1141   Issue in mapping IEEE.118.C37 time quality to MMS UTC time Quality

Created: 21 Jul 2013

Status: Not Applicable

Part: Part 90-5 (2013; Edition 1, Synchrophasor)

Links:

Page: 69

Clause: 11.3.1.1

Paragraph:

Category: Issue for edition 2 of this part

Issue

RefrTm is the time stamp attribute that is defined by 61850 90-5 which can be used to map C37.118 time stamp. In C37.118 Time Stamp is a 64 bit value, consisting of a 4-byte second-of-century (SOC) and 4-byte FRACSEC, which includes a 24-bit FRACSEC integer and an 8-bit Time Quality flag. It is similar to 61850 TimeStamp attribute type . The "Seconds" part can be mapped directly but the time quality explanation of C37 is different from IEC61850. In C37.118 Time quality there are separate bits to represent Leap second Direction, Leap second Occurred and Leap second Pending, where in IEC 61850 Time quality we have only Leap second Known.

Proposal

An explanation on how to map C37.118 time stamp to 61850 time stamp will be nice to avoid confusion or an addition of new time stamp format can be considered.