Forums

Harmonics in pole power transformers?

Started by Joerg April 17, 2016
On Mon, 18 Apr 2016 07:58:30 -0700, Joerg <news@analogconsultants.com>
wrote:

>On 2016-04-18 07:57, legg wrote: >> On Sun, 17 Apr 2016 17:16:12 -0700 (PDT), George Herold >> <gherold@teachspin.com> wrote: >> >>> On Sunday, April 17, 2016 at 4:54:36 PM UTC-4, Joerg 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? >>>> >>>> -- >>>> Regards, Joerg >>>> >>>> http://www.analogconsultants.com/ >>> >>> Magneto-striction causes the transformer to vibrate at 120 Hz, >>> I don't know if you could sense that. >>> > >Audio buzz isn't reliable here because the transformer will be far away. >All we have is any E-field leaking out from conduit and the breaker box. >The good thing is, we can be right at the breaker box, just not in it. > > >>> George H. >> >> Transformers can fail and still buzz. >> >> There are many reasons why a pump might fail. Expending effort at >> sensing just a single one of these is misdirected. >> > >No, it is not. The fact that transformer or HV line failure is by far >the highest concern in this application is based on clear statistical >evidence. >
I'd like to see THOSE statistics. You're trying to see if a pump is functional, when it's not supposed to be running. Does this make sense to you? You might check the product of the pump's operation, to get evidence of recent function: traces of pumped media present where it's supposed to be, not present where it ain't. RL RL
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. RL
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? -Lasse
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.) I guess I was thinking about trying to shield the rest of the world from the measurement. (No loops, star ground, or 60 Hz magnetic fields may find a path in.) George H.
> > -- > Regards, Joerg > > http://www.analogconsultants.com/
Den mandag den 18. april 2016 kl. 23.50.56 UTC+2 skrev legg:
> On Mon, 18 Apr 2016 07:58:30 -0700, Joerg <news@analogconsultants.com> > wrote: > > >On 2016-04-18 07:57, legg wrote: > >> On Sun, 17 Apr 2016 17:16:12 -0700 (PDT), George Herold > >> <gherold@teachspin.com> wrote: > >> > >>> On Sunday, April 17, 2016 at 4:54:36 PM UTC-4, Joerg 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? > >>>> > >>>> -- > >>>> Regards, Joerg > >>>> > >>>> http://www.analogconsultants.com/ > >>> > >>> Magneto-striction causes the transformer to vibrate at 120 Hz, > >>> I don't know if you could sense that. > >>> > > > >Audio buzz isn't reliable here because the transformer will be far away. > >All we have is any E-field leaking out from conduit and the breaker box. > >The good thing is, we can be right at the breaker box, just not in it. > > > > > >>> George H. > >> > >> Transformers can fail and still buzz. > >> > >> There are many reasons why a pump might fail. Expending effort at > >> sensing just a single one of these is misdirected. > >> > > > >No, it is not. The fact that transformer or HV line failure is by far > >the highest concern in this application is based on clear statistical > >evidence. > > > I'd like to see THOSE statistics. > > You're trying to see if a pump is functional, when it's not supposed > to be running. Does this make sense to you?
if it is, say, a pump to keep a basement from flooding or some cows from going thirsty it makes perfect sense to get an electrician out to fix the power before it is needed -Lasse
On Mon, 18 Apr 2016 14:35:05 -0700, Joerg <news@analogconsultants.com>
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.
Distribution transformers are very efficient, to save energy. I'd expect they don't run much into saturation. The AC line sinewave around here is flat-topped, but probably from non-PFC electronic loads. https://dl.dropboxusercontent.com/u/53724080/SF/AC_Line.JPG If I was a motor, I might not know which way to turn. -- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
On Monday, 18 April 2016 21:48:05 UTC+1, Lasse Langwadt Christensen  wrote:

> don't many of the electronic ones have an IR interface so you can just ask > it if it is on?
Many of the electronic ones also have a red LED which flashes briefly every time a certain amount of energy has been delivered. So long as there is a small load present all the time the flashing will indicate that power is available. John
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.
> I guess I was thinking about trying to shield the rest of the > world from the measurement. (No loops, star ground, or 60 Hz > magnetic fields may find a path in.) >
We probably need E-field here. -- Regards, Joerg http://www.analogconsultants.com/
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. -- Regards, Joerg http://www.analogconsultants.com/
On 2016-04-18 15:02, Lasse Langwadt Christensen wrote:
> Den mandag den 18. april 2016 kl. 23.50.56 UTC+2 skrev legg: >> On Mon, 18 Apr 2016 07:58:30 -0700, Joerg <news@analogconsultants.com> >> wrote: >> >>> On 2016-04-18 07:57, legg wrote: >>>> On Sun, 17 Apr 2016 17:16:12 -0700 (PDT), George Herold >>>> <gherold@teachspin.com> wrote: >>>> >>>>> On Sunday, April 17, 2016 at 4:54:36 PM UTC-4, Joerg 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? >>>>>> >>>>>> -- >>>>>> Regards, Joerg >>>>>> >>>>>> http://www.analogconsultants.com/ >>>>> >>>>> Magneto-striction causes the transformer to vibrate at 120 Hz, >>>>> I don't know if you could sense that. >>>>> >>> >>> Audio buzz isn't reliable here because the transformer will be far away. >>> All we have is any E-field leaking out from conduit and the breaker box. >>> The good thing is, we can be right at the breaker box, just not in it. >>> >>> >>>>> George H. >>>> >>>> Transformers can fail and still buzz. >>>> >>>> There are many reasons why a pump might fail. Expending effort at >>>> sensing just a single one of these is misdirected. >>>> >>> >>> No, it is not. The fact that transformer or HV line failure is by far >>> the highest concern in this application is based on clear statistical >>> evidence. >>> >> I'd like to see THOSE statistics. >> >> You're trying to see if a pump is functional, when it's not supposed >> to be running. Does this make sense to you? > > if it is, say, a pump to keep a basement from flooding or some cows from > going thirsty it makes perfect sense to get an electrician out to fix the > power before it is needed >
Bingo! -- Regards, Joerg http://www.analogconsultants.com/