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Home > Archive > Alternative Power sources > February 2006 > Energy Worries In Ontario Canada?
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Energy Worries In Ontario Canada?
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| Came across this announcement today, about today. Don't know about you,
but *I* am awfully glad I'm not living on the Ontario grid. This does
not bode well...
Quote:
The Ontario Independent Electricity System Operator (IESO) is planning
a voltage
reduction test for Thursday, January 19, 2006. The test will consist of
two
province-wide voltage reductions:
1. A reduction of 3%, from 9:30 EST to 11:00 EST, and
2. A reduction of 5%, from 17:30 EST to 19:30 EST.
The purpose of the test is to establish and record the load reduction
resulting from
a system wide voltage reduction and to locate potential operational and
customer
problems that may occur. It is an important part of training for
emergencies for
the IESO and market participants.
This test is within the acceptable tolerance of most electrical
equipment and
systems and will probably not be noticeable. However, a slight
decrease in
equipment / system performance may occur. It is recommended that
sensitive
electronic equipment be monitored and that any disturbance be reported
to Utilities
Management Services to the attention of Al Miner at (613)775-4142 for
the National
Capital Region and to Darrell Dirks at (416) 512-5693 for the Ontario
Region.
The IESO reserves the right to reduce voltage by up to 5% during
emergencies that
may result in a Public Appeal. This level of voltage reduction is
considered
reasonable and may occur at anytime without notice. Therefore, as we
know when the
voltage reduction will occur, we have an opportunity to identify any
problems that
may occur strictly due to a voltage reduction.
| |
|
| You don't believe in preventive maintenance for any or your
equipment, and you look fo reasons to complain, don't you?
"DJ" <dj_macintyre@hotmail.com> wrote in message
news:1137678461.151215.12680@o13g2000cwo.googlegroups.com...
: Came across this announcement today, about today. Don't know
about you,
: but *I* am awfully glad I'm not living on the Ontario grid.
This does
: not bode well...
:
: Quote:
:
: The Ontario Independent Electricity System Operator (IESO) is
planning
: a voltage
: reduction test for Thursday, January 19, 2006. The test will
consist of
: two
: province-wide voltage reductions:
:
: 1. A reduction of 3%, from 9:30 EST to 11:00 EST, and
: 2. A reduction of 5%, from 17:30 EST to 19:30 EST.
:
: The purpose of the test is to establish and record the load
reduction
: resulting from
: a system wide voltage reduction and to locate potential
operational and
: customer
: problems that may occur. It is an important part of training
for
: emergencies for
: the IESO and market participants.
:
: This test is within the acceptable tolerance of most electrical
: equipment and
: systems and will probably not be noticeable. However, a slight
: decrease in
: equipment / system performance may occur. It is recommended
that
: sensitive
: electronic equipment be monitored and that any disturbance be
reported
: to Utilities
: Management Services to the attention of Al Miner at
(613)775-4142 for
: the National
: Capital Region and to Darrell Dirks at (416) 512-5693 for the
Ontario
: Region.
:
: The IESO reserves the right to reduce voltage by up to 5%
during
: emergencies that
: may result in a Public Appeal. This level of voltage reduction
is
: considered
: reasonable and may occur at anytime without notice. Therefore,
as we
: know when the
: voltage reduction will occur, we have an opportunity to
identify any
: problems that
: may occur strictly due to a voltage reduction.
:
| |
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"Pop" <nobody@devnull.spamcop.net> wrote in message
news:9SNzf.9468$8r1.7773@trndny01...
> You don't believe in preventive maintenance for any or your
> equipment, and you look fo reasons to complain, don't you?
>
Right on Pop
I used to work around a server farm. The electrical system was double
redundant. A mistake was make the system worked perfectly, not one load had
a problem. The manager had us escorted to the property line by the police.
He called every person he could think of. They all asked the same question,
"Was anything hurt?"
Not doing testing is irresponsible. Having employees that do not know what
to do is just stupid.
We have a nuecular reactor near by for power. The operators must have 40
hours of training in the simulator every month or they loose their license.
> "DJ" <dj_macintyre@hotmail.com> wrote in message
> news:1137678461.151215.12680@o13g2000cwo.googlegroups.com...
> : Came across this announcement today, about today. Don't know
> about you,
> : but *I* am awfully glad I'm not living on the Ontario grid.
> This does
> : not bode well...
| |
|
|
Pop wrote:
> You don't believe in preventive maintenance for any or your
> equipment, and you look fo reasons to complain, don't you?
Well, wrong on both counts, actually. I'm a Journeyman Millwright by
trade, aka Industrial Maintenance Mechanic. I also hold an Electrical
Contractor's licence, certified to install and maintain electricity
generation equipment, from nuke plants to wind farms.
If you wanted to do maintenance to an electrical system, there's not a
reason in the world you would "brown" the entire province. I'm thinking
that this test is to see that on days where consumption comes close to
exceeding production, as it did several times last summer, if they can
ever-so-slightly brown the grid to try to boost their supply. So,
basically, watering down the soup to try to feed the family. This would
probably be the best time of the year to do it, as the load is
managable right now.
Like I said, my decades of maintenance experience are saying that this
isn't for routine maintenance. Brown Ottawa, sure. Brown Toronto, sure.
Brown the entire province at once? They're seeing if they can thin the
soup, because i think they forsee the day they're out of stock and
they'll need to.
Again, glad I'm not in Ontario...
DJ
| |
|
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SQLit wrote:
> Not doing testing is irresponsible.
Absolutely. But have you ever heard of intentionally browning the
entire province for a test?
The only reason you would run that test is if you wanted it to be an
option later.
DJ
| |
| Derek Broughton 2006-01-19, 2:21 pm |
| SQLit wrote:
> Not doing testing is irresponsible. Having employees that do not know what
> to do is just stupid.
> We have a nuecular reactor near by for power. The operators must have 40
> hours of training in the simulator every month or they loose their
> license.
>
40 hours A MONTH? Seems slightly excessive. That's one week in four.
--
derek
| |
| Derek Broughton 2006-01-19, 2:21 pm |
| DJ wrote:
>
> SQLit wrote:
>
>
> Absolutely. But have you ever heard of intentionally browning the
> entire province for a test?
> The only reason you would run that test is if you wanted it to be an
> option later.
Precisely - didn't you read that in the announcement? The last paragraph
states: "The IESO reserves the right to reduce voltage by up to 5% during
emergencies that may result in a Public Appeal. [that's part of Ontario's
Emergency Measures legislation] This level of voltage reduction is
considered reasonable and may occur at anytime without notice. [which any
utility in North America would tell you is within their operating norms]
Therefore, as we know when the voltage reduction will occur, we have an
opportunity to identify any problems that may occur strictly due to a
voltage reduction." - ie, since we have to be able to do this in an
emergency, we'd darn well better know that it can be done safely.
--
derek
| |
|
|
"DJ" <dj_macintyre@hotmail.com> wrote in message
news:1137690274.775458.301060@g44g2000cwa.googlegroups.com...
>
> SQLit wrote:
>
>
> Absolutely. But have you ever heard of intentionally browning the
> entire province for a test?
> The only reason you would run that test is if you wanted it to be an
> option later.
>
> DJ
5% is not a brown out. Options are good. Which would you prefer a brown out
or dark?
Get to 10-15%, now your in brown down conditions. I will bet unless you
have an RMS recording meter connected you will never see the test.
Your in Canada, so IEEE 519 may not be the standard there. It says that the
utility must hold plus 7% to minus 5%. Next paragraph says except for
short periods of time.
Our utility does not tell us when they do their testing. The fact yours is
announcing it would make me feel a lot better.
| |
|
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"Derek Broughton" <news@pointerstop.ca> wrote in message
news:1lv4a3-6tt.ln1@news.pointerstop.ca...
> SQLit wrote:
>
what[color=darkred]
> 40 hours A MONTH? Seems slightly excessive. That's one week in four.
> --
> derek
Remember this is a nuke. The NRC has some stringent rules. Last time I
was on a tour out there the instructor threw them a curve while we were
there to show us how they handle it. I would have gone nuts with the horns
and lights. They calmly found and adjusted the situation in the simulator
and when on about their business. This happens to be the largest nuke in
the country, west of Phoenix about 55 miles, Palo Verde.
| |
| William P.N. Smith 2006-01-19, 3:21 pm |
| "DJ" <dj_macintyre@hotmail.com> wrote:
>Brown the entire province at once? They're seeing if they can thin the
>soup, because i think they forsee the day they're out of stock and
>they'll need to.
And are also interested in knowing if (or how much) it'll help. The
days of linear loads are over, many loads will respond to a drop in
voltage by increasing current to keep power continuous, and while they
certainly realize that a 5% voltage reduction won't cut power
consumption by 5%, they are probably interested in knowing by how much
it will decrease, and if they'll run into other problems.
It'll probably be painful for some small segment of the population,
but they are way better off knowing the characteristics of their grid
than just relying on engineering analyses.
| |
|
|
SQLit wrote:
> 5% is not a brown out.
True enough, by definition, it ain't.
> Options are good. Which would you prefer a brown out
> or dark?
Well, myself, being off-grid and in Quebec... probably the wrong person
to ask ;-).
> Get to 10-15%, now your in brown down conditions. I will bet unless you
> have an RMS recording meter connected you will never see the test.
Probably not, no.
> Your in Canada, so IEEE 519 may not be the standard there. It says that the
> utility must hold plus 7% to minus 5%. Next paragraph says except for
> short periods of time.
Last I heard, here, it's plus/minus 10%, but that's "heard", not seen.
Thing is, that's plus/minus ten to allow for normal fluctuation, but
when you intentionally go down five, that's not a whole lot of wiggle
room left for accidents.
> Our utility does not tell us when they do their testing. The fact yours is
> announcing it would make me feel a lot better.
It's not that they told us, it's that they felt it necessary to test
now. I called around to a few industrial friends, and yes, they were
also informed, because Hydro is expecting feedback, one way or the
other.
DJ
| |
|
|
William P.N. Smith wrote:
> And are also interested in knowing if (or how much) it'll help. The
> days of linear loads are over, many loads will respond to a drop in
> voltage by increasing current to keep power continuous, and while they
> certainly realize that a 5% voltage reduction won't cut power
> consumption by 5%, they are probably interested in knowing by how much
> it will decrease, and if they'll run into other problems.
That was my thought. How far can they go before commercial
refrigeration compressors and such start to overheat because the amps
went up because the volts went down...
> It'll probably be painful for some small segment of the population,
> but they are way better off knowing the characteristics of their grid
> than just relying on engineering analyses.
Oh yeah, I agree, better to test now than to just do it next August and
cross their fingers. Well, knowing what I've heard about Ontario Hydro
from some experts and consultants I know, well, you guys don't seem to
want to think about it anyway ;-).
DJ
| |
|
|
Derek Broughton wrote:
> Precisely - didn't you read that in the announcement? The last paragraph
> states: "The IESO reserves the right to reduce voltage by up to 5% during
> emergencies that may result in a Public Appeal. [that's part of Ontario's
> Emergency Measures legislation]
Yessum. In the business world, we call that foreshadowing ;-).
> This level of voltage reduction is
> considered reasonable and may occur at anytime without notice. [which any
> utility in North America would tell you is within their operating norms]
Very true. But that's "accidental" variation. Dropping it five points
off the start... what does that do to normal voltage flux?
> Therefore, as we know when the voltage reduction will occur, we have an
> opportunity to identify any problems that may occur strictly due to a
> voltage reduction." - ie, since we have to be able to do this in an
> emergency, we'd darn well better know that it can be done safely.
You read that, and I read " - ie, since we will probably be doing this
next summer, we'd darn well better know that it can be done safely."
DJ
> --
> derek
| |
| Derek Broughton 2006-01-19, 5:21 pm |
| SQLit wrote:
>
> "Derek Broughton" <news@pointerstop.ca> wrote in message
> news:1lv4a3-6tt.ln1@news.pointerstop.ca...
> what
>
> Remember this is a nuke. The NRC has some stringent rules.
I'm _very_ aware of that. There was a time when every single nuclear power
plant worker in Canada, and possibly South Korea, Iran & Pakistan, had been
trained by my father (not solely by him, just that amongst other things he
did the introductory course that everybody had to take). One week in four
for simulator training still sounds awfully high (and my father's no longer
around to ask what it's like up here, now).
--
derek
| |
| daestrom 2006-01-19, 7:21 pm |
|
"Derek Broughton" <news@pointerstop.ca> wrote in message
news:1lv4a3-6tt.ln1@news.pointerstop.ca...
> SQLit wrote:
>
> 40 hours A MONTH? Seems slightly excessive. That's one week in four.
I agree. Many plants have five 'crews' and a 'staff' crew. Training runs
in a six week cycle (along with all the shift-rotation). Some do it with
just a five week rotation, but never seen four.
So one out of every six weeks, a crew is in training for a week. But that
isn't full-time simulator. Lots of class room, quizzes, and periodic exams.
Not to mention 'required reading', 'operational-experience review', 'fitness
for duty testing' (pee in a bottle). So it works out to between 15 and 25
hours of actual simulator training every sixth week.
daestrom
| |
| daestrom 2006-01-19, 7:21 pm |
|
"DJ" <dj_macintyre@hotmail.com> wrote in message
news:1137690131.305220.246110@g43g2000cwa.googlegroups.com...
>
> Pop wrote:
>
> Well, wrong on both counts, actually. I'm a Journeyman Millwright by
> trade, aka Industrial Maintenance Mechanic. I also hold an Electrical
> Contractor's licence, certified to install and maintain electricity
> generation equipment, from nuke plants to wind farms.
>
> If you wanted to do maintenance to an electrical system, there's not a
> reason in the world you would "brown" the entire province. I'm thinking
> that this test is to see that on days where consumption comes close to
> exceeding production, as it did several times last summer, if they can
> ever-so-slightly brown the grid to try to boost their supply. So,
> basically, watering down the soup to try to feed the family. This would
> probably be the best time of the year to do it, as the load is
> managable right now.
>
That's exactly what it is. But don't be so alarmist about it. Just about
every ISO has done this sort of test (NY, PJM, NE... all of them).
Part of load management has always included several options. From starting
peakers, buying from neighboring ISO's, industrial customers that have
'voluntary reduction' contracts, utility controllable A/C and H/W units,
voltage reductions within 10%, brown-outs, to rotating black outs.
All reviewed by the FERC and state PSC's. These are 'graduated steps' to
avoid catastrophic blackouts. And they need to know how much load reduction
each step will provide so that various models ('state estimators') and
procedures can be put in place for them.
You're off-grid, so you shouldn't really care.
You seem to be just trying to make yourself 'feel good' by ranting how
unreliable Ontario power is going to be and that this somehow 'proves' they
are planning for brownouts and that you made the 'right' choice to be
off-grid. Are you that insecure in your decision?
Their preparations are probably going to make their grid *more* reliable.
daestrom
| |
|
|
These province-wide voltage reduction tests ( 3 % or 5 % )
have been a routine in Ontario for many many years.
Actual voltage reductions ( not tests ) occurred several times
during the summer of 2005 ( 3 or 4 times I think )
A 5 % voltage reduction will reduce demand by approx.
2 % ... which is about 500 MW during peak periods.
Nothing sinister in this.
The tests serve to iron-out customer problems ; train the staff; etc.
The actual voltage reduction - during times of grid/generation
difficulties - is just one step toward avoiding any blackouts.
If you wish to cry wolf, about the electricity supply in Ontario -
that's fine with me - but please don't use these routine voltage
reduction tests as an argument.
Regards.
>
>Pop wrote:
>
>Well, wrong on both counts, actually. I'm a Journeyman Millwright by
>trade, aka Industrial Maintenance Mechanic. I also hold an Electrical
>Contractor's licence, certified to install and maintain electricity
>generation equipment, from nuke plants to wind farms.
>
>If you wanted to do maintenance to an electrical system, there's not a
>reason in the world you would "brown" the entire province. I'm thinking
>that this test is to see that on days where consumption comes close to
>exceeding production, as it did several times last summer, if they can
>ever-so-slightly brown the grid to try to boost their supply. So,
>basically, watering down the soup to try to feed the family. This would
>probably be the best time of the year to do it, as the load is
>managable right now.
>
>Like I said, my decades of maintenance experience are saying that this
>isn't for routine maintenance. Brown Ottawa, sure. Brown Toronto, sure.
>Brown the entire province at once? They're seeing if they can thin the
>soup, because i think they forsee the day they're out of stock and
>they'll need to.
>
>Again, glad I'm not in Ontario...
>
>DJ
| |
|
|
Quite well documented - a 5 % province-wide voltage reduction
will reduce demand by about 2 % ( 500 MW during peak )
Most customers do not notice the reduction at all.
Regards.
>
>And are also interested in knowing if (or how much) it'll help. The
>days of linear loads are over, many loads will respond to a drop in
>voltage by increasing current to keep power continuous, and while they
>certainly realize that a 5% voltage reduction won't cut power
>consumption by 5%, they are probably interested in knowing by how much
>it will decrease, and if they'll run into other problems.
>
>It'll probably be painful for some small segment of the population,
>but they are way better off knowing the characteristics of their grid
>than just relying on engineering analyses.
| |
|
|
"SQLit" <sqlit@qwest.net> wrote in message
news:ZkPzf.29$8f.1584@news.uswest.net...
:
....
:
: I used to work around a server farm. The electrical system was
double
: redundant. A mistake was make the system worked perfectly, not
one load had
: a problem. The manager had us escorted to the property line by
the police.
: He called every person he could think of. They all asked the
same question,
: "Was anything hurt?"
....
lol, wha hop? Fall asleep in your c&c or something? Normally
I'd just take a pass, but that sounds intersting enough to ask
"HUH?". ;-] I think a buncha bytes disappeared into the ether
or something.
Regards,
Pop
PS Does double redundant mean twice or thrice failsafed? Just
curious.
| |
|
|
"DJ" <dj_macintyre@hotmail.com> wrote in message
news:1137690274.775458.301060@g44g2000cwa.googlegroups.com...
:
: SQLit wrote:
:
: > Not doing testing is irresponsible.
:
: Absolutely. But have you ever heard of intentionally browning
the
: entire province for a test?
: The only reason you would run that test is if you wanted it to
be an
: option later.
:
: DJ
:
Actually, the operation sounded pretty good to me. The "brownout"
wasn't really a brownout: It was within the specificed voltages
required to be delivered. I'd rather see the testing done and
weak links uncovered "at leisure" as opposed to during a period
when it mattered and the whole grid went to its knees because of
a lack of conditioning. With all the above ground wiring they
have, and considering the age of their systems in some places, I
think it's a great idea. I live just across the river from
Canada in even older, totally above ground wiring region, and
that would be valuable information to have here. We lose power
around here whenever someone just exhales too hard, let alone be
ready for emergencies. That's one of the reasons I stick around
the power & offgrid groups; lots of good info passes around.
Regards,
Pop
| |
|
|
"DJ" <dj_macintyre@hotmail.com> wrote in message
news:1137690131.305220.246110@g43g2000cwa.googlegroups.com...
>
> Pop wrote:
>
> Well, wrong on both counts, actually. I'm a Journeyman Millwright by
> trade, aka Industrial Maintenance Mechanic. I also hold an Electrical
> Contractor's licence, certified to install and maintain electricity
> generation equipment, from nuke plants to wind farms.
>
> If you wanted to do maintenance to an electrical system, there's not a
> reason in the world you would "brown" the entire province. I'm thinking
> that this test is to see that on days where consumption comes close to
> exceeding production, as it did several times last summer, if they can
> ever-so-slightly brown the grid to try to boost their supply. So,
> basically, watering down the soup to try to feed the family. This would
> probably be the best time of the year to do it, as the load is
> managable right now.
>
> Like I said, my decades of maintenance experience are saying that this
> isn't for routine maintenance. Brown Ottawa, sure. Brown Toronto, sure.
> Brown the entire province at once? They're seeing if they can thin the
> soup, because i think they forsee the day they're out of stock and
> they'll need to.
>
> Again, glad I'm not in Ontario...
>
> DJ
So are we
| |
| SolarFlair 2006-01-19, 9:21 pm |
| Hydro One (former HEP Ontario) has completely this 5%
voltage reduction many times looking for hardships
endured by industry.
Get this....there ain't any. Nobody was even the wiser
for years now. This time they preannounced it and took
flack all day for it. I viewed many of the local
industry's internal voltage today and most of them have
lower voltage when they have their load cranked up
during regular voltage sessions. Most of them whined
about how bad it was and no idead what they were
talking about.
It's all in the viewers heads and a necessary evil to
prevent major problems.
"DJ" <dj_macintyre@hotmail.com> wrote in message
news:1137700823.005914.270320@g43g2000cwa.googlegroups.com...
>
> William P.N. Smith wrote:
it'll help. The[color=darkred]
respond to a drop in[color=darkred]
continuous, and while they[color=darkred]
cut power[color=darkred]
knowing by how much[color=darkred]
problems.[color=darkred]
>
> That was my thought. How far can they go before
commercial
> refrigeration compressors and such start to overheat
because the amps
> went up because the volts went down...
>
the population,[color=darkred]
characteristics of their grid[color=darkred]
>
> Oh yeah, I agree, better to test now than to just do
it next August and
> cross their fingers. Well, knowing what I've heard
about Ontario Hydro
> from some experts and consultants I know, well, you
guys don't seem to
> want to think about it anyway ;-).
>
> DJ
>
| |
|
|
daestrom wrote:
>
> That's exactly what it is. But don't be so alarmist about it. Just about
> every ISO has done this sort of test (NY, PJM, NE... all of them).
I can believe that. But this is the first time they ever made a big
deal about it; you're right, had they not said anything, nobody would
have likely noticed. Still, struck me as very weird that they'd make an
announcement this time.
> You're off-grid, so you shouldn't really care.
I don't. Just thought it very odd that they'd make an announcement to
all the government branches and many local industrial customers this
time, when they never did before...
> You seem to be just trying to make yourself 'feel good' by ranting how
> unreliable Ontario power is going to be and that this somehow 'proves' they
> are planning for brownouts and that you made the 'right' choice to be
> off-grid. Are you that insecure in your decision?
Gawd no. They could run hydro right by the end of my driveway and I'd
still likely not hook up.
> Their preparations are probably going to make their grid *more* reliable.
>
> daestrom
Well, more predictable. Reliable is another story. But hey, if you guys
like the Emperor's Clothes, more "power" to you ;-).
DJ
| |
|
|
"DJ" <dj_macintyre@hotmail.com> wrote in message
news:1137678461.151215.12680@o13g2000cwo.googlegroups.com...
> Came across this announcement today, about today. Don't know about you,
> but *I* am awfully glad I'm not living on the Ontario grid. This does
> not bode well...
>
> Quote:
>
> The Ontario Independent Electricity System Operator (IESO) is planning
> a voltage
> reduction test for Thursday, January 19, 2006. The test will consist of
> two
> province-wide voltage reductions:
>
> 1. A reduction of 3%, from 9:30 EST to 11:00 EST, and
> 2. A reduction of 5%, from 17:30 EST to 19:30 EST.
>
> The purpose of the test is to establish and record the load reduction
> resulting from
> a system wide voltage reduction and to locate potential operational and
> customer
> problems that may occur. It is an important part of training for
> emergencies for
> the IESO and market participants.
Great idea, like the 55 mph speed limit in the US, until they realized it
took longer to get there with the same fuel.
Reducing voltage means the fridge runs 5% longer, the electric blanket is
turned up 5% higher and you need to turn on 2 lamps instead of one.
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[color=darkred]
>I can believe that. But this is the first time they ever made a big
>deal about it; you're right, had they not said anything, nobody would
>have likely noticed. Still, struck me as very weird that they'd make an
>announcement this time.
> Just thought it very odd that they'd make an announcement to
>all the government branches and many local industrial customers this
>time, when they never did before...
The electrical authorities have never kept these tests secret, in
any way - they have always publicly announced them in order to
track-down any voltage complaints and try to make corrections.
The media seemed to make a slightly-bigger-deal of this round of
tests, for some reason ... sick of election campaign, is my guess.
Regards
| |
|
|
> "JoeSP" wrote:
>Great idea, like the 55 mph speed limit in the US, until they realized it
>took longer to get there with the same fuel.
>Reducing voltage means the fridge runs 5% longer, the electric blanket is
>turned up 5% higher and you need to turn on 2 lamps instead of one.
In fact, the 3 % and 5 % voltage reduction
is an effective power system emergency control measure.
The household appliances do not seem to mind, at all.
I have yet to hear one voice any complaint.
Regards
| |
| daestrom 2006-01-20, 9:21 am |
|
"JoeSP" <olegp@telus.net> wrote in message
news:2z%zf.81362$m05.71363@clgrps12...
>
> "DJ" <dj_macintyre@hotmail.com> wrote in message
> news:1137678461.151215.12680@o13g2000cwo.googlegroups.com...
>
> Great idea, like the 55 mph speed limit in the US, until they realized it
> took longer to get there with the same fuel.
>
> Reducing voltage means the fridge runs 5% longer,
Not true, such a voltage reduction has no affect on refrigerator 'run time'.
The change in compressor speed would be imperceptible.
> the electric blanket is turned up 5% higher
Not true. Most electric blankets have a 'thermostat' that cycles them on
and off, so the amount of energy the blanket uses is controlled by the
temperature in the room and comfort of the user. May change the total
'on-time', but it won't change the amount of energy used.
>and you need to turn on 2 lamps instead of one.
Well, this one you're at least *close*. Lower voltage will reduce the lumen
output of the lamp. But it wouldn't be 1/2. In fact most folks wouldn't
even notice the reduction unless shown side-by-side.
daestrom
| |
|
|
_jj_ wrote:
> The electrical authorities have never kept these tests secret, in
> any way - they have always publicly announced them in order to
> track-down any voltage complaints and try to make corrections.
> The media seemed to make a slightly-bigger-deal of this round of
> tests, for some reason ... sick of election campaign, is my guess.
> Regards
Well, thing is, in my experience, they've never gotten this proactive
before. I spent ten years doing electrical and maintenance in a large
chemical plant in the Ottawa area, talked to the Hydro guys regularly
(we had some gear that needed their permission before we started it up
because we could brown the grid unless they were ready for it) and I've
never heard of them doing this before, yet they called that plant and
alerted them THIS time.
Could be that's just a local thing, and because of that, I was
surprised this time.
DJ
| |
| Derek Broughton 2006-01-20, 10:21 am |
| _jj_ wrote:
> The electrical authorities have never kept these tests secret, in
> any way - they have always publicly announced them in order to
> track-down any voltage complaints and try to make corrections.
> The media seemed to make a slightly-bigger-deal of this round of
> tests, for some reason ... sick of election campaign, is my guess.
LOL. I'd have to agree that's probably what it is. Here it is Friday, and
my car-pool partner was saying this morning "I can't wait for Monday". I
spent last weekend sick in bed, so I'm looking forward to a real weekend
and didn't get the point - which was that she's thoroughly sick of the
campaign and just wants it over.
--
derek
| |
|
|
Derek Broughton wrote:
> and didn't get the point - which was that she's thoroughly sick of the
> campaign and just wants it over.
Dunno if you guys actually care what happens on the Quebec side, but
for the first time in damn near recorded history the polls are saying
both the Gatineau and the Pontiac ridings are going to switch from Red
to Blue... or Bleu. And supposedly, if it's Blue, we get a cabinet seat
for the Pontiac, or so Harper promised.
But yep, it's been long enough. Just do it already ;-).
DJ
| |
|
|
....
:
: Great idea, like the 55 mph speed limit in the US, until they
realized it
: took longer to get there with the same fuel.
:
: Reducing voltage means the fridge runs 5% longer, the electric
blanket is
: turned up 5% higher and you need to turn on 2 lamps instead of
one.
:
:
LOL, nice try anyway!
| |
|
|
"SolarFlair" <sf@hot.mail.invalid> wrote in message
news:J_CdncMTtOaTr03enZ2dnUVZ_tadnZ2d@golden.net...
: Hydro One (former HEP Ontario) has completely this 5%
: voltage reduction many times looking for hardships
: endured by industry.
....
:
: It's all in the viewers heads and a necessary evil to
: prevent major problems.
:
....
Please, no jokes this time of day, OK?
| |
| clare at snyder.on.ca 2006-01-21, 4:21 pm |
| X-Newsreader: Forte Agent 1.91/32.564
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit
Lines: 45
NNTP-Posting-Date: 21 Jan 2006 19:23:27 GMT
X-Complaints-To: abuse@nntpserver.com
Xref: number1.nntp.dca.giganews.com alt.energy.homepower:123944
On 19 Jan 2006 16:54:36 -0800, "DJ" <dj_macintyre@hotmail.com> wrote:
>
>daestrom wrote:
>
>
>I can believe that. But this is the first time they ever made a big
>deal about it; you're right, had they not said anything, nobody would
>have likely noticed. Still, struck me as very weird that they'd make an
>announcement this time.
>
>
>I don't. Just thought it very odd that they'd make an announcement to
>all the government branches and many local industrial customers this
>time, when they never did before...
>
>
>Gawd no. They could run hydro right by the end of my driveway and I'd
>still likely not hook up.
>
>
>Well, more predictable. Reliable is another story. But hey, if you guys
>like the Emperor's Clothes, more "power" to you ;-).
>
>DJ
Other than management being in-efficient and costs being somewhat out
of control, Ontario has a pretty darn good Hydro system. The Candu
reactors work well when they are online, but have proven to be rather
expensive to refurbish - likely mostly due to "political realities" -
now THAT is an OxyMoron if I ever heard one.
| |
| Mr Wizzard 2006-01-22, 2:21 am |
|
"_jj_" <NOSPAMtabbertj@NOSPAMperth.net> wrote in message
news:al40t1517oq25ii1i59to6u0l70sta2c4l@4ax.com...
>
> Quite well documented - a 5 % province-wide voltage reduction
> will reduce demand by about 2 % ( 500 MW during peak )
> Most customers do not notice the reduction at all.
Don't most electronics (switching power supplies etc) just
hand up drawing more current when the voltage drops ?
Or is the bulk of all average draw comprised mostly of
resistive load, and inductive (and rotating inductive) ?
> Regards.
>
>
>
| |
|
|
"Mr Wizzard" <wiz@muffy-mail.com> wrote in message
news:-NmdnVZO_tYqiE7enZ2dnUVZ_vmdnZ2d@comcast.com...
:
: "_jj_" <NOSPAMtabbertj@NOSPAMperth.net> wrote in message
: news:al40t1517oq25ii1i59to6u0l70sta2c4l@4ax.com...
: >
: > Quite well documented - a 5 % province-wide voltage
reduction
: > will reduce demand by about 2 % ( 500 MW during peak )
: > Most customers do not notice the reduction at all.
:
: Don't most electronics (switching power supplies etc) just
: hand up drawing more current when the voltage drops ?
Yes, for the most part. Within their specs, lowering the voltage
on other than resistive loads increases the current draw in an
attempt to keep the wattage near constant.
: Or is the bulk of all average draw comprised mostly of
: resistive load, and inductive (and rotating inductive) ?
Inductive (rotating devices) draw more current as the voltage
drops. That's why excessively low voltages can burn out electric
motors, I'm pretty sure; the excessive current creates too much
heat in the windings.
:
That all probably explains why a 5% voltage reduction only
results in a 2% demand drop. If the load was purely resistive,
the 2% would be closer to 5%.
HTH,
Pop
:
:
: > Regards.
: >
: >
: > >
: > >And are also interested in knowing if (or how much) it'll
help. The
: > >days of linear loads are over, many loads will respond to a
drop in
: > >voltage by increasing current to keep power continuous, and
while they
: > >certainly realize that a 5% voltage reduction won't cut
power
: > >consumption by 5%, they are probably interested in knowing
by how much
: > >it will decrease, and if they'll run into other problems.
: > >
: > >It'll probably be painful for some small segment of the
population,
: > >but they are way better off knowing the characteristics of
their grid
: > >than just relying on engineering analyses.
: >
:
:
| |
| daestrom 2006-01-22, 1:21 pm |
|
"Pop" <nobody@devnull.spamcop.net> wrote in message
news:TzNAf.18995$La4.14375@trndny08...
>
> "Mr Wizzard" <wiz@muffy-mail.com> wrote in message
> news:-NmdnVZO_tYqiE7enZ2dnUVZ_vmdnZ2d@comcast.com...
> :
> : "_jj_" <NOSPAMtabbertj@NOSPAMperth.net> wrote in message
> : news:al40t1517oq25ii1i59to6u0l70sta2c4l@4ax.com...
> : >
> : > Quite well documented - a 5 % province-wide voltage
> reduction
> : > will reduce demand by about 2 % ( 500 MW during peak )
> : > Most customers do not notice the reduction at all.
> :
> : Don't most electronics (switching power supplies etc) just
> : hand up drawing more current when the voltage drops ?
>
> Yes, for the most part. Within their specs, lowering the voltage
> on other than resistive loads increases the current draw in an
> attempt to keep the wattage near constant.
>
> : Or is the bulk of all average draw comprised mostly of
> : resistive load, and inductive (and rotating inductive) ?
>
> Inductive (rotating devices) draw more current as the voltage
> drops. That's why excessively low voltages can burn out electric
> motors, I'm pretty sure; the excessive current creates too much
> heat in the windings.
> :
> That all probably explains why a 5% voltage reduction only
> results in a 2% demand drop.
Right.
> If the load was purely resistive,
> the 2% would be closer to 5%.
>
Actually, with purely resistive loads, a voltage of 95% of nominal would
yield a power of 0.95^2 =>~90% of nominal. So the fact that it was only 2%
shows that load is not all resistive in nature.
daestrom
| |
| danny burstein 2006-01-22, 2:21 pm |
| In <TzNAf.18995$La4.14375@trndny08> "Pop" <nobody@devnull.spamcop.net> writes:
[ snip ]
>That all probably explains why a 5% voltage reduction only
>results in a 2% demand drop. If the load was purely resistive,
>the 2% would be closer to 5%.
Acually could be worse (or better, depending on whic side
of the equation you are...).
A five percent drop in voltage, into a stable resistance [a], means
you'll also get a corresponding five percent drop in amperage.
This leads to a (0.95 * 0.95 ) 0.9025, or 90 percent, wattage
throughput - a nearly 10 percent change.
This becomes annoyingly apparen not only in lighting, but
also in such things as ovens and tea kettles - which will
take 10 percent longer [b]. It's even worse when using
an electric heating element as a "broiler", since it won't
get as hot and won't radiate as much.
[a] hard to tell without lots more info what the exact
effect would be on incandescent lamps and eating strips,
since their resistance does vary with temperature.
[b] there's a specific voltage supply issue in the US
(don't know about other parts of the world power grid)
where the "normal" household voltage is a single
phase 120VAC, with high wattage items pulling 240VAC.
The latter would include, for example, electric stoves/ovens,
large air conditioners, electric dryers, etc.
The problem: the 240V figure is derived by using both
legs of a 120V transformer (that is, each leg is 120V
to ground, but they are 240V measured against each other).
HOWEVER: in many circuits the higher voltage outlet
is powered by two (of the three) legs of a three phase
circuit, giving you a derived 208VAC in it.
While most (certainly NOT all) 240V appliances will work
ok at the 208V figure, motors either derate or pull more
current (or both...) and heating appliances show a
marked reduction.
Note that 208 is only 0.8666 (86 percent) of the nominal 240V,
so the actual wattage is (0.866 * 0.866 ) only 75 percent.
--
_____________________________________________________
Knowledge may be power, but communications is the key
dannyb@panix.com
[to foil spammers, my address has been double rot-13 encoded]
| |
| Mr Wizzard 2006-01-22, 2:21 pm |
|
"Pop" <nobody@devnull.spamcop.net> wrote in message
news:TzNAf.18995$La4.14375@trndny08...
>
> "Mr Wizzard" <wiz@muffy-mail.com> wrote in message
> news:-NmdnVZO_tYqiE7enZ2dnUVZ_vmdnZ2d@comcast.com...
> :
> : "_jj_" <NOSPAMtabbertj@NOSPAMperth.net> wrote in message
> : news:al40t1517oq25ii1i59to6u0l70sta2c4l@4ax.com...
> : >
> : > Quite well documented - a 5 % province-wide voltage
> reduction
> : > will reduce demand by about 2 % ( 500 MW during peak )
> : > Most customers do not notice the reduction at all.
> :
> : Don't most electronics (switching power supplies etc) just
> : hand up drawing more current when the voltage drops ?
>
> Yes, for the most part. Within their specs, lowering the voltage
> on other than resistive loads increases the current draw in an
> attempt to keep the wattage near constant.
>
> : Or is the bulk of all average draw comprised mostly of
> : resistive load, and inductive (and rotating inductive) ?
>
> Inductive (rotating devices) draw more current as the voltage
> drops.
Current draw is proportional to "slip angle", and so if slip angle
is maintained, (for a given voltage), the current draw will be
proportional to the drop in voltage (not inversely proportional).
If the design of the load, (and motor capacity curve) moves the
slip angle an inordinate amount during a 5-10% voltage drop,
then yeah, there will be an element of current/voltage "inverse"
proportionality, but I would think that this would mainly only
manifest itself in "startup" situations (locked rotor to sync speed),
startup windings, head pressures in A/C compressors, and such.
> That's why excessively low voltages can burn out electric
> motors, I'm pretty sure; the excessive current creates too much
> heat in the windings.
High(er) currents increase IR losses (copper losses) which
results in heat, yes so long as the symmetry of the wave is maintained.
But again, it gets down to rotor speed, and the resultant change
in the "slip angle". You'd really have to "know" how much (if any)
the slip angle changes in the voltage reduction situation to determine
how much the current would become non-proportional.
> :
> That all probably explains why a 5% voltage reduction only
> results in a 2% demand drop. If the load was purely resistive,
> the 2% would be closer to 5%.
But its a mix. Splitting hairs, yes, but it is fun to think about.
>
> HTH,
>
> Pop
> :
> :
> : > Regards.
> : >
> : >
> : > >
> : > >And are also interested in knowing if (or how much) it'll
> help. The
> : > >days of linear loads are over, many loads will respond to a
> drop in
> : > >voltage by increasing current to keep power continuous, and
> while they
> : > >certainly realize that a 5% voltage reduction won't cut
> power
> : > >consumption by 5%, they are probably interested in knowing
> by how much
> : > >it will decrease, and if they'll run into other problems.
> : > >
> : > >It'll probably be painful for some small segment of the
> population,
> : > >but they are way better off knowing the characteristics of
> their grid
> : > >than just relying on engineering analyses.
> : >
> :
> :
>
>
| |
| Solar Flare 2006-01-22, 4:21 pm |
| Our town decidedly allows 125/216 volts as an
acceptable compromise of both voltages on residential
customers where load density is high. (called "Network"
services) It reduces the amount of copper usage in
large apartment buildings etc..
208 volts is for three phase appliances that are
usually designed for that voltage.
"danny burstein" <dannyb@panix.com> wrote in message
news:dr0g8c$gmb$1@reader2.panix.com...
> In <TzNAf.18995$La4.14375@trndny08> "Pop"
<nobody@devnull.spamcop.net> writes:
> is powered by two (of the three) legs of a three
phase
> circuit, giving you a derived 208VAC in it.
>
> While most (certainly NOT all) 240V appliances will
work
> ok at the 208V figure, motors either derate or pull
more
> current (or both...) and heating appliances show a
> marked reduction.
>
> Note that 208 is only 0.8666 (86 percent) of the
nominal 240V,
> so the actual wattage is (0.866 * 0.866 ) only 75
percent.
>
>
>
> --
> _____________________________________________________
> Knowledge may be power, but communications is the key
> dannyb@panix.com
> [to foil spammers, my address has been double rot-13
encoded]
| |
| clare at snyder.on.ca 2006-01-22, 4:21 pm |
| On Sun, 22 Jan 2006 17:43:40 +0000 (UTC), danny burstein
<dannyb@panix.com> wrote:
>In <TzNAf.18995$La4.14375@trndny08> "Pop" <nobody@devnull.spamcop.net> writes:
> [ snip ]
>
>
>Acually could be worse (or better, depending on whic side
>of the equation you are...).
>
>A five percent drop in voltage, into a stable resistance [a], means
>you'll also get a corresponding five percent drop in amperage.
>
>This leads to a (0.95 * 0.95 ) 0.9025, or 90 percent, wattage
>throughput - a nearly 10 percent change.
>
>This becomes annoyingly apparen not only in lighting, but
>also in such things as ovens and tea kettles - which will
>take 10 percent longer [b]. It's even worse when using
>an electric heating element as a "broiler", since it won't
>get as hot and won't radiate as much.
>
>[a] hard to tell without lots more info what the exact
>effect would be on incandescent lamps and eating strips,
>since their resistance does vary with temperature.
>
>[b] there's a specific voltage supply issue in the US
>(don't know about other parts of the world power grid)
>where the "normal" household voltage is a single
>phase 120VAC, with high wattage items pulling 240VAC.
>
>The latter would include, for example, electric stoves/ovens,
>large air conditioners, electric dryers, etc.
>
>The problem: the 240V figure is derived by using both
>legs of a 120V transformer (that is, each leg is 120V
>to ground, but they are 240V measured against each other).
>
>HOWEVER: in many circuits the higher voltage outlet
>is powered by two (of the three) legs of a three phase
>circuit, giving you a derived 208VAC in it.
>
>While most (certainly NOT all) 240V appliances will work
>ok at the 208V figure, motors either derate or pull more
>current (or both...) and heating appliances show a
>marked reduction.
>
>Note that 208 is only 0.8666 (86 percent) of the nominal 240V,
>so the actual wattage is (0.866 * 0.866 ) only 75 percent.
But 208 is ONLY found in industrial or large commercial installations.
Virtually no residential supplies are derived from 3 phase. Most 3
phase derived supplies to single phase loads are "upped" by
transformers (buck/boost or full isolation) to the standard 115 or
230.
| |
|
| William P.N. Smith wrote:
> "DJ" <dj_macintyre@hotmail.com> wrote:
>
>
>
> And are also interested in knowing if (or how much) it'll help. The
> days of linear loads are over, many loads will respond to a drop in
> voltage by increasing current to keep power continuous, and while they
> certainly realize that a 5% voltage reduction won't cut power
> consumption by 5%, they are probably interested in knowing by how much
> it will decrease, and if they'll run into other problems.
Indeed. And switching power supplies probably improve their power
factor, which could benefit the grid.
>
> It'll probably be painful for some small segment of the population,
> but they are way better off knowing the characteristics of their grid
> than just relying on engineering analyses.
--
The e-mail address in our reply-to line is reversed in an attempt to
minimize spam. Our true address is of the form che...@prodigy.net.
| |
| Solar Flare 2006-01-22, 9:21 pm |
| Not here in central Ontario. Most of our large
apartment buildings are 125/216 network services.
The electricians like it 'cause it saves copper bus
running through the building.
<clare at snyder.on.ca> wrote in message
news:qdp7t11adhodhlqcv1m6h58k2h55rbmmj5@4ax.com...
> On Sun, 22 Jan 2006 17:43:40 +0000 (UTC), danny
burstein
> <dannyb@panix.com> wrote:
>
<nobody@devnull.spamcop.net> writes:[color=darkred]
reduction only[color=darkred]
purely resistive,[color=darkred]
side[color=darkred]
resistance [a], means[color=darkred]
amperage.[color=darkred]
percent, wattage[color=darkred]
lighting, but[color=darkred]
will[color=darkred]
using[color=darkred]
won't[color=darkred]
exact[color=darkred]
strips,[color=darkred]
US[color=darkred]
grid)[color=darkred]
240VAC.[color=darkred]
stoves/ovens,[color=darkred]
both[color=darkred]
120V[color=darkred]
other).[color=darkred]
phase[color=darkred]
work[color=darkred]
more[color=darkred]
nominal 240V,[color=darkred]
percent.[color=darkred]
>
> But 208 is ONLY found in industrial or large
commercial installations.
> Virtually no residential supplies are derived from 3
phase. Most 3
> phase derived supplies to single phase loads are
"upped" by
> transformers (buck/boost or full isolation) to the
standard 115 or
> 230.
| |
|
| In article <qdp7t11adhodhlqcv1m6h58k2h55rbmmj5@4ax.com>,
clare at snyder.on.ca wrote:
> Virtually no residential supplies are derived from 3 phase.
Well now this is blattantly not true...All Commercial Grid Power
is MultiPhase in nature. If one would actually LOOK at the
Transmission System, one would notice that from Generation
clear down to the local Distribution Substation, ALL power
is conducted by MultiPhase Transmission Lines. From the last
SubStation to your residentail feed is done with 3 Phase lines.
Down your block, may actually only be one Phase of one of
those 3 Phase Feeders, but the only Single Phase Transformer
in the whole system is the one on top of your local pole.
You vary well could have 3 Phase Distribution on your local
pole, with your PolePig only being connected to one Phase
and neutral.
me
| |
| daestrom 2006-01-23, 6:21 pm |
|
"Mr Wizzard" <wiz@muffy-mail.com> wrote in message
news:5aadnZqZTKnKVE7eRVn-iQ@comcast.com...
>
> "Pop" <nobody@devnull.spamcop.net> wrote in message
> news:TzNAf.18995$La4.14375@trndny08...
>
> Current draw is proportional to "slip angle", and so if slip angle
> is maintained, (for a given voltage), the current draw will be
> proportional to the drop in voltage (not inversely proportional).
> If the design of the load, (and motor capacity curve) moves the
> slip angle an inordinate amount during a 5-10% voltage drop,
> then yeah, there will be an element of current/voltage "inverse"
> proportionality, but I would think that this would mainly only
> manifest itself in "startup" situations (locked rotor to sync speed),
> startup windings, head pressures in A/C compressors, and such.
>
Actually, just about any induction motor will do this while running. The
power draw is a function of the torque demanded by the load at the present
speed. And because of the shape of the speed/torque curve for almost all
induction motors is very 'steep' near the normal operating point, the power
demanded of the load changes very little for the minor variations of slip
that occur around the normal operating point.
The issue gets interesting when you start dealing with partially loaded
machines. Although the 'real' component of current *must* increase with
voltage reduction (first law issue), the 'imaginary' component may increase
or decrease. That is, while the slip must increase so that real current
increases to maintain an energy flow balance, the power factor may actually
improve in partially loaded machines, causing the overall current to
decrease. Fully loaded machines, on the other hand, will usually experience
a drop in power factor at off-normal voltages, necessitating a further
increase in current beyond the simple inverse proportionality.
>
> High(er) currents increase IR losses (copper losses) which
> results in heat, yes so long as the symmetry of the wave is maintained.
> But again, it gets down to rotor speed, and the resultant change
> in the "slip angle". You'd really have to "know" how much (if any)
> the slip angle changes in the voltage reduction situation to determine
> how much the current would become non-proportional.
>
daestrom
P.S. There really isn't such a term as 'slip angle'. In induction motor
theory, 'slip' is defined as (synchspeed - rotorspeed) / synchspeed. It is
a 'normalized ratio', not an 'angle'. Perhaps you're confusing this with
'power angle' that is significant in power transmission over an AC line, or
'torque angle' that is the angle between the rotor and stator fields in a
*synchronous* machine.
| |
| Solar Flare 2006-01-23, 9:21 pm |
| Or
In the back or front yard in your neighbourhood. We
arent barbarians in Ontario
LOL
"Me" <Me@shadow.orgs> wrote in message
news:Me-E46A2D.10192623012006@netnews.worldnet.att.net...
> In article
<qdp7t11adhodhlqcv1m6h58k2h55rbmmj5@4ax.com>,
> Down your block, may actually only be one Phase of
one of
> those 3 Phase Feeders, but the only Single Phase
Transformer
> in the whole system is the one on top of your local
pole.
> You vary well could have 3 Phase Distribution on your
local
> pole, with your PolePig only being connected to one
Phase
> and neutral.
>
> me
| |
| clare at snyder.on.ca 2006-01-23, 10:21 pm |
| On Mon, 23 Jan 2006 19:17:49 GMT, Me <Me@shadow.orgs> wrote:
>In article <qdp7t11adhodhlqcv1m6h58k2h55rbmmj5@4ax.com>,
> clare at snyder.on.ca wrote:
>
>
>Well now this is blattantly not true...All Commercial Grid Power
>is MultiPhase in nature. If one would actually LOOK at the
>Transmission System, one would notice that from Generation
>clear down to the local Distribution Substation, ALL power
>is conducted by MultiPhase Transmission Lines. From the last
>SubStation to your residentail feed is done with 3 Phase lines.
>Down your block, may actually only be one Phase of one of
>those 3 Phase Feeders, but the only Single Phase Transformer
>in the whole system is the one on top of your local pole.
>You vary well could have 3 Phase Distribution on your local
>pole, with your PolePig only being connected to one Phase
>and neutral.
>
>me
They are DISTRIBUTED 3 phase, but not DERIVED from 3 phase. With the
exception of MURBs there is virtually no 3 phase or 208 in residential
use in Ontario. And there is a lot less 208 being used even in MURBs
than there used to be.
| |
| clare at snyder.on.ca 2006-01-23, 10:21 pm |
| On Mon, 23 Jan 2006 19:32:08 -0500, "Solar Flare"
<sfl@hutmail.notvalid> wrote:
>Or
>In the back or front yard in your neighbourhood. We
>arent barbarians in Ontario
>
>LOL
>
>"Me" <Me@shadow.orgs> wrote in message
>news:Me-E46A2D.10192623012006@netnews.worldnet.att.net...
><qdp7t11adhodhlqcv1m6h58k2h55rbmmj5@4ax.com>,
>one of
>Transformer
>pole.
>local
>Phase
>
No "pole pigs" within about 4 miles of my place - all underground
services so ice storms and wind storms etc do less damage (not to
mentionthe streetscapes are MUCH cleaner)
| |
| Mr Wizzard 2006-01-24, 6:21 am |
|
"daestrom" <daestrom@NO_SPAM_HEREtwcny.rr.com> wrote in message
news:vfcBf.101867$XJ5.57462@twister.nyroc.rr.com...
>
> "Mr Wizzard" <wiz@muffy-mail.com> wrote in message
> news:5aadnZqZTKnKVE7eRVn-iQ@comcast.com...
>
> Actually, just about any induction motor will do this while running. The
> power draw is a function of the torque demanded by the load at the present
> speed. And because of the shape of the speed/torque curve for almost all
> induction motors is very 'steep' near the normal operating point, the
power
> demanded of the load changes very little for the minor variations of slip
> that occur around the normal operating point.
>
> The issue gets interesting when you start dealing with partially loaded
> machines. Although the 'real' component of current *must* increase with
> voltage reduction (first law issue), the 'imaginary' component may
increase
> or decrease. That is, while the slip must increase so that real current
> increases to maintain an energy flow balance, the power factor may
actually
> improve in partially loaded machines, causing the overall current to
> decrease. Fully loaded machines, on the other hand, will usually
experience
> a drop in power factor at off-normal voltages, necessitating a further
> increase in current beyond the simple inverse proportionality.
>
>
> daestrom
>
> P.S. There really isn't such a term as 'slip angle'. In induction motor
> theory, 'slip' is defined as (synchspeed - rotorspeed) / synchspeed. It
is
> a 'normalized ratio', not an 'angle'.
> Perhaps you're confusing this with
> 'power angle' that is significant in power transmission over an AC line,
or
> 'torque angle' that is the angle between the rotor and stator fields in a
> *synchronous* machine.
No, I'm not confusing "slip" with power/torque angles.
Quote from an application note :
" In AC asynchronous motors, a rotating field is
induced in the rotor, which causes it to rotate
in the same direction of the stator field but at
a slower angular frequency. The difference in these
frequencies is called "slip frequency"
and the angle between them the "slip angle."
A similar article appeared in the June 2000
issue of Sensors "
But I do understand slip as a "percentage"
in an induction motor too. I also realize that
we're not really talking about VVVF motors
where the air gap flux (in volts per Hertz)
changes linierly, so yeah. With appliance
motors, we're also talking about rotors
with fairly high rotor bar impeadance too.
>
>
| |
|
| In article <h73bt1dk05ngl14dhoeqapfb9o5fr6qm40@4ax.com>,
clare at snyder.on.ca wrote:
> No "pole pigs" within about 4 miles of my place - all underground
> services so ice storms and wind storms etc do less damage (not to
> mentionthe streetscapes are MUCH cleaner)
so you have "GroundPigs".....what eles is new......
Me
| |
| Gordon Richmond 2006-01-24, 11:21 pm |
| And if the Ontario grid is browned out today, you ca blame it on all
the paper shredders in Ottawa running non-stop.
Gordon Richmond
| |
| clare at snyder.on.ca 2006-01-24, 11:21 pm |
| On Tue, 24 Jan 2006 20:21:36 GMT, Me <Me@shadow.orgs> wrote:
>In article <h73bt1dk05ngl14dhoeqapfb9o5fr6qm40@4ax.com>,
> clare at snyder.on.ca wrote:
>
>
>so you have "GroundPigs".....what eles is new......
>
>Me
Only problem is, after a good heavy rain they sometimes turn i to "hog
wallers" and short out.
| |
| Solar Flare 2006-01-24, 11:21 pm |
| LOL. Just about it too.
"Gordon Richmond" <richmond@telusplanet.net> wrote in
message
news:lopdt1ld5r13526b52ahs1vcuiuhbtlsfm@4ax.com...
> And if the Ontario grid is browned out today, you ca
blame it on all
> the paper shredders in Ottawa running non-stop.
>
> Gordon Richmond
| |
| daestrom 2006-01-25, 9:21 pm |
|
"Mr Wizzard" <wiz@muffy-mail.com> wrote in message
news:R6udnZTbfteIZ0jeRVn-gg@comcast.com...
>
> "daestrom" <daestrom@NO_SPAM_HEREtwcny.rr.com> wrote in message
> news:vfcBf.101867$XJ5.57462@twister.nyroc.rr.com...
> power
> increase
> actually
> experience
> is
>
> or
>
> No, I'm not confusing "slip" with power/torque angles.
>
> Quote from an application note :
>
> " In AC asynchronous motors, a rotating field is
> induced in the rotor, which causes it to rotate
> in the same direction of the stator field but at
> a slower angular frequency. The difference in these
> frequencies is called "slip frequency"
> and the angle between them the "slip angle."
> A similar article appeared in the June 2000
> issue of Sensors "
>
Don't know what 'application note' you read that from, but it is wrong. The
rotor's magnetic field rotates at *exactly* syncronous speed. But since the
rotor itself does not, that means the magnetic field is moving 'forward'
around the rotor surface. If the magnetic field on the rotor did *not*
rotate at sync speed, then the torque it would develop would alternate
forward and backward as the stator field periodically overtook the rotor
field.
The 'slip frequency' is the frequency of the voltage/current induced in the
rotor bars. This is caused by the bars moving slower than the stator
magnetic field. But when you take the rotor speed (speed of the moving
bars), and then 'add' on the slip frequency to find the speed of the
rotor's magnetic field (speed of the rotor's rotating magnetic field with
reference to those rotor bars that are carrying current), "voila", you're
right back to synchronous speed.
Don't believe, me, go over to 'alt.engineering.electrical' and ask them.
daestrom
| |
| Mr Wizzard 2006-01-26, 5:21 am |
|
"daestrom" <daestrom@NO_SPAM_HEREtwcny.rr.com> wrote in message
news:jLUBf.144483$XC4.128380@twister.nyroc.rr.com...
>
> "Mr Wizzard" <wiz@muffy-mail.com> wrote in message
> news:R6udnZTbfteIZ0jeRVn-gg@comcast.com...
The[color=darkred]
all[color=darkred]
slip[color=darkred]
with[color=darkred]
current[color=darkred]
maintained.[color=darkred]
determine[color=darkred]
motor[color=darkred]
It[color=darkred]
line,[color=darkred]
a[color=darkred]
>
> Don't know what 'application note' you read that from, but it is wrong.
Wrong ??
> The rotor's magnetic field rotates at *exactly* syncronous speed. But
since the
> rotor itself does not, that means the magnetic field is moving 'forward'
> around the rotor surface. If the magnetic field on the rotor did *not*
> rotate at sync speed, then the torque it would develop would alternate
> forward and backward as the stator field periodically overtook the rotor
> field.
>
> The 'slip frequency' is the frequency of the voltage/current induced in
the
> rotor bars. This is caused by the bars moving slower than the stator
> magnetic field. But when you take the rotor speed (speed of the moving
> bars), and then 'add' on the slip frequency to find the speed of the
> rotor's magnetic field (speed of the rotor's rotating magnetic field with
> reference to those rotor bars that are carrying current), "voila", you're
> right back to synchronous speed.
>
> Don't believe, me, go over to 'alt.engineering.electrical' and ask them.
re-read that quote I posted from that App Note - you are both
saying the same thing.
>
> daestrom
>
>
| |
| daestrom 2006-01-26, 6:21 pm |
|
"Mr Wizzard" <wiz@muffy-mail.com> wrote in message
news:W4GdnaenNfktEEXenZ2dnUVZ_s-dnZ2d@comcast.com...
>
> "daestrom" <daestrom@NO_SPAM_HEREtwcny.rr.com> wrote in message
> news:jLUBf.144483$XC4.128380@twister.nyroc.rr.com...
> The
> all
> slip
> with
> current
> maintained.
> determine
> motor
> It
> line,
> a
> Wrong ??
Yes, it claims the two magnetic fields rotate at different angular
frequencies, and that is wrong.
>
> since the
>
> the
>
> re-read that quote I posted from that App Note - you are both
> saying the same thing.
>
I did re-read that quote and it is not saying the same thing as what I
posted. It states, quite clearly, "a rotating field is induced in the
rotor, which causes it to rotate in the same direction of the stator field
but at a slower angular frequency."
The magnetic field in the rotor does *not* rotate at a lower angular
frequency. It rotates at *exactly* the same angular frequency as the stator
magnetic field.
Further more, it goes on to say the 'The difference in these frequencies is
called "slip frequency" and the angle between them the "slip angle." ' Now,
if the two fields are running at different frequencies, how do you measure
this supposed "slip angle"? The displacement between two similar, but not
exactly equal angular frequencies is constantly changing. The relative
displacement will vary forward and backward with a frequency equal to the
difference between the two frequencies being compared.
There *is* a displacement between the field on the stator and the one on the
rotor, but that is not called 'slip angle', it is the 'torque angle' and is
responsible for generating a torque on the rotor to keep it spinning.
Because the two fields are at *exactly* the same angular frequency, the
'torque angle' is a constant value (for a given motor load).
daestrom
| |
| Mr Wizzard 2006-01-27, 2:21 am |
|
"daestrom" <daestrom@NO_SPAM_HEREtwcny.rr.com> wrote in message
news:l7bCf.115986$ME5.107926@twister.nyroc.rr.com...
>
> "Mr Wizzard" <wiz@muffy-mail.com> wrote in message
> news:W4GdnaenNfktEEXenZ2dnUVZ_s-dnZ2d@comcast.com...
almost[color=darkred]
the[color=darkred]
further[color=darkred]
>
> Yes, it claims the two magnetic fields rotate at different angular
> frequencies, and that is wrong.
>
'forward'[color=darkred]
rotor[color=darkred]
with[color=darkred]
you're[color=darkred]
them.[color=darkred]
>
> I did re-read that quote and it is not saying the same thing as what I
> posted. It states, quite clearly, "a rotating field is induced in the
> rotor, which causes it to rotate in the same direction of the stator field
> but at a slower angular frequency."
>
> The magnetic field in the rotor does *not* rotate at a lower angular
> frequency. It rotates at *exactly* the same angular frequency as the
stator
> magnetic field.
I think when he says "causes *it* ", and "at at slower",
he is refering to the rotor, not the field. (as the term
"slower" is not a term normally associated with frequency,
but rather a mechanical object.
>
> Further more, it goes on to say the 'The difference in these frequencies
is
> called "slip frequency" and the angle between them the "slip angle." '
Now,
> if the two fields are running at different frequencies, how do you measure
> this supposed "slip angle"? The displacement between two similar, but not
> exactly equal angular frequencies is constantly changing. The relative
> displacement will vary forward and backward with a frequency equal to the
> difference between the two frequencies being compared.
>
> There *is* a displacement between the field on the stator and the one on
the
> rotor, but that is not called 'slip angle', it is the 'torque angle' and
is
> responsible for generating a torque on the rotor to keep it spinning.
> Because the two fields are at *exactly* the same angular frequency, the
> 'torque angle' is a constant value (for a given motor load).
>
> daestrom
>
>
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|
| Was just at a seminar on grid-tie "stuff" down in near Toronto, lots
of component folks there, local experts in solar and such, and the
topic of this voltage reduction experiment came up.
I learned that the major effect of the province wide test was that
grid-tied systems all over the province shut down their export function
during the test, because the grid voltage was no longer in the very
tight operating range required by the utilities.
Too funny ;-).
DJ
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