HI > On Feb 27, 2015, at 10:46 AM, Philip Gladstone > <[email protected]> wrote: > > On 2/26/15 20:39, Charles Steinmetz wrote: >> ben wrote: >> >>> I'm going to have to build one of these. Assume you have some sort of >>> circuit that converts low-voltage AC from a transformer secondary to >>> a pulse train, start a timer, and count x amount of pulses? >> >> Here is a zero-cross detector designed for this purpose: >> >> <http://www.ko4bb.com/manuals/download.php?file=02_GPS_Timing/Simple_AC_Mains_Zero_Crossing_Detector.pdf> >> >> >> Most mains-nuts feed the ZCD pulse to the DCD line of a PC's RS232 >> port and use the computer to time-stamp the crossings and append them >> to a file of such time stamps. > If we all did this, then I realize that we could identify the different power > grids. However, I wonder if there is any interesting variation *within* a > grid. As the electricity flows vary throughout the day, it seems possible > that the phase difference between two people on the same grid would actually > change (a bit). > > Has anybody done this experiment?
It’s done by utilities to monitor power flow and balance electric grids. The first data on this (grid vs GPS) date to the 1980’s. I think the paper I recall was done by Quebec Hydro. Since then it’s become a pretty standard monitoring tool. Bob > > Philip > _______________________________________________ > 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.
