Power Grid Freq Variations To Be Allowed

[Erik]

I smell issues arising with this...

Erik

[trader4]

I have one issue already. The linked article comes up as unavailable.

[Dean Hoffman]

A short article here: >

Does it really take that much effort to synchronize the grid's frequency?

[Rebel1]

Try here:

[Ed Pawlowski]

I have no idea, but according to the articles, yes.

I know that a clock motor will be affected as you change from 60 cycles, but digital? I thought they had something to do with a crystal frequency oscillation. Or is that just watches?

"But wall clocks and those on ovens and coffeemakers - anything that flashes "12:00" when it loses power - may be just a bit off every second, and that error can grow with time."

[The Daring Dufas]

You have to copy and paste the whole link to your web browser because the bottom line wasn't automatically highlighted as a link. It happens all the time with some news readers. That's why I use the address shortening site "

" whenever I want to post a very long address. :-)

TDD

[George]

Consider the government dufas who is in charge:

"Tweaking the power grid?s frequency is expensive and takes a lot of effort, said Joe McClelland, head of electric reliability for the Federal Energy Regulatory Commission.

"Is anyone using the grid to keep track of time?" McClelland asked. "Let?s see if anyone complains if we eliminate it." "

I guess he doesn't know about how clocks with synchronous motors operate.

I guess he is trying to top Obamas technically incompetent FCC chairman who gave permission (after his boss got a big donation) to proceed with a system that interferes with GPS?

[Smarty]

Apparently Joe Mc Clelland is an electrical engineer. Thankfully not another lawyer who is clueless about technology:

[The Daring Dufas]

Uhem! "Dufas" is a proper family name, I hope you mean "doofus" which describes a complete dolt. As far as I know none of the Dufas family is in charge of the national power grid. ^_^

TDD

[HeyBub]

It won't happen if you surround the link with angle brackets ().

[Salmon Egg]

So what. Cumulative phase error on rhe grid was allowed to grow pretty large. I think I remember a minute error or more. The total cycle count, however was always corrected, often late at night.

Applications that required accurate frequency provided their own standards. It was a big business for HP and others. Television used a field rate of 60/sex. My entire remembrance of commercial TV has been standards that provided their own synchroinzation that did not require accurate timing from the grid.

[Pete C.]

Most anything that "flashes 12:00" is going to be using a crystal timebase and not care about power line frequency. They flash 12:00 since when they loose power they need to have the time set again, not anything to do with line frequency.

There are still a great many timing devices that rely on synchronus motors and thus line frequency, and these mostly have just dials, such as timers for sign and landscape lighting, water softener regeneration, water heater timers and the like.

[Charlie]

A long time ago I was working at company that was running a lot of equipment that was using the frequency of 60 Hz power line to control some critical processes.

I got the task of getting the specs of the frequency tolerance. It took a few phone calls to get to the engineering offices of Boston Edison. The engineer I reached told me the allowable frequency deviation and reminded me of something I had learned years before. If alternators running in parallel are not in phase,one tries to act as if it were a motor and the system could lock up, We had done this experiment in an AC power lab coupling a pair of alternators that were being driven by DC motors so that their speeds could be adjusted and they could be brought into phase with each other. Students who tried to put them in parallel when they were not close enough got to produce a pretty loud squeal from the complaining equipment.

As the electric company engineer and I talked he pointed out that the Great Northeast Blackout in 1964 was not simply that some parts of the grid had been overloaded but that a surge/spike/anomaly had created a phase mismatch which snowballed along as some units fell out of the allowable frequency and knocked alternators of the grid. The short term fix was to get off the grid and come back on when the frequency mismatches had been resolved.

At any rate, I can hardly wait to see what happens,

Charlie BSEE 1956

[HeyBub]

There are a LOT of things that depend on 60Hz. Since forever 60Hz has been a standard piped into every establishment in the country. The article mentioned traffic lights, security systems, and computers, but thousands of other devices depend on a stable line frequency.

To let the frequency meander all over the place would be similar to letting the National Bureau of Standards allowing the official meter to vary by one or two millimeters per day.

On the other hand, this change will open a new business opportunity to provide standard frequency power.

[jhardis]

Ah, no...

Anyone who has a device with a crystal oscillator timebase knows that the device has to be reset to the correct time occasionally. On the other hand, plug-in devices that use the 60 Hz signal for the timebase have been (up until now) essentially perfect since the signal has been manually twiddled to make it so. (There is actually a 10 second tolerance in the East, less in the West.) And implementation is dirt cheap: you capacitively couple to the power line, use a Schmitt trigger, and some divide-by-60 counters. With better performance at less cost, using the power-line frequency as a reference is the preferred method.

Thing become ambiguous in plug-in devices with "battery backup." These devices do have crystal oscillators to ride out the power outage. When the power is on they can either use the crystal oscillator as reference, or the power line as reference, however the device was designed.

- Jonathan

[hrhofmann]

You are the first poster to actually get it correct. Thanks!!!

[aemeijers]

On any long-haul telecom circuit, like the ones the Internet runs on, somewhere in the path for that circuit, is a rack in a basement somewhere with a cesium clock. All the other racks that particular circuit runs through, from point A to point Z, anywhere in the world, have to be told to take that clock's word as gospel. When they screw up, and have 2 different clocks in the path, sometimes it can get amusing if they get out of synch.

[bob]

To change the frequency they have to brake or accelerate the generator. What I can't understand is which station is in charge of monitoring the frequency and issuing commands to other power stations to speed up or slow down?

Frequency variation is not a big deal. When you have a power outage, the voltage and hence frequency go to zero in a haphazard way. So if line frequency variation would cause chaos, power outage should cause many times the chaos.

But we have been living with the ocassional power outage, I think the minute line frequency variation is not going to do any worse than power outage. In fact it probably won't affect anyone at all.

[The Daring Dufas]

Your link came out fine but I think I've seen that fail too depending on the software being used or the number of copies of the original message breaking the link. That's why I always choose to shorten the URL so it doesn't break after it's forwarded several times. Perhaps I'm too neurotic about it.

TDD

[Gz]

Seems like the variation allowed, the more variation syncing is problematic. The whole grid is always loosing power to all the stations producing slight variation pulling on each other.

Crystals tend to be stable, but there are times when the crystal makes a steep, then needs to be calibrated. A primary frequency standard uses a quartz oscillator with another correction loop like from cesium standard.

Greg