Grid Frequency Experiment

[don_resqcapt19]

...
That said, tight control of grid frequency has to be maintained.

They are not going to change the tight control of the instantaneous frequency, they are just not going to correct for the cumulative effect of the small frequency changes that are a normal part of the system operation. In fact the document I linked to in post 11 says that one of the reason for eliminating the cumulative time correction is because a large number of the frequency deviations occur while the system is being run above or below 60 hertz to correct for time.

 

[DaveTap]

Slightly more seriously, how many clocks or timing devices really depend on grid frequency?

Pretty much all mechanical clocks and timers, and there are still a few electronics that divide line frequency...

 

[hurk27]

110626-1606 EDT

hurk27:

I got it from hereI have two digital clocks that obviously operate from a DC source, but get their timing information from the AC line. These do not have battery backup, and must be manually reset on power loss. These clocks are probably 40 years old.

Both my microwave oven and regular oven, 10 and 20 years old, require manual reset on power loss.

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Requiring a manual reset of the time has nothing to do with whether or not the clock has its own reference oscillator, even a battery clock will reset if the battery is remove
I agree many older line powered electronic clocks did reference the 60hz line frequency to derive the 1hz clock signal for its TTL counters, but most today use a simple 3khz crystal controlled oscillator for its reference signal, the move away from power line reference has been going on for some time because of so many stray signals being passed through the power lines causing errors, and as more and more clocks became micro controllers and incorporating battery back up had allot to do with this, I would bet that the electronic clock in your microwave is crystal controlled, mine is and it's a 1987 model, that is because of the micro-controller also has to reference this same clock signal, I have one alarm clock in my bedroom that does not even have AC to it, it has a plug in wall wart that only supplies it with 9 volts DC, and yes I can connect it to a 9 volt battery and it will function just fine, but if I disconnect it from either power supply it will revert to the uggly blinking "12:00":blink: <<< I love these new smillies

 

[hurk27]

Heres a good question that would happen in the real world for an international traveler, how many who have traveled to countries that have a different line frequency had a problem with bringing their own electronic alarm clock and it not keeping up with the time?
(of course as long as you can find the right voltage adapter which is not what I'm asking)

I would be willing to bet not many who have fairlly newer alarm clocks.

 

[gar]

110626-1953 EDT

hurk27:

I would agree that many new devices may use an internal clock, and many of those may not hold time accuracy over a long time as well as a line synced clock.

Unless you have a really high quality quartz crystal oscillator your drift per year is likely to be many seconds. Note: 1 second within a year requires stability and accuracy of 1 part in 31,557,600 using a 365.25 day year. For 1 minute accuracy you need 1 part in 525,960. You can not afford to put a good quality wristwatch crystal in an inexpensive clock. Even if clocks that run from 60 Hz power have a microprocessor internally that does not mean a highly stable or accurate oscillator is used. Thus, syncing to line frequency may be the best source of timing information for long term correctness. Line disturbances are not a reason for not using the line for timing information.

My BK 1822 frequency meter has the following specification on the time base:
Frequency 10 MHz.
Setability +/-0.1 ppm (+/-1 Hz)
Line voltage Stability Less than +/-1 ppm with a +/-10% line voltage change
Temperature stability Less than +/-0.001% (+/-10 ppm) from 0 thru 50 deg C
Maximum aging rate +/-10 ppm/year
An oven option provides +/-1 ppm for the above temperature range.

This is a far better crystal than in many low cost items.

But getting time sync infromation from NIST is probably the ideal method for many devices.

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[hurk27]

I did some searching around, and most sites that I could find on the subject claim that crystals are more accurate over power line reference, while how accurate they are today I have no idea, but I know in the last 20 to 25 years crystal have gotten very cheep as I can remember watches being sold for less then $5.00 for those cheep plastic ones, even battery wall clocks are cheep now, maybe China found away to mass produce them??? all I know if they are everywhere, I can remember buying crystals for radio use for less then $2.00 but I also know they didn't have to be accurate because of the PLL's or VCO's

Also I read about temperature compensated crystals on die being integrated into the clock chips which would also increase accuracy and reduce the cost as these can be mass produced, A TCCO can be made to achive an accuracy of 1 second a year and integrating it to on die would make it very cheep, have they been brought to the market? I have no idea.

Although that doesn't explain why two of my bedroom alarm clocks with battery back up have crystal cans on the board other then I have no idea how old they are (yard sales), one has a frequency 32.768 Hz on the can, but the other doesn't have anything on the can, (yea I broke down and took my clocks apart, but I put them back together since I have to use them for in the morning) but one is made in China the other is from Malaysia each has a 9 volt battery back up and will even sound the alarm on battery but no display on battery, I had the microwave open last week to replace a fuse that opened and I remember the crystal can right next to a clock chip as I was searching what cause the fuse to blow. (never did find a problem) although we did have lightning in the area that day, but nothing else was damaged.

I guess all this is that I don't see any big change if the power line frequency is not maintained as close as before, like I said, before this is over the media will have the sky falling, I just don't see it, another Y2K just starting!

 

[Besoeker]

Pretty much all mechanical clocks and timers,.

Doesn't mechanical mean mechanical in the sense that they are clockwork with a spring and an escapement mechanism?
i.e. mechanical as opposed to electrical....

 

[gar]

110627-0809 EDT

hurk27:

See the accuracy section of http://en.wikipedia.org/wiki/Quartz_clock .

Low cost crystals possibly 1 second per day, temperature compensated and aged maybe 10 seconds per year. 10 seconds per year is 1 second per about 36 days. That is 1 part in 3,155,760 .

Also note the relatively standard clock crystal frequency is 2^15 = 32,768 or 32.768 kHz because it is a nice binary value, 8000h, and optimizes power and size.

.

 

[Besoeker]

Heres a good question that would happen in the real world for an international traveler, how many who have traveled to countries that have a different line frequency had a problem with bringing their own electronic alarm clock and it not keeping up with the time?
(of course as long as you can find the right voltage adapter which is not what I'm asking)

I would be willing to bet not many who have fairlly newer alarm clocks.

I travel a fair bit and have done so for many years. This is including countries with different frequencies and voltages. I can't say I have ever had a problem as a result of that. Most test and measurement that needs a mains supply can work on a variety of supplies.

 

[gar]

110628-0842 EDT

From today's SME daily briefing:

Greater Grid Frequency Variation Could Save Utilities Money, Aid Renewable Usage.
Popular Science (6/28, Boyle) reports "utilities could save energy and money by allowing for greater frequency variation" in the nation's power grid, "so the Federal Energy Regulatory Commission is considering allowing the change." The article notes that variation would throw off the clocks on many appliances, which use the constant rate to keep time. "Renewable energy is one primary reason FERC cares about frequency variation," Popular Science notes, since renewable sources usually fluctuate in terms of the amount of energy they produce. "One trade group that has studied the potential effects says East Coast clocks could run 20 minutes fast over a year, and timepieces on the West Coast clocks would be off by about 8 minutes."

The AP (6/28) notes that the FERC is proposing to let the rate vary as an experiment, which "is tentatively set to start in mid-July, but that could change." Demetrios Matsakis, head of the time service department at the US Naval Observatory, said "this will be an interesting experiment to see how dependent our timekeeping is on the power grid."

I have some comments, but I am going to loose power shortly. The comments will be later.

.

 

[hurk27]

110628-0842 EDT

From today's SME daily briefing:

Greater Grid Frequency Variation Could Save Utilities Money, Aid Renewable Usage.
Popular Science (6/28, Boyle) reports "utilities could save energy and money by allowing for greater frequency variation" in the nation's power grid, "so the Federal Energy Regulatory Commission is considering allowing the change." The article notes that variation would throw off the clocks on many appliances, which use the constant rate to keep time. "Renewable energy is one primary reason FERC cares about frequency variation," Popular Science notes, since renewable sources usually fluctuate in terms of the amount of energy they produce. "One trade group that has studied the potential effects says East Coast clocks could run 20 minutes fast over a year, and timepieces on the West Coast clocks would be off by about 8 minutes."

The AP (6/28) notes that the FERC is proposing to let the rate vary as an experiment, which "is tentatively set to start in mid-July, but that could change." Demetrios Matsakis, head of the time service department at the US Naval Observatory, said "this will be an interesting experiment to see how dependent our timekeeping is on the power grid."

I have some comments, but I am going to loose power shortly. The comments will be later.

.

Well I know allot of T-101-104 time switch's that might be affected, the only clock in my home I'm not sure of (and I not taking it apart) is the one on my stove, the microwave has its own oscillator the one here in my computer room is atomic, the rest of the house are battery wall clocks, and the alarm clocks are battery back up, so none of them use the power line for reference.

Oh I almost forgot my sprinkler system timer that is old school with a synchrotron clock motor, but I don't use it as the water bill hit $270.00 for just using it one month, the grass can get brown for that.

 

[jim dungar]

With manual 'spring forward' and 'fall back' based on DST, the accuracy with how I set my clocks twice a year, causes them to never show the same time anyway.:ashamed1:

 

[don_resqcapt19]

110628-0842 EDT

From today's SME daily briefing:

Greater Grid Frequency Variation Could Save Utilities Money, Aid Renewable Usage.
Popular Science (6/28, Boyle) reports "utilities could save energy and money by allowing for greater frequency variation" in the nation's power grid, "so the Federal Energy Regulatory Commission is considering allowing the change." The article notes that variation would throw off the clocks on many appliances, which use the constant rate to keep time. "Renewable energy is one primary reason FERC cares about frequency variation," Popular Science notes, since renewable sources usually fluctuate in terms of the amount of energy they produce. "One trade group that has studied the potential effects says East Coast clocks could run 20 minutes fast over a year, and timepieces on the West Coast clocks would be off by about 8 minutes."

The AP (6/28) notes that the FERC is proposing to let the rate vary as an experiment, which "is tentatively set to start in mid-July, but that could change." Demetrios Matsakis, head of the time service department at the US Naval Observatory, said "this will be an interesting experiment to see how dependent our timekeeping is on the power grid."

I have some comments, but I am going to loose power shortly. The comments will be later.

.

How can the utilities save money by running "fast"???

 

[hurk27]

How can the utilities save money by running "fast"???

maybe because mechanical meters will run faster then the actual load allowing them to make more off a customer?:blink:
I know pumps and blowers and fans will pull more energy if they run faster then design, but I don't know how much other types of motors will pull if over sped a little, if any:?

The other problem is going to be machinery system timing, machines that use the motor to time a production line can be affected if motors speed up or slow down, a 4 pole motor will not track the same speed change as a 2 pole motor when changing the frequency as a source of speed control unless some kind of servo or feed back loops are in place, I worked a a few plants that used manual operator control to sync the conveyor belts by hand, and this is where it will be a problem.

 

[Besoeker]

110628-0842 EDT

From today's SME daily briefing:


I have some comments, but I am going to loose power shortly. The comments will be later.

After you get tight power back?

 

[rcwilson]

Frequency was not always controlled, becasue the utilites saw no need. In the early 1900's, textile plants in New England had trouble with varying speeds on their looms causing variations in the fabric or machine jamming as the power system frequency wandered a few hertz. Other industries also had issues, but the utilities had no motivation to change.

A GE engineer developed a turbine governor that maintained generator speed much better than the existing systems, many of which were manual. But he couldn't sell any. There was no perceived need. At Christmas, he sent the wives of all the utilitys' executives a beautiful mantle clock with an electric motor drive (Synchrotron). The wives complained that the pretty clock did not keep time accurately. He then sold a lot of turbine governor upgrades.

Today, there are few clocks that keep time with a motor. With the suggested change, industries will actually have better frequency because the time correction would be removed and the system could stay closer to 60 Hz more of the time. NERC is not advocating removing frequency controls, just removing the artifical adjustement of system frequency.

 

[Besoeker]

maybe because mechanical meters will run faster then the actual load allowing them to make more off a customer?:blink:

I made a similar, equally serious point, in post #13.

I know pumps and blowers and fans will pull more energy if they run faster then design, but I don't know how much other types of motors will pull if over sped a little, if any:?

I can't think of any motor driven application where a speed increase would reduce the power required.

The other problem is going to be machinery system timing, machines that use the motor to time a production line can be affected if motors speed up or slow down, a 4 pole motor will not track the same speed change as a 2 pole motor when changing the frequency as a source of speed control unless some kind of servo or feed back loops are in place, I worked a a few plants that used manual operator control to sync the conveyor belts by hand, and this is where it will be a problem.

The absolute speed increase would be different but the ratio of the speeds would remain the same all other things being equal.
But you probably wouldn't want to use standard mains driven cage induction motors anyway for an application where timing is crucial. Their speed varies somewhat with loading.

 

[wirenut1980]

How can the utilities save money by running "fast"???

I think that quote was saying that the frequency is very tightly regulated by generating plants. With large scale solar and wind connecting to the bulk transmission grid, the fear is that having those power outputs varying all the time, it might be tougher to keep that frequency nailed down to 60 Hz +/-.03 Hz or so. It sounds like this is a test to see how much the frequency can vary before electrical loads take notice. Just my take on the article. By the way, I work at a utility and this is the first I am hearing of this test (although I do not work in the transmission planning group or anything).

 

[Jraef]

Doesn't mechanical mean mechanical in the sense that they are clockwork with a spring and an escapement mechanism?
i.e. mechanical as opposed to electrical....

I would say so, but I think he may have meant synchronous motor based timers and clocks, as opposed to electronic.

 

[Besoeker]

I would say so, but I think he may have meant synchronous motor based timers and clocks, as opposed to electronic.

Possibly so. Not so many of those around now, though.