Monitoring of the electric grid phase in Enschede, The Netherlands
The electric grid delivers 50 Hz AC. This frequency is not precisely 50 Hz,
but changes with load and supply of energy. However, in the long term it
is kept to 50 Hz on average, so clocks (like mine)
can use it for reference.
The below graph shows the accumulated phase error of the grid, updated several times per day.
(The starting point is arbitrary, due to when I last restarted the computer doing these measurements.)
For my measurements of the 2018 grid phase anomaly, see here.
The hardware used for these measurements:
Comments are welcome at p.t.deboer@utwente.nl .