IEEE 1344

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IEEE 1344 is a standard that defines parameters for synchrophasors [1] for power systems. [2] The standard added extension to the IRIG-B time code to cover year, time quality, daylight saving time, local time offset and leap second information. IEEE 1344 was superseded by IEEE C37.118 in 2005 and the time extensions were adopted as part of the IRIG timing standard in the 2004 edition. [3]

Contents

Description

IRIG-B timecode consists of 100 bits, repeated each second. Every tenth bit is a "position identifier", and most of the remainder encode the current time (date, hour, minute and second). Bits 60–68 and 70–78 are reserved for other uses; IEEE 1344 is such a use. It defines the bits as follows:

IEEE 1344 extensions to IRIG B [4]
BitWeightMeaningBitWeightMeaning
60LSPLeap second pending at end of minute700.5Time zone offset
61LSLeap second type (0=add, 1=delete)711Time quality
(Binary, 0–15)
62DSPDST change pending at end of minute722
63DST DST in effect734
64±Time zone offset sign (0=+, 1=−)748
651Time zone offset
(0–15.5)		75PAR Even parity of bits 1−74
662760Unused
674770
688780
69P7Position identifier79P8Position identifier

The DST and leap warning bits are set no more than 59 seconds before the indicated change, and indicate the change at the end of the minute. During a leap second, the warning bit should be set, the seconds field should show "60", and the Straight Binary Seconds field should equal 60 + 60 × minutes + 3600 × hours. The next second, the leap second warning bit should be clear, and the SBS field will repeat. Since negative leap seconds have never happened, and almost certainly never will, the LS bit is always 0.

The clock quality indication is a binary value. 0 means the clock is locked to a UTC-traceable source, without specifying a particular accuracy, and 15 means the clock has failed and the time is not reliable. Values between 1 and 11 indicate the time is accurate to within 10x−10 seconds of UTC, i.e. x=1 indicates UTC±1 ns, while x=11 indicates UTC±10 s.

The time zone offset indicates the difference UTC – timecode, so UTC = timecode + offset. This value changes when DST is active. The Straight Binary Seconds field also jumps by 3600 when this happens.

The parity bit is even parity over all data bits from 1 through 74. Marker bits are ignored (or, equivalently, read as 0).

The standard also calls for indicating 2 digits of year in bits 50–58, which has been incorporated into the IRIG since 2004.

IEEE C37.118

IEEE C37.118 is designed to replace IEEE 1344. Instead of being based on IRIG and binary-coded decimals, the new standard uses a section format using ordinary binary integers. It also comes with a separate part to deal with matters such as synchophasor performance and frequency of measurement. [5]

C37.118-2005 [6] uses the opposite sign convention for time zone offset: offset = timecode − UTC, UTC = timecode − offset.

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<span class="mw-page-title-main">Leap second</span> Extra second inserted to keep civil time in sync with the Earths rotation

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<span class="mw-page-title-main">Time zone</span> Area that observes a uniform standard time

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<span class="mw-page-title-main">Vertical interval timecode</span> Type of timecode in a video signal

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<span class="mw-page-title-main">Time standard</span> Specification for measuring time

A time standard is a specification for measuring time: either the rate at which time passes or points in time or both. In modern times, several time specifications have been officially recognized as standards, where formerly they were matters of custom and practice. An example of a kind of time standard can be a time scale, specifying a method for measuring divisions of time. A standard for civil time can specify both time intervals and time-of-day.

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<span class="mw-page-title-main">SMPTE timecode</span> Standards to label individual frames of video or film with a timestamp

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<span class="mw-page-title-main">DCF77</span> German time signal radio station

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Inter-range instrumentation group timecodes, commonly known as IRIG timecode, are standard formats for transferring timing information. Atomic frequency standards and GPS receivers designed for precision timing are often equipped with an IRIG output. The standards were created by the Tele Communications Working Group of the U.S. military's Inter-Range Instrumentation Group (IRIG), the standards body of the Range Commanders Council. Work on these standards started in October 1956, and the original standards were accepted in 1960.

<span class="mw-page-title-main">Unix time</span> Date and time representation system widely used in computing

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<span class="mw-page-title-main">ALS162 time signal</span> French longwave time signal radio station

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<span class="mw-page-title-main">Phasor measurement unit</span>

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<span class="mw-page-title-main">Coordinated Universal Time</span> Primary time standard

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BSF is the callsign of the time signal transmitter owned by the National Time and Frequency Standards Laboratory of the Ministry of Economic Affairs (Taiwan), which transmits time information on 77.5 kHz in the longwave range. It was launched on May 1, 1969 and is broadcast from Zhongli District in Taichung using a T-antenna located at 25°0′20″N121°21′54″E.

References

  1. ↑ A New View of the Power System https://www.selinc.com/WorkArea/DownloadAsset.aspx?id=132 Archived 2015-04-23 at the Wayback Machine
  2. ↑ IEEE Digital Library http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=943067&isnumber=20419
  3. ↑ IRIG standard 200-04 (PDF) "Archived copy" (PDF). Archived from the original (PDF) on 2011-07-22. Retrieved 2010-08-03.{{cite web}}: CS1 maint: archived copy as title (link)
  4. ↑ IEEE Std 1344-1995 (Excerpts) (PDF), IEEE, 1995, archived from the original (PDF) on 2012-04-02, retrieved 2011-09-24
  5. ↑ Rana, Ankur Singh; Parveen, Nisha; Rasheed, Shaziya; Thomas, Mini S. (December 2015). "Exploring IEEE standard for synchrophasor C37.118 with practical implementation". 2015 Annual IEEE India Conference (INDICON). pp. 1–6. doi:10.1109/INDICON.2015.7443664. ISBN   978-1-4673-7399-9. S2CID   45765678.
  6. ↑ (Draft) Standard for Synchrophasors for Power Systems
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