[time-nuts] power grid timing

[Ruslan Nabioullin]

I encountered an interesting presentation from NIST, ``GPS Time Backup
for Power Industry''
(https://www.naspi.org/sites/default/files/2017-03/nist_lowe_gps_time_backup_power_industry_20170322.pdf)
(supposedly from '17) on a proposed GPS fallback solution (Radio KNIT)
based on WWVB---problem is, it might rely upon the Internet (rather
than a hardened internet)...  Anyway, although I'm sure that there's
much more detailed information out there regarding timing
requirements, one of the slides was interesting---``Power Grid
Application Timing Needs'':

``
---------------------------------------------------------------------------------------------------------------------------
Application
                                        |         Need
---------------------------------------------------------------------------------------------------------------------------
General Purpose
                                  |         < ±100 ms

                                              |
Time-Stamping SCADA and Operational Data Logs
          |         < ±1 ms

                                              |
Substation Monitoring e.g. phasor measurement units (PMUs)                   |
(IRIG-B Replacement Applications with a local PTP grandmaster )
     |        < ±1 μs

                                               |
Extended distance applications
                            |
(fault detection, transient suppression)
                           |       < ±1 μs
---------------------------------------------------------------------------------------------------------------------------
''

So the first two can be satisfied with WWV/WWVH and/or WWVB alone,
though I'm not sure what degree of functionality ``General Purpose''
entails...  Obviously systems can theoretically incorporate graceful
degradation functionality w.r.t. T&F reference.

-Ruslan

-- 
Ruslan Nabioullin
Wittgenstein Laboratories
rnabioullin at gmail.com
(508) 523-8535
50 Louise Dr.
Hollis, NH 03049