There have been a number of proposals to completely eliminate manual time correction (used to keep synchronous clocks accurate over long time periods). There apparently was a manual procedure activated when the error reached +/- 30 seconds from true time, but I think that since 2011 the power grid reliability considerations have caused grid operators to not make any frequency changes for clock time correction. Frequency changes are often made to change the power transfer rate.
See: FERC Docket RM14-10-000 Order: Real Power Balancing Control Performance Reliability Standard (issued April 16, 2015) - this doesn't mention use of time error correction! http://www.ferc.gov/whats-new/comm-meet/2015/041615/E-3.PDF FERC docket RM09-13-000: Time Error Correction Reliability Standard http://www.balch.com/files/upload/%284-24-2010%29%20NERC_BAL-004_NOPR_Comments.pdf In October 2012 this petition was withdrawn. 60Hz Stability on Power Grid Going Away? http://www.radiomagonline.com/deep-dig/0005/60hz-stability-on-power-grid-going-away/33527 NERC Frequency Response Standard Background Document http://www.nerc.com/comm/oc/rs%20landing%20page%20dl/related%20files/bal-003-1_background_document_clean_20121130.pdf It appears from various comments that with no manual time correction, the accumulated time error in the East Interconnection will typically gain 20+ minutes/year. The West will gain 8 minutes/year and ERCOT (Texas area) will gain 2 minutes/year. http://www.ercot.com/content/meetings/rms/keydocs/2011/0518/03_manual_time_error_correction_elimination_field_trial.doc So don't trust an AC synchronous motor clock in North America. -- Bill Byrom N5BB On Sun, Jul 26, 2015, at 07:08 AM, Bob Camp wrote: > Hi > > That correlates quite well with data from the 1960’s before “everybody” > was > on one big network. > > Bob > >> On Jul 25, 2015, at 7:25 PM, Hal Murray <[email protected]> wrote: >> >> >> I've updated the graph at: >> http://www.megapathdsl.net/~hmurray/time-nuts/line/Calif-60Hz-2014-2015.pn >> g >> >> and added July-2015 at: >> http://www.megapathdsl.net/~hmurray/time-nuts/line/Calif-60Hz-2015-Jul.png >> >> July 19th shifted 15 seconds in one day! >> The shift is 25 seconds over July 17-19. >> >> -- >> These are my opinions. I hate spam. >> >> >> >> _________________________________________________ >> time-nuts mailing list -- [email protected] >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. > > _________________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
