This tissue has following status: on hold
Created: 24 Jul 2015
Category: Issue for edition 2 of this part
The TimeStamp data type is used to time stamp events, Synchrophasors, and SV in 61850. TimeStamp is based on UTC and thus, when a leap second occurs, there are 2 identical time stamps. In as much as an event in one IED may have happened prior to Leap Second and an event in a second IED may have occurred during the actual Leap Second, the result is that in post event analysis, the delta t between events cannot be computed. Even though there is discussion to create a new DO for Leap Second, this does NOT address the issue of time stamping in a Sequence of Events, SV, and Synchrophasor records.
Proposal: Needed: a mechanism to identify an active leap second in TimeStamp; secondary need: the ability to identify a "negative" leap second pending in TimeStamp.
Proposal: In 8-1, the Time Quality definition in Table 32 (page 54) identifies the values of 25 through 30 as "invalid". It is proposed that the value of 30 in the Time Quality value be identified as Leap Second Active; As a second proposal - to identify that the next second is going to be missing (a negative Leap Second), the TimeStamp for the next-to-missing second shall have a Time Quality value of 29. This implementation would also be used with Synchrophasors and SV as reported from the PMU or MU accordingly.