ECN Forum Forums General Topics of the Trade Non-US Electrical Systems & Trades Unusual transformer

Now to some of the other points raised.

BJ,
Although it would be hard to find single-phase lines running for miles here, there are certainly quite a few short 2-wire spurs around the area. This part of Norfolk (county) consists mostly of small towns and villages, interspersed with open countryside (we're not talking anything like as open as Nebraska or Wyoming of course, but it has a fairly low density of population by English standards ).

The road I took this picture on runs about 5 miles across open fields, with just an odd house or pair of houses, church etc. dotted along the way.

Going back to the photos at the top of the thread, there is a 3-phase line running almost at right-angles across the road about 300 yards to the left from which this 2-w spur is tapped. The HV lines going off the picture to the right finish about another quarter-mile further on at a xfmr which feeds two or three houses, so this particular 1-ph spur is under a half-mile long. There are more similarly short spurs along the route feeding homes on this road and the tiny lanes off to the sides.

Trumpy,
It's a standard step-down xfmr to provide a 2-wire 240V domestic supply. The house is actually out of the shot on the opposite side of the road to the pole.

DJK,
These are standard 11kV lines which are used for local distribution throughout Britain. Power comes into this area on 33kV feeders, which is another standard distribution voltage here. (According to the local utility, there are still a few old 6600V networks in this region, but they are few and far between.)



[This message has been edited by pauluk (edited 03-19-2003).]

The numbers are interesting. Remember that WebSparky's 95-year-old transformer in Cleveland showing a 6,600/11,400V primary on its nameplate? With external bushings {connections} and jumpers, it could be served with 6.6kV with primary in delta and 11.4kV connected in wye. https://www.electrical-contractor.net/ubb/Forum4/HTML/000256.html

Paul,
In your last pic, you showed a Pole-Mounted Tank Transformer, what type of Fuses are they on the side of the pole, to the front of the pic?.
I take it that the Neutral is Earthed at the Xformer?.
What is the VA rating of one of these trannys?, just curious.

Would one of the following guesses possibly apply to the item shown in the first images?:

<OL TYPE=A>

[*]Autotransformer?,

[*]Circuit Breaker / Motorized Cut-out?,

[*]Voltage Boosting Transformer?,

[*]Series Street Lighting Regulating Transformer?,

[*]Power Factor Correcting Assemblige (Caps + Inductors)?,

[*]Space People Bringing Stuff To Earth?
</OL>

Anything sound possible?

Scott35

ESB in Ireland seems to have used the US style mountings generally. Mostly round. I'm sure they're prob. from various manufacturers though. More than likely Siemens, AEG or GE.

Have you ever seen the French distribution poles with switches accessable from the bottom of the pole to reset trips or something, not quite sure what they're used for but there's a large lever at the end of the pole.

Any ideas?

Tramway poles in Vienna have padlocked disconnect levers. I have never seen them on residential power poles though. Rural areas still have wooden poles, only HV distribution is on steel grid poles. Street lighting here in Vienna are waterproof flourescent battens with 2 tubes strung on wires between houses or on octagonal galvanized steel poles. At midnight one of the tubes is shut off. Other cities use wood or concrete lighting poles. (I think in the outskirts of Vienna they also have wooden poles, but these areas can hardly be considered to be within city limits, they look _very_ rural and even have 230/400V overhead distribution, something otherwise unknown in Vienna, downtown overhead services were removed in the early 20th century). Old overhead services were done with 4 individual wires, modern installations use quadruplex, like the US triplex OH, only with insulated neutral, but even in very rural areas they're starting to switch over to underground distribution.

In Ireland there is still plenty of overhead distribution in suburban areas that would date from the 1920's - early 1950's. Any suburbs / housing developments built after the early 1950s have underground cabling for power, phones and often cable television. The vast majority of our "closer" and nicer suburbs date from the 1920's and 30s though.

Typically you'd have 400V (380V) distribution on twisted or individual cables with a twisted pair going to each home usually to the highest point on the house i.e. the chimney top. Phone service runs in a similar configuration and cable television typically ran house-to-house at roof level.

The only thing that does make it different from most of Europe is that our suburbs are very "leafy" and tend to have large front gardens and lots of tree lined streets so most of the power lines and poles disappear, you don't really notice them. Many areas also had the services run behind the houses in lanes so there are no overhead lines on the streets.

The ESB uses a LOT of wood, all distribution lines are on wooden poles, even new installations. Much of the 110KV parts of the transmission network, including new parts are on very high wooden poles with modern pylon style insulators on the top. They're considered to look better and have less impact on the scenery than metal pylons. 220KV and 400KV lines are all on metal pylons.

Rural distribution is all on 10/20KV lines with pole mounted transformers feeding houses/farms individually. All wooden poles, very "US style".

The Cable TV networks are a little off topic but they deserve a mention.

They're generally much older than anything i've seen elsewhere. Cable hit surburban Dublin and Cork in the late 1960s and there were even small cable systems in the 1950s relaying BBC from large communal antennas that picked up broadcasts from the UK and fed them by cable when RTE was either non-exsistant or very very boring ! Many people in Dublin particuarly still call cable tv "Piped Television" or even "the relays".

When it was installed initially they just ran thick co-ax from a "head end" house to house under the facia boards just below roof level. The cable company would often give someone free cable if they'd agree to have a small amplifier fitted to boost the signal en-route. Those systems initially carried 2 Irish channels and 2/3 british channels and expanded as satellite became available and more channels went on air in the UK and IRL some even carried their own local programming. None of the channels were encrypted in Dublin and Cork adopted a US type set-top-box with analogue encryption. These boxes even came with wood paneling to match the TV sets of their era.

They've been re-wired with better co-ax to give more capacity in the 1980s and during the 1990s and 2000s they've been gradually converted to digital systems and fiber's been layed underground along streets, however the coax house-to-house network still carries all of the basic 18 to 30 channels that are available free to air and usually unencrypted, you just plug the cable into the TV (VHF band I/II/III and UHF)

I've seen a few places here where a disconnect has an operating rod and handle lower down the pole.

Underground distribution is certainly becoming more common here, and virtually all new housing estates seem to be built with all services underground now.

Even ignoring the latest projects, one really noticeable difference between an average American town and an average British town is in the amount of cabling one sees overhead. British towns seem to be lacking in overhead cables (or American towns seem to have a lot, depending upon your point of origin! ).

Scott35,
Good points you raise there (Don't think I'll vote for the last one though! ), but this appears to be just a regular distribution xfmr. It might not be completely visible in the photo, but the 11kV lines are just looped from one side of the pole to the other with the HV bushings on the xfmr connected straight across. The 240V lines leaving the pole below the HV and going off to the right are actually the service drop to a house on the opposite side of the road.

Trumpy,
Not sure of the actual rating of that xfmr above, but this one is 100kVa:

It has the same type fuses as above, but you can see them a little more clearly here;

They're a cartridge fuse, though I'm not sure of the rating.

By the way, for anyone who wasn't with us, these photos were originally posted this thread , along with some others of local distribution equipment.

On the wooden vs. metal poles argument, wood wins here on all the local 11 and 33kV lines. Metal lattice towers become the norm here for transmission at 132kV and above.

DJK,
Cable TV has a rather obscure history in the U.K. There were a few cable systems installed way back in the 1950s, mostly as communal antenna systems operating over very small areas (e.g. a single block) in towns which had poor reception. But they were rare, and generally only carried the regular free-to-air signals (which at the time meant one BBC channel and one ITA channel, with maybe BBC2 added when it started in the sixties).

It's really only in the last few years that cable TV has become more widespread, and still only in large cities. As such, the cabling has followed the modern trends, so cable TV line strung up as you see them in America, or as you describe in parts of Ireland just don't exist.

BJ,
Yes, I've been following the thread with the 95-year-old General Electric xfmr. Fascinating!

{Edited for moved images}


[This message has been edited by pauluk (edited 06-09-2003).]

Paul,

My eyes are terrible!!! Looked as if the Primary Feeder on the left side (furthest from person taking pictures) was connected as a "Common" to both the Transformer and the Secondary side!!!
I need to be more careful!!!

With that in mind, it's the oddest looking Pot I have ever seen! Strange how the HV Bushings are mounted on the Cylindrical portion of the enclosure - as opposed to mounting on the top.

Must be some advantages (arc quenching, birds being caught between phases, maybe wind stabilization / harmonic vibrations transfered to pole better???).
Must find out what's up!!!

Scott35

p.s. Would the Apparent Power rating of this Animal be around 25 KVA, or 37.5 KVA? Trying to "Scale" it to common Pot sizes in US pole mount distribution applications - falls in the 25-37.5 KVA range (as viewed by my great bionic eyes!)
Primary is 11 KV? (11,000 even, or 11,000 + some loose change ;-)...), and Secondary is 240 VAC?

Sure can find some odd Electrical Power equipment in the rural areas!

As to the Polyphase ones (the 3Ø 3Wire Transformers), have seen a bunch of those types around here! Bushings from the top and the fronts! Even remember seeing some of those fused cutouts here and there!

Scott35

I dpn't work on this side of power, so I'm not very good at eyeballing the rating of these xfmrs, and as has been mentioned in here before the variation in design parameters can make a visual "guess-timate" difficult anyway.

Yes, the primary is 11kV, secondary 240V. This xfmr is feeding one house, and residential services these days are usually 100A, so 25kVA or thereabouts would be reasonable.

I think I see what you mean about the primary/secondary cabling. It's complicated by the fact that this being a pole where each run is terminated and tensioned there are the jumpers across the pole. The jumper on one side of the primary line is supported by an insulator above the cross arm while the other jumper is run belowp it. From the angle of the picture, it could appear as though that jumper is heading toward one of the secondary lines.



[This message has been edited by pauluk (edited 03-21-2003).]