[time-nuts] Do any regulations or laws require time tobeaccurate within 'x' seconds?
Tom Van Baak
tvb at LeapSecond.com
Fri Nov 21 20:42:16 UTC 2008
It would appear these documents are just talking about annual
calibration requirements of the *transducer* (the control room
test equipment used to measure line frequency) and do not
imply a specification of line frequency itself.
Does anyone know which NERC document specifies power line
phase or frequency? (and note that a frequency measurement
implies an averaging time).
See http://leapsecond.com/pages/mains/ for the ADEV of power
line frequency. It's ~2e-5 at one day. So does NERC owe me a
million bucks or not?
----- Original Message -----
From: "Bill Hawkins" <bill at iaxs.net>
To: "'Discussion of precise time and frequency measurement'" <time-nuts at febo.com>
Sent: Friday, November 21, 2008 12:16 PM
Subject: Re: [time-nuts] Do any regulations or laws require time tobeaccurate within 'x' seconds?
> That's an interesting reference. Google finds it.
> Assuming that the digital frequency transducer measures the 60 Hz line
> frequency, the required accuracy is somewhat less than 2 parts in 10E-5.
> Analog transducers, like Watts, Volts, and VARs, require 0.25% of scale
> accuracy. Calibration is annual.
> This is nothing like the 10E-15 sought by time nuts.
> Bill Hawkins
> -----Original Message-----
> From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
> Behalf Of Mike Clapp
> Sent: Friday, November 21, 2008 1:04 PM
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] Do any regulations or laws require time to
> beaccurate within 'x' seconds?
> The North American Electric Reliability Corporation (NERC) under federal
> law can fine of up to $1 million a day.
> Standard BAL-005-0 - Automatic Generation Control Requirement 17. Each
> Balancing Authority shall at least annually check and calibrate its time
> error and frequency devices against a common reference. The Balancing
> Authority shall adhere to the minimum values for measuring devices as
> listed below:
> Device Accuracy
> Digital frequency transducer ? 0.001 Hz
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