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Harmonics in pole power transformers?

Started by Joerg April 17, 2016
On 2016-04-22 18:53, legg wrote:
> On Tue, 19 Apr 2016 12:29:26 -0400, Phil Hobbs > <pcdhSpamMeSenseless@electrooptical.net> wrote: > >> On 04/19/2016 12:19 PM, Cydrome Leader wrote: >>> Joerg <news@analogconsultants.com> wrote: >>>> 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! >>> >>> No. It costs too much to hire electricians. The problem will have to fix >>> itself. >>> >>> >> If you're the farmer or building owner, it's reasonable. On the other >> hand, if you're selling gizmos that will on average save several hundred >> dollars' worth of wasted time every few years, you can charge more for >> your gizmo. >> >> Everybody wins. What's not to like? >> >> Cheers >> >> Phil Hobbs > > Sounds more like low-labor corporate or absentee owner situation. > If it involved livestock, or even just irrigation, you'd need more > operating info than just the power being present at a pump. >
As I've said, such information is already being furnished. This whole topic is about furnishing an additional bit of information, mains power failure. Without needing an electrician to come out for the install.
> You could sell it to somebody at the corporate level - it doesn't have > to make sense, if you convince them it will 'on average save......'. >
It's not about big corp products either. -- Regards, Joerg http://www.analogconsultants.com/
On Sat, 23 Apr 2016 09:46:52 -0700, Joerg <news@analogconsultants.com>
wrote:

>On 2016-04-22 15:21, Jon Elson wrote: >> Joerg wrote: >> >> >>> SWER? That's only used in the more remote places of Australia and NZ. >>> Not here. It's always two-phase or three-phase via wires. >>> >> As far as I know, they don't use HV hot-hot much for residential. Most of >> the transformers have one HV terminal, and the housing is the ground return >> for the HV. I have seen in a FEW places transformers that had 2 HV >> terminals. These might have been on the truck for use in open delta setups, >> and that is all they had when they needed one for a repair. >> >> Our whole neighborhood is all single phase feed, one hot HV wire with a big >> insulator, and then a ground. The main street has 7200 V and 45 KV 3-phase. >> The 45 KV feeds a substaion a mile or so away. >> > >Weird. I walk our dogs every morning here in Cameron Park (California) >so today I double-checked: All transformers have two HV terminals. Most >of my walking route is along streets that have three HV phases along the >poles and the transformers are connected "round-robin" style to equalize >the load, each between two phases. Then there are small HV tap offs to >some clusters of homes with only two phases. But same transformers with >two HV prongs. > >Larger businesses have 3-phase transformers with three HV terminals. > >Our utility is PG&E. Running a fourth wire for neutral somehow doesn't >make sense from a cost POV. So they don't.
Neutrals are only developed at the final LV (<630V) stage. RL
On 2016-04-23 20:01, legg wrote:
> On Sat, 23 Apr 2016 09:46:52 -0700, Joerg <news@analogconsultants.com> > wrote: > >> On 2016-04-22 15:21, Jon Elson wrote: >>> Joerg wrote: >>> >>> >>>> SWER? That's only used in the more remote places of Australia and NZ. >>>> Not here. It's always two-phase or three-phase via wires. >>>> >>> As far as I know, they don't use HV hot-hot much for residential. Most of >>> the transformers have one HV terminal, and the housing is the ground return >>> for the HV. I have seen in a FEW places transformers that had 2 HV >>> terminals. These might have been on the truck for use in open delta setups, >>> and that is all they had when they needed one for a repair. >>> >>> Our whole neighborhood is all single phase feed, one hot HV wire with a big >>> insulator, and then a ground. The main street has 7200 V and 45 KV 3-phase. >>> The 45 KV feeds a substaion a mile or so away. >>> >> >> Weird. I walk our dogs every morning here in Cameron Park (California) >> so today I double-checked: All transformers have two HV terminals. Most >> of my walking route is along streets that have three HV phases along the >> poles and the transformers are connected "round-robin" style to equalize >> the load, each between two phases. Then there are small HV tap offs to >> some clusters of homes with only two phases. But same transformers with >> two HV prongs. >> >> Larger businesses have 3-phase transformers with three HV terminals. >> >> Our utility is PG&E. Running a fourth wire for neutral somehow doesn't >> make sense from a cost POV. So they don't. > > Neutrals are only developed at the final LV (<630V) stage. >
Jon was talking about the HV side, transformers with just one HV terminal. There you either need an extra HV neutral or SWER. -- Regards, Joerg http://www.analogconsultants.com/
On Sun, 24 Apr 2016 07:05:32 -0700, Joerg <news@analogconsultants.com>
wrote:

>On 2016-04-23 20:01, legg wrote: >> On Sat, 23 Apr 2016 09:46:52 -0700, Joerg <news@analogconsultants.com> >> wrote: >> >>> On 2016-04-22 15:21, Jon Elson wrote: >>>> Joerg wrote: >>>> >>>> >>>>> SWER? That's only used in the more remote places of Australia and NZ. >>>>> Not here. It's always two-phase or three-phase via wires. >>>>> >>>> As far as I know, they don't use HV hot-hot much for residential. Most of >>>> the transformers have one HV terminal, and the housing is the ground return >>>> for the HV. I have seen in a FEW places transformers that had 2 HV >>>> terminals. These might have been on the truck for use in open delta setups, >>>> and that is all they had when they needed one for a repair. >>>> >>>> Our whole neighborhood is all single phase feed, one hot HV wire with a big >>>> insulator, and then a ground. The main street has 7200 V and 45 KV 3-phase. >>>> The 45 KV feeds a substaion a mile or so away. >>>> >>> >>> Weird. I walk our dogs every morning here in Cameron Park (California) >>> so today I double-checked: All transformers have two HV terminals. Most >>> of my walking route is along streets that have three HV phases along the >>> poles and the transformers are connected "round-robin" style to equalize >>> the load, each between two phases. Then there are small HV tap offs to >>> some clusters of homes with only two phases. But same transformers with >>> two HV prongs. >>> >>> Larger businesses have 3-phase transformers with three HV terminals. >>> >>> Our utility is PG&E. Running a fourth wire for neutral somehow doesn't >>> make sense from a cost POV. So they don't. >> >> Neutrals are only developed at the final LV (<630V) stage. >> > > >Jon was talking about the HV side, transformers with just one HV >terminal. There you either need an extra HV neutral or SWER.
...and you weren't. RL
On 2016-04-24 08:15, legg wrote:
> On Sun, 24 Apr 2016 07:05:32 -0700, Joerg <news@analogconsultants.com> > wrote: > >> On 2016-04-23 20:01, legg wrote: >>> On Sat, 23 Apr 2016 09:46:52 -0700, Joerg <news@analogconsultants.com> >>> wrote: >>> >>>> On 2016-04-22 15:21, Jon Elson wrote: >>>>> Joerg wrote: >>>>> >>>>> >>>>>> SWER? That's only used in the more remote places of Australia and NZ. >>>>>> Not here. It's always two-phase or three-phase via wires. >>>>>> >>>>> As far as I know, they don't use HV hot-hot much for residential. Most of >>>>> the transformers have one HV terminal, and the housing is the ground return >>>>> for the HV. I have seen in a FEW places transformers that had 2 HV >>>>> terminals. These might have been on the truck for use in open delta setups, >>>>> and that is all they had when they needed one for a repair. >>>>> >>>>> Our whole neighborhood is all single phase feed, one hot HV wire with a big >>>>> insulator, and then a ground. The main street has 7200 V and 45 KV 3-phase. >>>>> The 45 KV feeds a substaion a mile or so away. >>>>> >>>> >>>> Weird. I walk our dogs every morning here in Cameron Park (California) >>>> so today I double-checked: All transformers have two HV terminals. Most >>>> of my walking route is along streets that have three HV phases along the >>>> poles and the transformers are connected "round-robin" style to equalize >>>> the load, each between two phases. Then there are small HV tap offs to >>>> some clusters of homes with only two phases. But same transformers with >>>> two HV prongs. >>>> >>>> Larger businesses have 3-phase transformers with three HV terminals. >>>> >>>> Our utility is PG&E. Running a fourth wire for neutral somehow doesn't >>>> make sense from a cost POV. So they don't. >>> >>> Neutrals are only developed at the final LV (<630V) stage. >>> >> >> >> Jon was talking about the HV side, transformers with just one HV >> terminal. There you either need an extra HV neutral or SWER. > > ...and you weren't. >
Sure I was. -- Regards, Joerg http://www.analogconsultants.com/
Joerg - have you had any luck finding harmonics charactoristic of power 
line transformers?

Hul

Joerg <news@analogconsultants.com> wrote:
> On 2016-04-23 20:01, legg wrote: > > On Sat, 23 Apr 2016 09:46:52 -0700, Joerg <news@analogconsultants.com> > > wrote: > > > >> On 2016-04-22 15:21, Jon Elson wrote: > >>> Joerg wrote: > >>> > >>> > >>>> SWER? That's only used in the more remote places of Australia and NZ. > >>>> Not here. It's always two-phase or three-phase via wires. > >>>> > >>> As far as I know, they don't use HV hot-hot much for residential. Most of > >>> the transformers have one HV terminal, and the housing is the ground return > >>> for the HV. I have seen in a FEW places transformers that had 2 HV > >>> terminals. These might have been on the truck for use in open delta setups, > >>> and that is all they had when they needed one for a repair. > >>> > >>> Our whole neighborhood is all single phase feed, one hot HV wire with a big > >>> insulator, and then a ground. The main street has 7200 V and 45 KV 3-phase. > >>> The 45 KV feeds a substaion a mile or so away. > >>> > >> > >> Weird. I walk our dogs every morning here in Cameron Park (California) > >> so today I double-checked: All transformers have two HV terminals. Most > >> of my walking route is along streets that have three HV phases along the > >> poles and the transformers are connected "round-robin" style to equalize > >> the load, each between two phases. Then there are small HV tap offs to > >> some clusters of homes with only two phases. But same transformers with > >> two HV prongs. > >> > >> Larger businesses have 3-phase transformers with three HV terminals. > >> > >> Our utility is PG&E. Running a fourth wire for neutral somehow doesn't > >> make sense from a cost POV. So they don't. > > > > Neutrals are only developed at the final LV (<630V) stage. > >
> Jon was talking about the HV side, transformers with just one HV > terminal. There you either need an extra HV neutral or SWER.
> -- > Regards, Joerg
> http://www.analogconsultants.com/
Joerg <news@analogconsultants.com> wrote:
> On 2016-04-22 15:21, Jon Elson wrote: >> Joerg wrote: >> >> >>> SWER? That's only used in the more remote places of Australia and NZ. >>> Not here. It's always two-phase or three-phase via wires. >>> >> As far as I know, they don't use HV hot-hot much for residential. Most of >> the transformers have one HV terminal, and the housing is the ground return >> for the HV. I have seen in a FEW places transformers that had 2 HV >> terminals. These might have been on the truck for use in open delta setups, >> and that is all they had when they needed one for a repair. >> >> Our whole neighborhood is all single phase feed, one hot HV wire with a big >> insulator, and then a ground. The main street has 7200 V and 45 KV 3-phase. >> The 45 KV feeds a substaion a mile or so away. >> > > Weird. I walk our dogs every morning here in Cameron Park (California) > so today I double-checked: All transformers have two HV terminals. Most > of my walking route is along streets that have three HV phases along the > poles and the transformers are connected "round-robin" style to equalize > the load, each between two phases. Then there are small HV tap offs to > some clusters of homes with only two phases. But same transformers with > two HV prongs. > > Larger businesses have 3-phase transformers with three HV terminals. > > Our utility is PG&E. Running a fourth wire for neutral somehow doesn't > make sense from a cost POV. So they don't.
PG&E may connect their distribution transformers phase to phase, but I assure you that many others connect them phase to ground.
On 2016-04-24 14:21, Hul Tytus wrote:
> Joerg - have you had any luck finding harmonics charactoristic of power > line transformers? >
No, we'll just be going after 60Hz for now but the system will be adaptable to doing 60Hz and 180Hz, allowing our own experiments. [...] -- Regards, Joerg http://www.analogconsultants.com/
On 2016-04-25 07:23, Ralph Barone wrote:
> Joerg <news@analogconsultants.com> wrote: >> On 2016-04-22 15:21, Jon Elson wrote: >>> Joerg wrote: >>> >>> >>>> SWER? That's only used in the more remote places of Australia and NZ. >>>> Not here. It's always two-phase or three-phase via wires. >>>> >>> As far as I know, they don't use HV hot-hot much for residential. Most of >>> the transformers have one HV terminal, and the housing is the ground return >>> for the HV. I have seen in a FEW places transformers that had 2 HV >>> terminals. These might have been on the truck for use in open delta setups, >>> and that is all they had when they needed one for a repair. >>> >>> Our whole neighborhood is all single phase feed, one hot HV wire with a big >>> insulator, and then a ground. The main street has 7200 V and 45 KV 3-phase. >>> The 45 KV feeds a substaion a mile or so away. >>> >> >> Weird. I walk our dogs every morning here in Cameron Park (California) >> so today I double-checked: All transformers have two HV terminals. Most >> of my walking route is along streets that have three HV phases along the >> poles and the transformers are connected "round-robin" style to equalize >> the load, each between two phases. Then there are small HV tap offs to >> some clusters of homes with only two phases. But same transformers with >> two HV prongs. >> >> Larger businesses have 3-phase transformers with three HV terminals. >> >> Our utility is PG&E. Running a fourth wire for neutral somehow doesn't >> make sense from a cost POV. So they don't. > > PG&E may connect their distribution transformers phase to phase, but I > assure you that many others connect them phase to ground. >
Can't remember having see those. The ones I know look like this, even in Europe: https://en.wikipedia.org/wiki/Distribution_transformer#/media/File:240v_transformer_-_geograph.org.uk_-_1062014.jpg -- Regards, Joerg http://www.analogconsultants.com/