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Harmonics in pole power transformers?

Started by Joerg April 17, 2016
On 2016-04-18 14:49, George Herold wrote:
> On Monday, April 18, 2016 at 4:09:48 PM UTC-4, Joerg wrote: >> On 2016-04-18 09:41, Adrian Tuddenham wrote: >>> Joerg <news@analogconsultants.com> wrote: >>> >>>> Folks, >>>> >>>> A system needs to be able to detect whether a pole transformer has >>>> failed and stopped feeding power to a pump. The transformer will be >>>> 100ft or more away. The detection has to work even without any power >>>> flow meaning we can only detect the presence of a 60Hz electric field >>>> that leaks from the various boxs such as a breaker box. >>>> >>>> In order not to get fooled by 60Hz from other overhead lines I was >>>> wondering if classic pole transformers generate enough 3rd and 5th >>>> harmonics to distinguish the field emanating from secondary wires from >>>> that coming from overhead HV lines. Does anyone know where to find info >>>> about that? >>> >>> Put a small strip of double-sided PC board between the power conductors >>> coming into the breaker box and wrap earthed foil around the outside of >>> the conductors for a short distance each side of it. A high-impedance >>> differential op-amp would detect the voltage difference between the two >>> sides of the board when there was a voltage difference between the two >>> conductors, but would be unaffected by common-mode voltages or an >>> external field. >>> >>> (With slightly changed geometry, this could be used as an undetectable >>> telephone-tapping device.) >>> >> >> That would require an electrician to come out and most would refuse this >> job because they, their employer or their union won't allow non-standard >> stuff. >> >> -- >> Regards, Joerg >> >> http://www.analogconsultants.com/ > > I'm not sure what requires an electrician. > But can't you stick some similar gizmo around the wires > going to the pump and sense the E-field. > (I guess if it's coax it's a lot harder.) >
You'd have to open the fuse panel of the breaker box to get that double-sided board inbetween. It is illegal in most jurisdictions for anyone to do that unless he or she is a licensed electrician. -- Regards, Joerg http://www.analogconsultants.com/
On 2016-04-18 14:56, Lasse Langwadt Christensen wrote:
> Den mandag den 18. april 2016 kl. 23.38.08 UTC+2 skrev Joerg: >> On 2016-04-18 14:19, Lasse Langwadt Christensen wrote: >>> Den s&#2013266168;ndag den 17. april 2016 kl. 22.54.36 UTC+2 skrev Joerg: >>>> Folks, >>>> >>>> A system needs to be able to detect whether a pole transformer has >>>> failed and stopped feeding power to a pump. The transformer will be >>>> 100ft or more away. The detection has to work even without any power >>>> flow meaning we can only detect the presence of a 60Hz electric field >>>> that leaks from the various boxs such as a breaker box. >>>> >>>> In order not to get fooled by 60Hz from other overhead lines I was >>>> wondering if classic pole transformers generate enough 3rd and 5th >>>> harmonics to distinguish the field emanating from secondary wires from >>>> that coming from overhead HV lines. Does anyone know where to find info >>>> about that? >>>> >>>> -- >>>> Regards, Joerg >>>> >>>> http://www.analogconsultants.com/ >>> >>> electrical-testers/fluke-2ac-electrical-tester.html >>> >> >> http://en-us.fluke.com/products/electrical-testers/fluke-2ac-electrical-tester.html#resources >> >> It doesn't let me download the manual but from the pictures it looks >> like you need to be closer than an inch. >> > > can't find any mention of distance it is probably a liability thing. > > don't the wires come out of the box so you can easily get close? >
It's all in metal conduit, into and out of the box, all the way to the pumps. Has to be. -- Regards, Joerg http://www.analogconsultants.com/
On 2016-04-18 15:53, legg wrote:
> On Sun, 17 Apr 2016 13:55:05 -0700, Joerg <news@analogconsultants.com> > wrote: > >> Folks, >> >> A system needs to be able to detect whether a pole transformer has >> failed and stopped feeding power to a pump. The transformer will be >> 100ft or more away. The detection has to work even without any power >> flow meaning we can only detect the presence of a 60Hz electric field >> that leaks from the various boxs such as a breaker box. >> >> In order not to get fooled by 60Hz from other overhead lines I was >> wondering if classic pole transformers generate enough 3rd and 5th >> harmonics to distinguish the field emanating from secondary wires from >> that coming from overhead HV lines. Does anyone know where to find info >> about that? > > You should be able to differentiate the ambient field from near-field > using two sensors, regardless of their content. >
Sure, but then we have the same situation as we would if sticking a 2nd sensor unit inside the panel next to a breaker with a radio repeater on the outside: The need to ship two units -> $$$. The goal is to have a single self-contained "sniffer box", no wires, nothing going in and out in terms of connections. -- Regards, Joerg http://www.analogconsultants.com/
On Tue, 19 Apr 2016 01:43:25 +1000, Joerg <news@analogconsultants.com>  
wrote:

> On 2016-04-18 08:32, John Larkin wrote: >> On Mon, 18 Apr 2016 07:41:45 -0700, Joerg <news@analogconsultants.com> >> wrote: >> >>> On 2016-04-17 15:02, John Larkin wrote: >>>> On Sun, 17 Apr 2016 14:14:36 -0700, Joerg <news@analogconsultants.com> >>>> wrote: >>>> >>>>> On 2016-04-17 14:00, John Larkin wrote: >>>>>> On Sun, 17 Apr 2016 13:55:05 -0700, Joerg >>>>>> <news@analogconsultants.com> >>>>>> wrote: >>>>>> >>>>>>> Folks, >>>>>>> >>>>>>> A system needs to be able to detect whether a pole transformer has >>>>>>> failed and stopped feeding power to a pump. The transformer will be >>>>>>> 100ft or more away. The detection has to work even without any >>>>>>> power >>>>>>> flow meaning we can only detect the presence of a 60Hz electric >>>>>>> field >>>>>>> that leaks from the various boxs such as a breaker box. >>>>>> >>>>>> If the transformer fails, won't that stop power to the pump? >>>>>> >>>>> >>>>> Yup. The system is a mote network that then needs to send out an >>>>> alarm. >>>>> The pumps aren't always running and the alert should not go out when >>>>> no >>>>> power is drawn but mains power is available. >>>>> >>>>> >>>>>>> >>>>>>> In order not to get fooled by 60Hz from other overhead lines I was >>>>>>> wondering if classic pole transformers generate enough 3rd and 5th >>>>>>> harmonics to distinguish the field emanating from secondary wires >>>>>>> from >>>>>>> that coming from overhead HV lines. Does anyone know where to find >>>>>>> info >>>>>>> about that? >>>>>> >>>>>> The way people often pick up an AC trigger for a scope or something >>>>>> is >>>>>> to wrap a couple of turns of insulated wire on top of the ac-high >>>>>> insulated wire, and drive a high-impedance amp. Can you get inside >>>>>> the >>>>>> breaker box, or access a motor wire, free-air or inside a conduit? >>>>>> >>>>> >>>>> That's exactly what we want to avoid. It's all outdoor stuff so even >>>>> running a non-connected sniffer wire into the breaker box is frowned >>>>> upon. >>>> >>>> Is the feed open-wire on a pole? >>>> >>> >>> I don't quite understand that question. It's the usual, two 10-12kV >>> wires string along on poles, a transformer, and a 240VAV two-phase drop >>> of 100ft down to the pumps. They like to keep that last pole with the >>> transformer away that far to minimise it being damaged by trucks, farm >>> equipment and such. >>> >>> >>>> Who's doing the frowning? >>>> >>> >>> The customer. They want a solution they can crack out of a package and >>> stick to the outside of the breaker box or somewhere around that. No >>> wiring. Doing anything inside a breaker box legally requires an >>> electrician to come out and that's not desired because of the high >>> cost. >> >> Outside of a metal breaker box, there's no h-field with no current, >> and no e-field leaking out. The ambient e-field will be dominated by >> other stuff, like other circuits and light bulbs in the room. >> > > There is no room. Just that last pole, the transformer, a meter and > breaker box and the pumps. Other than that maybe some cattle. > > We'd be counting on the ever so small leaking E-field because with the > pumps turned off that's all there is going to be. Hence my question > whether we could use harmonics to see a change versus the E-field coming > from the distant HV line. The engineer taking care of the software side > is very good at extracting signature signals to hear "the grass grow". > > >> Maybe it can't be done. >> > > Possible. That's why we are engineers, to try out until we are 110% sure > it truly can't be done. If it turns out it can be done the company has a > leg up on the competition, big time :-) > > >> Suppose you had a small, coin-sized magnetized thing. Would you need >> an electrician to open the breaker box, stick it to the cover or the >> side inside, and close it? You don't need an electrician to open the >> box and flip breakers. >> > > No, but many outdoor boxes have a gasket seal which you technically are > not allowed to compromise. What we were mulling is a 2nd transmitter > inside the box. But that would probably become a show-stopper. >
What about audio? The transformer and all the rest must produce some hum and when the transformer dies I bet it sound different.
On Monday, April 18, 2016 at 7:35:41 PM UTC-4, Joerg wrote:
> On 2016-04-18 14:56, Lasse Langwadt Christensen wrote: > > Den mandag den 18. april 2016 kl. 23.38.08 UTC+2 skrev Joerg: > >> On 2016-04-18 14:19, Lasse Langwadt Christensen wrote: > >>> Den s&#2013266168;ndag den 17. april 2016 kl. 22.54.36 UTC+2 skrev Joerg: > >>>> Folks, > >>>> > >>>> A system needs to be able to detect whether a pole transformer has > >>>> failed and stopped feeding power to a pump. The transformer will be > >>>> 100ft or more away. The detection has to work even without any power > >>>> flow meaning we can only detect the presence of a 60Hz electric field > >>>> that leaks from the various boxs such as a breaker box. > >>>> > >>>> In order not to get fooled by 60Hz from other overhead lines I was > >>>> wondering if classic pole transformers generate enough 3rd and 5th > >>>> harmonics to distinguish the field emanating from secondary wires from > >>>> that coming from overhead HV lines. Does anyone know where to find info > >>>> about that? > >>>> > >>>> -- > >>>> Regards, Joerg > >>>> > >>>> http://www.analogconsultants.com/ > >>> > >>> electrical-testers/fluke-2ac-electrical-tester.html > >>> > >> > >> http://en-us.fluke.com/products/electrical-testers/fluke-2ac-electrical-tester.html#resources > >> > >> It doesn't let me download the manual but from the pictures it looks > >> like you need to be closer than an inch. > >> > > > > can't find any mention of distance it is probably a liability thing. > > > > don't the wires come out of the box so you can easily get close? > > > > It's all in metal conduit, into and out of the box, all the way to the > pumps. Has to be. > > -- > Regards, Joerg > > http://www.analogconsultants.com/
OK... well now I see the problem. Can I stick probes into the surface of the conduit? Never mind the E-fields don't make it to the surface. You might see some E-fields on the surface.... (conduit dependent) some multi probe thing. Sounds like a science project. :^) George H.
On 2016-04-18 17:09, David Eather wrote:
> On Tue, 19 Apr 2016 01:43:25 +1000, Joerg <news@analogconsultants.com> > wrote: > >> On 2016-04-18 08:32, John Larkin wrote: >>> On Mon, 18 Apr 2016 07:41:45 -0700, Joerg <news@analogconsultants.com> >>> wrote: >>> >>>> On 2016-04-17 15:02, John Larkin wrote: >>>>> On Sun, 17 Apr 2016 14:14:36 -0700, Joerg <news@analogconsultants.com> >>>>> wrote: >>>>> >>>>>> On 2016-04-17 14:00, John Larkin wrote: >>>>>>> On Sun, 17 Apr 2016 13:55:05 -0700, Joerg >>>>>>> <news@analogconsultants.com> >>>>>>> wrote: >>>>>>> >>>>>>>> Folks, >>>>>>>> >>>>>>>> A system needs to be able to detect whether a pole transformer has >>>>>>>> failed and stopped feeding power to a pump. The transformer will be >>>>>>>> 100ft or more away. The detection has to work even without any >>>>>>>> power >>>>>>>> flow meaning we can only detect the presence of a 60Hz electric >>>>>>>> field >>>>>>>> that leaks from the various boxs such as a breaker box. >>>>>>> >>>>>>> If the transformer fails, won't that stop power to the pump? >>>>>>> >>>>>> >>>>>> Yup. The system is a mote network that then needs to send out an >>>>>> alarm. >>>>>> The pumps aren't always running and the alert should not go out >>>>>> when no >>>>>> power is drawn but mains power is available. >>>>>> >>>>>> >>>>>>>> >>>>>>>> In order not to get fooled by 60Hz from other overhead lines I was >>>>>>>> wondering if classic pole transformers generate enough 3rd and 5th >>>>>>>> harmonics to distinguish the field emanating from secondary >>>>>>>> wires from >>>>>>>> that coming from overhead HV lines. Does anyone know where to >>>>>>>> find info >>>>>>>> about that? >>>>>>> >>>>>>> The way people often pick up an AC trigger for a scope or >>>>>>> something is >>>>>>> to wrap a couple of turns of insulated wire on top of the ac-high >>>>>>> insulated wire, and drive a high-impedance amp. Can you get >>>>>>> inside the >>>>>>> breaker box, or access a motor wire, free-air or inside a conduit? >>>>>>> >>>>>> >>>>>> That's exactly what we want to avoid. It's all outdoor stuff so even >>>>>> running a non-connected sniffer wire into the breaker box is >>>>>> frowned upon. >>>>> >>>>> Is the feed open-wire on a pole? >>>>> >>>> >>>> I don't quite understand that question. It's the usual, two 10-12kV >>>> wires string along on poles, a transformer, and a 240VAV two-phase drop >>>> of 100ft down to the pumps. They like to keep that last pole with the >>>> transformer away that far to minimise it being damaged by trucks, farm >>>> equipment and such. >>>> >>>> >>>>> Who's doing the frowning? >>>>> >>>> >>>> The customer. They want a solution they can crack out of a package and >>>> stick to the outside of the breaker box or somewhere around that. No >>>> wiring. Doing anything inside a breaker box legally requires an >>>> electrician to come out and that's not desired because of the high >>>> cost. >>> >>> Outside of a metal breaker box, there's no h-field with no current, >>> and no e-field leaking out. The ambient e-field will be dominated by >>> other stuff, like other circuits and light bulbs in the room. >>> >> >> There is no room. Just that last pole, the transformer, a meter and >> breaker box and the pumps. Other than that maybe some cattle. >> >> We'd be counting on the ever so small leaking E-field because with the >> pumps turned off that's all there is going to be. Hence my question >> whether we could use harmonics to see a change versus the E-field >> coming from the distant HV line. The engineer taking care of the >> software side is very good at extracting signature signals to hear >> "the grass grow". >> >> >>> Maybe it can't be done. >>> >> >> Possible. That's why we are engineers, to try out until we are 110% >> sure it truly can't be done. If it turns out it can be done the >> company has a leg up on the competition, big time :-) >> >> >>> Suppose you had a small, coin-sized magnetized thing. Would you need >>> an electrician to open the breaker box, stick it to the cover or the >>> side inside, and close it? You don't need an electrician to open the >>> box and flip breakers. >>> >> >> No, but many outdoor boxes have a gasket seal which you technically >> are not allowed to compromise. What we were mulling is a 2nd >> transmitter inside the box. But that would probably become a >> show-stopper. >> > > What about audio? The transformer and all the rest must produce some hum > and when the transformer dies I bet it sound different.
It'll be very faint, the transformer is 100ft or more away (not an allowed site to install anything there) and there can be lots of other noise muffling such faint sounds. -- Regards, Joerg http://www.analogconsultants.com/
On Monday, April 18, 2016 at 4:38:12 PM UTC-7, Joerg wrote:

> The goal is to have a single self-contained "sniffer box", no wires, > nothing going in and out in terms of connections.
If nothing goes out, you never get any information, of course... which simplifies the 'sniffer' function, you just drop that requirement. If you can't standardize on a meter that has reporting, or wire a reporting relay inside a breaker box, or depend on a noisy or light-emitting or signal-flag-waving bit of driven apparatus, the power from that pole pig transformer is only a potential, not an action with consequences. I'm dubious that the potential alone, within "a metal enclosure", is something that can be reliably sensed from without.
On 2016-04-18 17:10, George Herold wrote:
> On Monday, April 18, 2016 at 7:35:41 PM UTC-4, Joerg wrote: >> On 2016-04-18 14:56, Lasse Langwadt Christensen wrote: >>> Den mandag den 18. april 2016 kl. 23.38.08 UTC+2 skrev Joerg: >>>> On 2016-04-18 14:19, Lasse Langwadt Christensen wrote: >>>>> Den s&#2013266168;ndag den 17. april 2016 kl. 22.54.36 UTC+2 skrev Joerg: >>>>>> Folks, >>>>>> >>>>>> A system needs to be able to detect whether a pole transformer has >>>>>> failed and stopped feeding power to a pump. The transformer will be >>>>>> 100ft or more away. The detection has to work even without any power >>>>>> flow meaning we can only detect the presence of a 60Hz electric field >>>>>> that leaks from the various boxs such as a breaker box. >>>>>> >>>>>> In order not to get fooled by 60Hz from other overhead lines I was >>>>>> wondering if classic pole transformers generate enough 3rd and 5th >>>>>> harmonics to distinguish the field emanating from secondary wires from >>>>>> that coming from overhead HV lines. Does anyone know where to find info >>>>>> about that? >>>>>> >>>>>> -- >>>>>> Regards, Joerg >>>>>> >>>>>> http://www.analogconsultants.com/ >>>>> >>>>> electrical-testers/fluke-2ac-electrical-tester.html >>>>> >>>> >>>> http://en-us.fluke.com/products/electrical-testers/fluke-2ac-electrical-tester.html#resources >>>> >>>> It doesn't let me download the manual but from the pictures it looks >>>> like you need to be closer than an inch. >>>> >>> >>> can't find any mention of distance it is probably a liability thing. >>> >>> don't the wires come out of the box so you can easily get close? >>> >> >> It's all in metal conduit, into and out of the box, all the way to the >> pumps. Has to be. >> >> -- >> Regards, Joerg >> >> http://www.analogconsultants.com/ > > OK... well now I see the problem. > Can I stick probes into the surface of the conduit? > Never mind the E-fields don't make it to the surface. >
We'll certainly try everywhere, not just at the breaker box.
> You might see some E-fields on the surface.... > (conduit dependent) > some multi probe thing. > Sounds like a science project. :^) >
It sure will be one and we are prepared for that. The problem will be to test the alert case. "Hey, you, would you mind climbing up that pole and opening the big fuse once more?" -- Regards, Joerg http://www.analogconsultants.com/
On Mon, 18 Apr 2016 16:29:11 -0700, Joerg <news@analogconsultants.com>
wrote:

>On 2016-04-18 14:58, George Herold wrote: >> On Monday, April 18, 2016 at 5:34:33 PM UTC-4, Joerg wrote: >>> On 2016-04-18 14:11, makolber@yahoo.com wrote: >>>> I don't understand the quesiton... >>>> >>>> seems you just want to know if the supply voltage is there, or not there? >>>> >>> >>> Yup, without contacting anything or breaching any enclosure. >>> >>> >>>> why all the stuff about harmonics? >>>> >>> >>> The idea was to sense an E-field but in order to distinguish the >>> transformer output E-field from older 60Hz fields rely on the harmonics >>> that naturally occur because there will be some core saturation. Not >>> sure if that difference is strong enough which is why I asked here. >> >> Joerg, (perhaps a stupid question.) >> But if there's no, or very little, current flowing why >> will there be much B-field? (and any saturation.) >> > >John was hinting that a meter might radiate enough magnetic energy. But >not sure if smart meters also would. > >
An all-electronic meter with an inner shield, which is common, wouldn't leak much e or h field. -- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
On Mon, 18 Apr 2016 16:31:39 -0700, Joerg <news@analogconsultants.com>
wrote:

>On 2016-04-18 14:50, whit3rd wrote: >> On Monday, April 18, 2016 at 8:02:21 AM UTC-7, Joerg wrote: >>> On 2016-04-18 07:48, Phil Hobbs wrote: >> >>>> I'd be wanting to move the goal posts and cycle the pump every few hours >>>> just to make sure. >> >>> We can't. It's all automatic and often legacy equipment that some might >>> even call pre-historic. >> >> Just for giggles: is there a meter on these drops? A smart meter, that takes >> 3W all the time, that has wireless reporting back to the utility? If you >> could read out the meter, it'd solve the problem instantly. >> > >Can't rely on that, we have to cover all situations. Many places will >still have analog meters, some may not have meters at all and instead >pay a flat rate. Or they are on a company/farm grid where there is no >need for metering.
Well, don't make it too easy on us. -- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com