[LEAPSECS] Time Error Correction "Field Test"

[Jonathan E. Hardis]

A note for you horologists in the U.S....

Beginning in about a month (approx. July 14), the electric power  
industry will stop making "Time Error Corrections" on the U.S. power  
grid.  For those timekeeping devices that rely on 60 Hz power as their  
frequency reference, based on past experience those in the Eastern  
U.S. will gain time at a rate approximately 20 minutes/year, those in  
the Western U.S. will gain time at a rate approximately 8 minutes/ 
year, and those on the Texas interconnect will gain time at a rate  
approximately 2 minutes/year.

While the AC power frequency in the U.S. is nominally 60 Hz, left to  
its own devices the grid tends to run fast, at a frequency slightly  
greater than 60 Hz.  Since the 1930's, when the Telechron clock was  
introduced, the electric power industry has made an effort to ensure  
that the power frequency was 60 Hz on average by deliberately running  
slow to compensate for periods of running fast.  Today, the grid is  
operated at a target frequency of 59.98 Hz in a procedure called "Time  
Error Correction" to maintain the 60 Hz average.  However, beginning  
next month, the industry plans to stop making Time Error Corrections  
in a "field test."  The test is planned to last a year and to cover  
the entire contiguous U.S.

The electric power industry petitioned the Federal Energy Regulatory  
Commission (FERC) for a rules change that would make the industry's  
prerogative to end Time Error Correction unambiguous. That petition is  
currently in limbo. If the field test is successful -- however  
"successful" might be defined -- you can expect the industry to press  
their case again at FERC.

For additional information, please see:

1)  The filings at FERC.  Starting at http://elibrary.ferc.gov/idmws/docket_search.asp 
   search for all filings on Docket Number RM09-13 ,
2)  The information on the field test.
      http://www.nerc.com/page.php?cid=6|386
      http://www.nerc.com/files/NERC_TEC_Field_Trial_Webinar_061411.pdf


    - Jonathan