extensions are allowed.