I log the AC mains voltage at my house starting July 2013, you may recall my post where I was concerned about the unusually high voltage readings at home. Now that I have few months of data collected, it is time to do some analysis. I have 405835 measurements in total since then, taken every 10 seconds. I am logging these to emoncms, then exported as CSV and used Tableau Public to generate the below analysis.
Voltage (and frequency) varies with the load of the grid, lower voltage indicates higher consumption in the segment where I am connected and higher voltage means the opposite, i.e. grid is experiencing relatively low load.
I started with an analysis of voltage by day of the the week and then colored by the quarter of the year, Q4 is when the heating season starts so there is obviously a difference. Wednesdays in Q3 Thursdays in Q4 are the outliers here, I wonder why. Weekends on the other side seem relatively unaffected by the season, probably this has to do with commercial usage.