“Experiment” on the US power grid will change the way some clocks and other equipment function.
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.
Calm Down Everybody!
Large utility turbines are “tuned” for a specific speed/frequency and any significant deviation will cause them to be damaged; you can bet that utilities will keep the frequency pretty darn close to the design speed, if for no other reason than to avoid voiding warranties.
Load shedding schemes, which utilize relays which measure frequency and are programmed to shed load when the frequency drops below certain thresholds, this will also limit the range of excursion on frequency.
Currently utilities match load vs. generation by making certain their load/generation balance tracks above and below the balance point several times an hour. On hot summer days, generation tends to “sag”, and frequency slips in the entire grid (the largest grid includes all of the states and provinces east of the Rockies, except Texas, which is independent.) Utilities would agree to overspeed slightly at prearranged times to re-synchronize the grid versus a virtual synchronous clock. Anytime major generation is suddenly lost, say a 500 MW unit in Florida trips off because someone bumped a trip unit, there is no way the grid can instantly make up for the lost generation; the entire grid East of the Rockies, all the way to Northwest Canada, slows slightly as the inertia of every spinning generator on the grid (and to a certain extent motors) is converted into energy to make up for the lost generation.
The routine excursions in frequency will not affect 99.999 percent of equipment, in fact, a lot of equipment, like motors can be used at 50 or 60 HZ, as long as you take into account changes in heating/cooling effects, and there is no effect at all on incandescent lights and toasters and such.
So now we know what Steven Chu was calling the low-hanging fruit of efficiency.
This is a step towards the smart grid – they’re going to use tiny variations in frequency to indicate load so they can institute variable pricing and charge us a lot more for electricity in the late afternoon and evening when we really need it.
@ur momisugly temp says: June 25, 2011 at 3:37 pm
I fear that you are spot on. This sort of thing is nothing new, and is precisely how we get an average of 86,000 pages of new regulations EVERY YEAR!
Anything that runs on a household/small office UPS system when the power goes off will survive – those produce non-sine wave, non-60Hz power, and the bigger problem is the non-sine wave power, that’s what makes transformers sound funny on a UPS.
Not a real big deal, I expect, except for clocks, and there are millions of people who rely on cycle counting clocks still.
Stop being such a bunch of babies, RESISTANCE IS FUTILE, YOU WILL BE ASSIMILATED.
/JK
According to the IEEE discussion forums, a variation of 0.5Hz will trip some of the inter-tie safety trip devices so we can’t be talking about large frequency variations across the grid or it would shut down. It may be that the US government is allowing some small power suppliers (solar/wind) to supply off frequency. Other “big” suppliers can regulate the grid frequency by adjusting their output. But this sounds like indirect taxation – making the big power suppliers manage the system while allowing wind and solar to input with out appropriate frequency matching regulation. Just a guess, but it makes sense from what I have read.
I think Claude Harvey at June 25, 2011 at 3:27 pm had it right.
There was an episode of the old Superman TV series where they did this to speed up the clocks in this guy’s impenetrable chamber. His plan was to stay in the chamber until the statute of limitations ran out on his crime. The fast clocks tricked him into emerging early and he was busted.
Classic TV!
My Mr Coffee machine must have gotten the word early, since it’s been gaining a few minutes a day for some time, and is now about twelve hours ahead. I’m retired and don’t use the timer to start brewing, so I just find it interesting that its supposedly synchronous motor could be so far out of sync. Come to think of it, it probably doesn’t have a synchronous motor, but an electronic counter of some sort.
Well, that was illuminating. So to speak.
It would appear that very few people on this board have more than a smattering of understanding about electricity.
Look at it this way. If the generators can’t keep the dynamos synched with the grid then welcome to Puerto Rico occasional power.
Who thinks of these STUPID ideas?
The mechanical clocks use the 60 Hz to keep track of time, yes it can vary some, but in a day, it must be 24 hours x 60 minutes x 60 seconds x 60 Hz. Otherwise, the time is off. LED Clocks and your VCR keep track counting the 60 Hz too.
IF they decide to go with this stupid idea, who is going to pay for the replacements of all the clocks?
I suspect that this is something to do with the intermitency and variability of green energy being accomodated by the grid. That said, I am unsure that this will have a significant effect on consumer electronics since the mains AC power in to these units is adated by a power supply unit (PSU) down to between 1.5 to 12 volts DC depending upon application. Highly sensitive equipment has a sophisticated PSU specifically designed to filter out ‘noise’ and maintain a constant DC supply voltage. For HiFi units you can buy equipment that will further filter the mains to provide an even steadier input supply.
This will also present a problem for those with home solar panels, and sell their excess power to the power company.
They must use an inverter, and connect through a GTI (grid-tie-in) circuit. If they don’t get the frequency right, then feedback in BOTH directions will be present.
Spinning reserve costs money, the generators have to be coupled to the system but not be actively producing power. When wind power fluctuates the power on the grid this reserve is there to accommodate the change, maintaining 60 Hz. I suspect that the object of the exercise is to reduce the spinning reserve requirements so that this lost generation can be put to use providing real power to the system. Which will effectively increase the installed capacity of the system.
3 phase system voltages rise and fall at different times, each phase is displaced by 120 electrical degrees so that the voltage peaks 3 times each cycle. If you reverse connect any two phases in a three phase system the phase rotation will reverse, causing motors to run in the reverse direction.
Before connecting any 3 phase equipment a check is made to ensure that the phase rotation is correct.
Another thing to keep in mind is that frequency control units, that is the generating units that can change throttle fast enough to maintain frequency, are high temperature steam plants. They are usually coal or gas powered.
Hydro and Nuclear plants are normally run ‘block loaded’, that is with their governors set fairly insensitive to frequency changes. 5% ‘droop’ is what block loaded generators are set to. That is, they would require a 5% change in line frequency to change their throttle power level by a factor of 100%. As you might imagine, normal power line frequency excursions are much smaller than 5% so their power output remains relatively constant.
Governors in frequency control units are set to lower ‘droop’ values, but still high enough to maintain system stability. Frequency control, in the form of maintaining cycle count over time is done electronically now. The frequency control unit governor set point is adjusted up and down to maintain long term cycle count.
Right off the top of my head I cannot see any reason to eliminate this function to match up with wind and solar generators. Most of those units use electronic inverters to connect to grid so frequency does not matter to the mechanics of the equipment. I suppose it is possible that there are some synchronous wind generators (generating 60 Hertz directly from the generator windings) but this seems more expensive a design than simply rectifying a wind generator alternator output and applying that to an inverter to match with the line frequency.
There might be some advantage in allowing the frequency to ‘droop’ intentionally over some narrow predictable range. Line frequency could then provide a signal to customers when generation capacity is low or high to allow them to adjust their loads appropriately. Unfortunately, I don’t think this is part of the picture. If it was, I’d expect it to be described in detail to justify the change.
So what might the reason be? A tiny increment less coal or gas burned at night to make up cycles? Seems like a dumb idea to me.
So, how much are the utilities saving by not re-synching each night?
Will this make the annoying flickering of fluorescent bulbs even worse? This may be Edison’s final slap at Tesla.
GaryW,
It could be interesting. What if with today’s technology we could build into our appliances a demand side droop of say 2%, regulated by the manufacturers. So if during a low frequency excursion the collective load were to respond before the generators did the heavy lifting, there would be fewer brown outs or under-frequency load shedding events where the customers are disconnected from the system to preserve frequency. I was thinking about zero droop for demand side but that probably would cause instability because there would be no inertia in the system.
Modern elecronic appliances with switch mode power supplies will not be ‘phased’ by the reduced frequency stability but some older stuff with linear power supplies and 60Hz optimised transformers may operate at reduced efficiency and the variable frequency could modulate the secondary voltage enough to cause problems ranging from faulty operaton to reduced life or even rapid failure if the instability is severe enough. The problems could be far more reaching for industry though. Any motor driven equipment that employs power factor corrections is vulnerable. Change the frequency and you automatically modulate PF correction with potentially catastrophic results if resonance is achieved between the load inductance and XC correction.
The odd part about this is that there’s absolutely no need to reduce frequency regulation of the grid. The notion that 1% accuracy is costly is really absurd. With the low cost of GPS receivers today it’s now cheaper than ever to synchronise all parts of the grid incuding greem sources such as wind and solar. If anything there should be new regulations applying to green energy sources to ensure that stability is not compromised.
As we move into the new green future the problems with frequency stability and and harmonic distortion are only going to get much greater.
This announcent is completely out of phase with common sense.
Nobody remember power line surges and the blackout in New York way back when?
Thanks for the information – worthwhile comparing notes!!
Here in Australia, we are in the process of a compulsory changeover to smart meters with the cost of the meter charged to your power bill, but you never own the meter. There are concerns over the way power is charged for and third party electrical engineers are selling after market installations that are claimed to reduce bills while maintaining a more constant power load to your home appliances.
All I know is that since installation, bar heaters don’t work that well and turning lights on and off cause the other lights to flicker, and the new energy saving globes burn out very quickly, (3 months ?) and while I have not had motor burnouts, many people are also reporting that shortly after installation of the meters they have had appliance motors burn out in washing machines and refrigerators -perhaps coincidence – I hope so. The smart meter is 1 phase 2 wire 240 volt 15 – 100 Amp, CI 1.0, 50 hertz it says.
Many people may not realize this. Power companies buy and sell power, based on supply and demand. This leads to very interesting situations. When a power company is generating too much power, it is often cheaper to sell the power than to power down the generators. However, as often happens, all the power plants sometimes have too much power at the same time. What happens next is a hoot!
The price of power then goes negative. Yes negative. Power companies acutally pay other power companies to take their excess power! Especially places like California where they have lots of “green” power. They can’t just turn the power on and off, so when they have too much, and there is no one who needs power, they actually pay people to take power off their hands. As much as $.17 KWh.
To bad you and I the lowly consumer aren’t in on this deal. I’d be more than happy to turn on my electric heaters if someone was paying me. Instead you and I end up paying the retail price, at the same time the power company is paying someone else to take the power! So much for smart meters.
It’s not just a few people with old style clocks. Many older PLCs use the 60Hz as a time reference to control industrial processes. A lot of European equipment designed to run on 50Hz won’t run here without a buck-and-boost. There may be a few factories put out of commission by this change.
Fundamental Transformation.
You guys that are telling us to calm down, I sure hope you are right. Because if this screws up my computer, I’m going to be p.o.ed!
The government is somehow going to find a way to screw up our power grid and turn us into a third world country by these so-called “experiments.”
Solar inverters are required to disconnect from the grid when the frequency goes out of spec which for 60 Hz is 59.3 – 60.5 Hz. They must also respond to this change within 10 cycles. The inverter will reconnect once the power is in spec for 5 minutes (UL1741/IEEE1547), There are going to be a LOT of idle solar power systems if this is allowed to go too far. There is a call to make changes to the standards so that solar can actually help stabilize the grid during sags and short events.