Interoperability - can it be achieved?
Dennis Holstein, Publisher
December 2001
It is an immutable law in business that words are
words, explanations are explanations, promises are promises -- but only
performance is reality.
Harold S. Green
Now lets look at IEC 61850
Part
7 of IEC 61850 is an abstract model of information to be exchanged between intelligent
electronic devices - lots of words, lots of explanations, and a promise of
interoperability. However, its implementation requires a mapping to a service
provider. This service provider is specified in Part 8-1 of IEC 61850, which specifically maps to
the old version of MMS (ISO 9506, version 1).
IEC 61850-8-1 includes the following paragraph in clause 2 - Normative
references:
The following normative documents contain
provisions which, through reference in this text, constitute provisions of this
part of IEC 61850. For dated references, subsequent amendments to, or revisions
of, any of these publications do not apply. However, parties to agreements based
on this part of IEC 61850 are encouraged to investigate the possibility of
applying the most recent editions of the normative documents indicated below.
[Note: It is intentional to reference version 1 of ISO 9506. There are no
current plans to migrate this standard to the use of the 2000 version (version
2) of ISO 9506.]
Interoperability
has been the "holy grail" of IEC 61850. Advocates of IEC 61850 have
been paranoid about any technical concepts that do not achieve interoperability.
Their
attack on IEEE P1525 has been, and still are, relentless because IEEE P1525 is an
incomplete specification and therefore cannot guarantee interoperability. Of
course this is true. IEEE P1525 only provides a framework and depends on other
companion specifications or vendor/utility agreements to achieve
interoperability.
But
now, the truth is beginning to show through. Interoperability can only be realized
in IEC 61850 if an obsolete specification for MMS imposed. Vendors that implement the most
recent version of MMS in their IEDs will not interoperate with IEDs that do not
include these features, and by definition will be non-conformant to IEC 61850.
Some examples are:
Furthermore, it is not clear in IEC 61850-8-1 how
version control is to implemented, which seriously exacerbates the issue.
In
the opinion of this old wise owl, interoperability is a goal -- it is not an
absolute requirement. Given the rapidly changing communication technology and
enabling hardware, forcing complete interoperability will build obsolescence into the
implemented products.
Now
its your turn to sound off. Send an Email with your opinion to holsteindk@aol.com.
WiseOwl™