|
Other Vintage Household Electrical or Electromechanical Items For discussions about other vintage (over 25 years old) electrical and electromechanical household items. See the sticky thread for details. |
|
Thread Tools |
14th May 2018, 10:47 pm | #21 |
Dekatron
Join Date: Jul 2007
Location: Penrith, Cumbria, UK.
Posts: 3,687
|
Re: European voltage in the UK?
Is the east side different, then? Fed from elsewhere?
__________________
Regds, Russell W. B. G4YLI. |
15th May 2018, 8:26 am | #22 | |
Hexode
Join Date: Aug 2017
Location: Taunton, Somerset, UK.
Posts: 318
|
Re: European voltage in the UK?
Quote:
Remember also that EHV systems employ overhead line networks and that expensive distance protection is provided. These systems will invariably require fault impedance Voltage measurement. From a domestic viewpoint there are literally thousands of 6600V/433V nominal distribution transformers scattered around the UK. The majority of these units will have manually adjusted off load taps that are 2.5%, 5% & 7.5%. It follows that the Voltage could vary on a daily basis and that measurements at a socket may be different to ones next door neighbour. Note that automatic telephonically operated taps may have only recently been introduced as I worked on the original designs as late as 2005. Saying all that there are annoying issues in so far as tungsten filament lamps that used to be rated 250V. Following harmonisation they became 220V which meant a reduction in life coupled with a substantial increase in sales for the suppliers? |
|
15th May 2018, 12:23 pm | #23 |
Hexode
Join Date: Apr 2007
Location: Milton Keynes, Buckinghamshire, UK.
Posts: 329
|
Re: European voltage in the UK?
|
15th May 2018, 4:46 pm | #24 |
Pentode
Join Date: Oct 2017
Location: Newton-le-Willows, Merseyside, UK.
Posts: 158
|
Re: European voltage in the UK?
The whole harmonisation thing was a joke from start to finish, I have spoken to more than one senior power engineer on networks, and they all say the same,"never happen here". It is as others have said, not as easy as flicking a switch or two to alter the voltage, a lot of components on the network would need to be replaced.
Interestingly enough, I've plugged a logging meter in at home and seen the voltage shift from as high as 254, to as low as 220 over a 24 hour period. The funniest incident happened a few years back, I had issues with lights dimming etc and phoned the DNO, this young lad came out, tested the earth loop value and pronounced that all was well, from the results I had, clearly it wasn't. I attached my test meters and as I increased the load, you could see the voltage drop, I actually got it down to about 150V when pulling about 40 amps. He then said that it was a joint on the service cable that must have failed, and promptly began tearing up the pavement. Along came a more senior engineer and informed him that, if he'd read the mornings briefing notes, he'd have realised that the ring feeding our street had developed a fault, and we were actually currently on the end of a long radial, hence the volt drop. After a telling off from his boss, he left, a much wiser bloke, I bet he never failed to read the briefing notes after that. |
15th May 2018, 4:53 pm | #25 |
Dekatron
Join Date: Apr 2012
Location: Worksop, Nottinghamshire, UK.
Posts: 5,554
|
Re: European voltage in the UK?
We are on the end of a radial being mid terrace.
When we get dim lights and flickering there is usually smoke and sparks from the overhead cable. The fault report just goes "sparks have been seen there". They just fix it quickly. |
15th May 2018, 5:53 pm | #26 | |
Dekatron
Join Date: May 2010
Location: Greater Manchester, UK.
Posts: 18,725
|
Re: European voltage in the UK?
Quote:
https://www.***********/gp/g3zvt/7QRTSQ That was 6 months ago Since the LV back-feed began our voltage has reduced from 245 to about 237. We are still waiting for the new substation, the excavation has been back-filled and tarmacked to a high standard. I was amazed that the reconfiguration could be done remotely without local intervention.
__________________
-- Graham. G3ZVT |
|
15th May 2018, 6:26 pm | #27 |
Hexode
Join Date: Aug 2017
Location: Taunton, Somerset, UK.
Posts: 318
|
Re: European voltage in the UK?
The vast majority of transformers in our distribution substations will be configured such that 2 transformers will be provided but that each transformer will have the capacity to supply the total needs of that particular substation.
The secondary of each transformer will feed a switchboard that will comprise of two incoming circuit breakers that supplies power to a common busbar connected within the switchboard. Centrally located within the switchboard is a further circuit breaker which connects each half of the busbars if so requested; it is called a bus section breaker or bus tie as referred to in ANSI nomenclature. There will be outgoing circuit breakers on each half of the busbar that will feed one end of the ring (loop) circuit referred to by other. In this configuration each transformer will run at 50% if the substation is running at maximum capacity. The latter system is employed on a global basis as it has the effect of increasing significantly the life of the transformers. In the event there is a fault on either transformer or similar all one need do is close the bus section breaker which will parallel the two transformers and this doubles the capacity of the substation. The only drawback is that the fault level will increase by 100%. All of the breakers are controlled remotely by the DNO by way of their DCS (Distributed Control System) and higher level SCADA (Supervisory Control and Data Acquisition System) using dedicated or BT telecontrol networks. |
15th May 2018, 8:09 pm | #28 | |
Dekatron
Join Date: Jul 2007
Location: Penrith, Cumbria, UK.
Posts: 3,687
|
Re: European voltage in the UK?
Quote:
Interesting about calling the Bus-Section Switch a Bus-Tie. Never heard that one before!
__________________
Regds, Russell W. B. G4YLI. |
|
15th May 2018, 8:38 pm | #29 |
Dekatron
Join Date: May 2010
Location: Greater Manchester, UK.
Posts: 18,725
|
Re: European voltage in the UK?
Here is the top of the non functioning transformer
And here is the other cabinet, presumably containing the switchgear. I have never had the opportunity to see inside this cabinet, but should I expect to see some modern comms equipment in there? Is the signalling carried over the HV cable? Is this type of installation common, I don't think I have seen anything quite like it anywhere else.
__________________
-- Graham. G3ZVT |
15th May 2018, 9:28 pm | #30 |
Octode
Join Date: Feb 2009
Location: Bletchley, Buckinghamshire, UK.
Posts: 1,223
|
Re: European voltage in the UK?
|
15th May 2018, 10:21 pm | #31 |
Hexode
Join Date: Jan 2012
Location: Weymouth, Dorset, UK.
Posts: 422
|
Re: European voltage in the UK?
Bookman do you mean the 33/11Kv substations? I ask because ive only with one exception seen local11/0.4 Kv substations with a single transformer the only double tranny arrangment ive seen was in the centre of town and I think that was an odd system feeding into old DC cables
|
16th May 2018, 5:25 am | #32 |
Nonode
Join Date: Jan 2010
Location: North Somerset, UK.
Posts: 2,130
|
Re: European voltage in the UK?
IME, most low voltage substations contain only a single transformer. Protection against failure is usually be feeding from adjacent parts of the network.
Small transformers for isolated groups of consumers or for a single consumer have no such facility. Transformer failures are handled by either quick replacement, or by use of a generator. Duplicated LV transformers are generally due to either exceptional load growth, or as above, legacy cable systems intended for 3 wire DC and now supplied with 6 phase AC. High voltage substations do indeed often have duplicate transformers so as to ensure continuity of supply in case of a failure. |
16th May 2018, 7:16 am | #33 | |
Hexode
Join Date: Aug 2017
Location: Taunton, Somerset, UK.
Posts: 318
|
Re: European voltage in the UK?
Quote:
Don't forget that these are distribution items and as such there is a common communication link in so far as someone would soon telephone somebody if the power was off. |
|
16th May 2018, 4:45 pm | #34 | |
Hexode
Join Date: Jan 2012
Location: Weymouth, Dorset, UK.
Posts: 422
|
Re: European voltage in the UK?
Quote:
|
|
16th May 2018, 6:28 pm | #35 |
Dekatron
Join Date: Jul 2007
Location: Penrith, Cumbria, UK.
Posts: 3,687
|
Re: European voltage in the UK?
Or as part of a commissioned contract that requires belt-and-braces avoidance of single point-of-failure: industry, broadcasting, MoD... Can be configured as both on load-sharing (depending on fault capacity of the board) or 'either/or' with planned changeover intervals for maintenance.
__________________
Regds, Russell W. B. G4YLI. |
16th May 2018, 7:02 pm | #36 | |
Dekatron
Join Date: Apr 2012
Location: Wiltshire, UK.
Posts: 14,010
|
Re: European voltage in the UK?
Quote:
My "230V" supply generally sits at around 235V as seen on one presentation-phase. |
|
17th May 2018, 9:10 am | #37 |
Hexode
Join Date: Aug 2017
Location: Taunton, Somerset, UK.
Posts: 318
|
Re: European voltage in the UK?
Your situation poses a further interesting question in so far as Voltage amplitudes and its control. In this it is not particularly a problem for LV single phase applications. It's more the three phase issues for your type of load; in particular any 3 ph machines associated with farming machinery. Here I am referring to how torque is directly proportional to Voltage Squared?
|
17th May 2018, 4:05 pm | #38 | |
Pentode
Join Date: Oct 2017
Location: Newton-le-Willows, Merseyside, UK.
Posts: 158
|
Re: European voltage in the UK?
Quote:
Served him right, he had this idea that because he owned the sub, he had some kind of right to be connected to the grid, he was wrong! |
|
17th May 2018, 4:08 pm | #39 |
Pentode
Join Date: Oct 2017
Location: Newton-le-Willows, Merseyside, UK.
Posts: 158
|
Re: European voltage in the UK?
here's a link to the network design manual, some of you may find it interesting, it shows how things are done and how loads are calculated, there's one or two surprises in there for people who don't work in our industry. enjoy
https://www.***********/document/337...gn-Manual-v7-7 |
17th May 2018, 6:12 pm | #40 |
Dekatron
Join Date: May 2010
Location: Greater Manchester, UK.
Posts: 18,725
|
Re: European voltage in the UK?
__________________
-- Graham. G3ZVT Last edited by Graham G3ZVT; 17th May 2018 at 6:17 pm. Reason: forum software will not handle the link. TinyURL alternative used. |