It hertz when you do that – power grid to stop regulating 60 Hz frequency

Watts Up With That? ^ | June 25,2011 | Anthony Watts

[brityank]

It hertz when you do that – power grid to stop regulating 60 Hz frequency

Posted on June 25, 2011 by Anthony Watts

“Experiment” on the US power grid will change the way some clocks and other equipment function.

A 60 hertz sine wave, over one cycle (360°). The dashed line represents the root mean square (RMS) value at about 0.707 Image: Wikipedia)

Story submitted by Joe Ryan

The AP has released an “exclusive” story concerning the nationwide “experiment” that will be conducted on the US power grid. The experiment will relieve the power providers from the duty of regulating the frequency of power on the line.

Normally the power stations condition their power to a frequency of 60 cycles a second, a frequency that many old clocks use to maintain their time. With the new standard, or lack of standard, these clocks will stop keeping time properly.

But the problem is more than that.

First, we have this gem from Joe McLelland who heads the Federal Energy Regulatory Commission (from AP article):

“Is anyone using the grid to keep track of time?” McClelland said. “Let’s see if anyone complains if we eliminate it.”

… forgive me for not getting warm fuzzies from this. Likewise, Demetrios Matsakis, head of the time service department at the U.S. Naval Observatory, had this to say (AP Article again):

“A lot of people are going to have things break and they’re not going to know why,”

So, we have what appears to be an untested, for the hell of it, “experimental” major change to the US electrical grid coming in a few weeks and those in charge aren’t really sure how it will work or if it may break something?

Not only is this what a LAB is for, but it is also something that the Federal Government should be TELLING people about in advance, and not in an AP “exclusive” press release.

[reg45]

... and your music will play slower and at the wrong frequency.

[dila813]

This is being done to make it cheaper to hook windmills up to the grid.

They have to realize that if you introduce this noise to the electrical system that all kinds of electronic devices will be affected. Not only that, the chances for surges when two phases come in sync spiking voltage.

[HiTech RedNeck]

The stability of frequency (actually, cumulative cycle counts) across a grid was only a secondary effect of a grid in which breaches could be easily healed.

Tolerance experiments like this, even if well intended (such as heroic efforts to keep power going in a heavily sabotaged grid, even if the frequency walks up to 61 Hz or down to 59 Hz) really need to start in the lab. This can’t be like trying to cut over to Y2K capability in 1990.

[CORedneck]

Bingo ! Attack on our comfortable way of life. These elitists feel that only they are anointed to enjoy the good life and everyone else who are not part of “their club” should be forced to suffer for the hell of it !

> These people must lay awake at night thinking up new ways to inconvenience people.

[dljordan]

“These people must lay awake at night thinking up new ways to inconvenience people.”

No, there’s something else involved, probably money.

[cc2k]

Melas wrote:

It’s not going to hurt your alarm clock. That’s the problem with a story like this: So few people are going to truly understand it when they read it. Unless you are using an ancient digital (looking) alarm clock that flips the numbers into place with a motor, you’re in good shape.

Well, there's a difference between "causing harm" and "causing inaccurate operation."

For clocks, I doubt there's any permanent harm. However, any "traditional dial" clock (with a big hand and a little hand, and maybe a second hand) which plugs in the wall is potentially affected. Most of those use a synchronous AC motor to drive the mechanism at a constant, known speed. They are accurate because over time, total cycles/total seconds always is very close to 60 cycles/second. There can be shorter periods when the frequency is off in one direction or another, but up until now, the totals were tightly regulated.

For digital (LED or LCD) clocks, the situation is more difficult to estimate. Any clock with a "battery backup" should be unaffected. Most of those have a quartz crystal timebase, so that they can continue to keep time when on the backup battery (a DC source). However, digital clocks without a battery backup feature are far more likely to use the line frequency as the timebase. Why add the expense of a quartz crystal and the associated circuitry when you have a (up until now) reliable 60Hz signal coming in on the power line.

Bockscar wrote:

Something tells me it will ‘disrupt’ more than clocks.

You are probably correct. Anything with a synchronous AC motor will run at a speed determined by the line frequency. This could affect any device with a synchronous motor.

For asynchronous motors, the affects will be more subtle and depend on the device. For example, for induction motors (brushless motors very commonly used where precise speed isn't needed), operating speeds are stable with load (IE, increased load will slow it down, decreased load will allow it to run faster) above the 'peak torque' speed. Above that speed, if you slow the shaft, the torque increases. This makes that type of motor largely self regulating for the load. Below 'peak torque' speed, operating speeds can be unstable with load. Motors operating in that range can stall out or the speed can oscilate, sometimes in unpredictable ways. The big issue is that 'peak torque' speed varies with power supply frequency.

This is not a change that should be implemented nationally on a "let's see what happens" test. There aren't a lot of positive outcomes, and there are a lot of risks of negative outcomes. This is a change that should be announced at least 10 years in advance, giving anyone who owns critical electrical equipment a chance to test the effects of supply frequency changes on their equipment. This also gives manufacturers lots of advance time to release new designs and document which of their devices need replacement for "variable supply frequencies" and which will continue to operate as designed in that environment.

[Crim]

They have been pushing for people to replace all their appliances....they just found a way to force it...

Nudge turns to shove...

[Ed Condon]

Let’s go back to “local time”, when the sun is at its highest, it’s noon.
That system worked in this country for about a hundred years, until the railroads needed something better.

Since only railroad nuts ride the trains, and most do it for the nostalgia, it won’t matter what time it is.

[dynoman]

Nothing is going to change. The frequency is controlled at the power plants themselves. I work at a power plant, our frequency correction built in to our local control logic operates whenever the generator rpm moves a few RPM from 3600. I see it operate at 3601 on the high side and 3597 on the low.

[Bockscar]

I think you have nailed it.

[gitmo]

This is HUGH!

Or not.

I don’t know which.

[cc2k]

Doe Eyes wrote:

From what I can tell, the worst case variance for 60 Hz power would be about .01 Hz. So the frequency could vary from 60.01 to 59.99 Hz. I cannot imagine that the medical industry designs equipment that cannot deal with this level of frequency variance. I also cannot see how this would adversely affect home appliances.

OK, I clicked through twice to get to the "AP Exclusive" story. It appears you are correct. That story mentions an error of 14 seconds in one day (14 seconds in 86,400 seconds). That works out to about 0.01Hz for a 60Hz base signal. That should not be a significant deviation in terms of motor reliability. But 14 seconds/day error for clocks is significant.

[Melas]

How does the hospital equipment double check that an individual internal crystal timebase has not “gone rogue”?

It's not really an issue. The service life of say a morphine pump is determined by life of the parts that last only a tiny fraction as long as the quartz (typically)crystal. Piezoelectric materials like quartz are used for their accuracy. When you apply current to the crystal, it's bound by the laws of physics. It will oscilate at X frequency as per it's size and cut, and unless an outside force acts upon it, or the steady decay of the crystal (measured in lifetimes) alters it physically, it cannot oscillate at a different frequency.

Another thing not mentioned here is that relying on the hertz from the socket isn't a very accurate measure of time. One of the great boons of the digital advances in the 70's was that quartz time keeping was much more accurate.

Also, note that the quality of materials used for time keeping varies. The ones say in cheap consumer clocks and watches are manufactured by the billions every year, and go for pennies. On the other end of the spectrum some are made to extremely precise specifications, and can be rather expensive. You can bet that the X-ray machine which also uses piezoelectric oscillation to control the length of the burst, isn't using a cheap one. Btw, your nurse is your primary defense against any malfunctioning equipment in the hospital.

[brityank]

This is not a change that should be implemented nationally on a "let's see what happens" test.

Thank you both - glad to see some knowledgeable FReeper input.

As others have said, this is just a way to let the variable inputs of solar and wind derived energy have access to the grid with minimal compliance on their part to match what already is the standard.

[mouser]

The power grid is made up of many chunks and hundreds of generating places

to tie two generators together and make it work or two segments of the power grid the sine wave of both have to be the same if not one is + while the other is - and they cancel out each other or fight if you will

even if the frequency's are off just a bit and they start at the same at some time one will pass the other and they will be out of phase and something will have to give

[dynoman]

I actually know something about this. Ping to post 49...

[dynoman]

“Wheres the BS meter?”

No kidding, check out post 49...

[VeniVidiVici]

bump

[Melas]

For clocks, I doubt there's any permanent harm. However, any "traditional dial" clock (with a big hand and a little hand, and maybe a second hand) which plugs in the wall is potentially affected. Most of those use a synchronous AC motor to drive the mechanism at a constant, known speed.

No. Although they physically resemble the old clocks that used synchronous motors, almost any clock sold in the last 30 years uses quartz, analog or not. For giggles I just tried to shop for a synchronous motor driven clock, and outside of couple punch-clocks for employees, I couldn't find a single one outside of older clocks being sold to collectors. I did however come upon a couple of resources on how to build your own as a fun retro-project.

[dynoman]

Not.

Check post 49. If this is true we will be turning off frequency correction where I work so will every other power plant - ain’t gonna happen.