859   MMS_UTC and leap seconds

Created: 26 Jun 2012

Status: Not Applicable

Part: Part 8-1 (2004)

Links:

Page: 130

Clause: Annex F

Paragraph: Table F.2

Category: Issue for edition 2 of this part

Issue

I think that relationship between MMS_UTC in Table F.2 in IEC 61850-8-1 Ed.1 and SecondSinceEpoch in IEC 61850-7-2 Ed.1 is not clear.

I think that MMS_UTC in Table F.2 and SecondSinceEpoch is the same, and SecondSinceEpoch takes into account all or some leap seconds according to LeapSecondsKnown.

But MMS_UTC in Table F.2 contain NO leap seconds.

example (5th low in Table F.2):
UTC : 00:00:00 01.Jan 84
Leap seconds: 22
MMS_UTC : 441 763 200
= 86400 * 5113

I think that MMS_UTC above should be 441 763 222, when LeapSecondsKnown = TRUE.

Proposal

Clarify.