Do you all still see or use controls that employ synchronous clocks/timers that rely on a 60Hz pulse from the grid?
Are they still accurate?
Did you know grid does not keep a perfect 60hz without help?
Without adjustments timers and clocks drift. During the morning load "ramp-up," the grid usually runs slightly slow (around ~59.97 Hz). In the middle of the night, when demand is low, it often runs slightly fast to make up for lost 'time' (~60.03 Hz).
Grid operators are or were legally required to correct at night to "pay back" those lost cycles, I am no expert on it but I have been told without it a mechanical clock could be off by 20 - 60 seconds in a single day, granted thats not every day probably only 10-20 minutes per year.
Here on the Western Grid its called Automatic Time Error Correction (ATEC) if the frequency dipped during the day due to heavy load, they would automatically run it slightly fast at night to "catch up" so that over 24 hours, the total number of cycles was exactly 60×60×24×60=5,184,000.
However with new forms of generation like PV these adjustments are apparently growing and annoying utilities, they say its outdated, and they are lobbying to eliminate the requirement.
So for the last 5- 6 years the North American Energy Standards Board (NAESB) has been trying to get rid if this, and they have losened the rules around it.
One of the arguments for keeping it is that many industrial processes still use electro-mechanical timers, possibly critical processes.
So I am curious how many of you controls people out there have equipment or processes in the field that need accurate elctro-mechanical timers? or use the grid for accurate time?
Are they still accurate?
Did you know grid does not keep a perfect 60hz without help?
Without adjustments timers and clocks drift. During the morning load "ramp-up," the grid usually runs slightly slow (around ~59.97 Hz). In the middle of the night, when demand is low, it often runs slightly fast to make up for lost 'time' (~60.03 Hz).
Grid operators are or were legally required to correct at night to "pay back" those lost cycles, I am no expert on it but I have been told without it a mechanical clock could be off by 20 - 60 seconds in a single day, granted thats not every day probably only 10-20 minutes per year.
Here on the Western Grid its called Automatic Time Error Correction (ATEC) if the frequency dipped during the day due to heavy load, they would automatically run it slightly fast at night to "catch up" so that over 24 hours, the total number of cycles was exactly 60×60×24×60=5,184,000.
However with new forms of generation like PV these adjustments are apparently growing and annoying utilities, they say its outdated, and they are lobbying to eliminate the requirement.
So for the last 5- 6 years the North American Energy Standards Board (NAESB) has been trying to get rid if this, and they have losened the rules around it.
One of the arguments for keeping it is that many industrial processes still use electro-mechanical timers, possibly critical processes.
So I am curious how many of you controls people out there have equipment or processes in the field that need accurate elctro-mechanical timers? or use the grid for accurate time?
