HV & LV Electricity Metering in the UK

Hi


I have a customer who has an 11KV feed to there site and the Local Electricity Supply Company meters are on the HV side.

The Local Electricity Supply Company are trying to BuyBack the Transformers on the site (11Kv-415/690ac (quite a few of these)) and put in LV Metering...........

What benefits / disadvantages are there here ?

As i think the Local Electricity Supply Company may be trying to pull a fast one!

I can only speak for this side of the pond.

I doubt that the utility is pulling a fast one - they are pretty closely regulated. They certainly operate with their own best interest in mind, but in general they are less cutthroat than many industries.

If you are metered on the primary side you genearlly pay a lower rate, but purchase and maintanence of the transformers and switchgear is your problem. Being metered on the secondary side means lower maintenance, the utility pays for the transformers, but you pay a higher rate.

Have you simply asked the utility why they are making this proposal? Not everyone is a crook, you know.

Tom Jenkins said:

Have you simply asked the utility why they are making this proposal? Not everyone is a crook, you know.

Click to expand...

I gathered that the HV is cheaper than the LV,

The Utility when asked stated

"The Transformers when Bought back would show on the local electric boards assets and help their finances"!!!

They have failed to answer questions on Cost per Kva etc as yet! and were very sheepish when asked!

The Utility has also quoted to upgrade the comapanys supply as proposed new machines will exceed there demand, the proposed new HV will need to be trenched in a public highway about 3/4 mile (max) and the utility have quoted £500K.... but said it would be cheaper if they "bought" back the sites transformers

I'm not a EE, so just taking a guess. But if you measure on the LV side, can you then add in a "power factor" surcharge? Our local supplier has a surcharge if you power factor exceeds certain limits.

If your electricity supply company is anything like ComEd here in
in Chicago, you can't trust anything they tell you. No they are not crooks, but boy are they screwed up. ComEd's metering equipment has been known to be unreliable or outright screwed up. By doing your own monitoring you will learn a thing or two about being overcharged. You will need to argue with them hard and long to get your refund but they will give in if you have a proof.
I have seen refunds amounting to hundreds of thousands.
Any Company that is running a large electric biil and does not dilligently monitor ComEd's metering equipment is making a big mistake !
I doubt that your UK electricity supplier is any different.
Big government or public Company with near monopoly and union
workers. You thing that anybody gives a damn about keeping those meters in working condition? Keep dreaming!

I am on the Seatle City Light citizen rate advisory committee. Seattl Light is a public owned utility so things are a little different for them. One interesting thing is the State Public Utilities does not review their rate increases as they do with invester owned utilities ie Puget Sound Energy.

Electric utilities are a complicated and very interesting operatation. They have their own criteria which at first seem very puzzling and not cost effective at first look thru but when explained make sense.

Meterering for any parameter voltage current 15 minute demand (demand factor) power factor can be done on either side of the transformer.

Here in the US and certainly for City Light there meters are governed by both city ordinance and stater ordinance for accuracy just like the gas pumps or scales in a grocery store - yes they are inspected - and oh oh oh the miseries if you are caught intentionally cheating.

TRIVIA question
I wondered about this for years and finally got one of the meter guys at City Light to explain it to me - a year ago I did not know.

On the average household 240 Volt 3 wire Edison meter how do they get the time value in the readout of Kw Hr? The meter measures only current and voltage and DOES NOT have a clock. Yet they do (and accurately) get the hours in there somehow.

Dan Bentler

60 hertz, pretty accurate timepiece.

Someone mentioned that the UK was likely to be as unreliable as ComEd , generally the answer is no - all supplies are governed by The Electrical Light Act 1898-1908 , yes sure , mistakes do happen , and proving them might be a problem and of course it can go both ways , with a mistake in the customers favour , but there are statutory time limits for back claims etc

Unregistered said:

60 hertz, pretty accurate timepiece.

Click to expand...

Many years ago in Peoria (IL), we had a freq meter / strip recorder on the local utility. Amazing the variances that you would see. On Sunday mornings (like 3:00am) they would adjust for the week, so clocks would be right, more or less starting Monday morning. Many times, freq dropped as low as 38 cycles, to get the "avarage" in there.

Caterpillar went to National Bureau of Standards (WWV, etc) receivers to sync their clocks, due to the problems.

In some cases, CAT was making their own power, but that was due to natural gas was dirt cheap when they built some of their facilities.

Strip Recorders, a lot like lie detectors...

regards.....casey

I would suspect that buying HV in bulk will be cheaper than buying LV after the transformer. This is the case in much of the world.

Pursue the cost aspect HV vs LV vs power factor and make sure they are not going to charge you more for the LV. THEY PROBABLY ARE.

In some cases, CAT was making their own power, but that was due to natural gas was dirt cheap when they built some of their facilities.

Click to expand...

Actualy there is a clear trend in USA to build more and more cogen systems. Companies are doing this not to save money but to gain independence from the local utility Company. Articles on this subject appeared at various publications.

Someone mentioned that the UK was likely to be as unreliable as ComEd , generally the answer is no - all supplies are governed by The Electrical Light Act 1898-1908 ,

Click to expand...

Make sure you keep this electrical light act in place. Looking back at what happened in California few yars ago you know that deregulation of electrical utilities is not the way to go.

There are many things to consider,I was called to a plant in Mobile,Al in 2000 that was being built.A sparky from australia had been there when the power was applied for.He oppted for the 115Kv feed and bought the transformers,What he did'nt take in to thought was that in Al. If you let the power company istall the transformers you could cross the road with the power well we had a site just across the road that needed 21Mw of power and because we owned the transformers I had to get drops fron the power company.Finaly I got them to buy the substation and still got a good rate for having a 115Kv feed and did'nt have to have new drops put in for the other site .They could cross the road.
Regards,
Tom

BobB said:

THEY PROBABLY ARE.

Click to expand...

Correct!!!!

I have been investigating, will post more later!

Many years ago in Peoria (IL), we had a freq meter / strip recorder on the local utility. Amazing the variances that you would see. On Sunday mornings (like 3:00am) they would adjust for the week, so clocks would be right, more or less starting Monday morning. Many times, freq dropped as low as 38 cycles, to get the "avarage" in there.

Click to expand...

I have never seen the capability to change the frequency. Before digital displays became popular the generation systems I know had analog cycle meters that went from 59.5 to 60.5 with resoulution in the 100 thousands....very large display that rarely deviated from 60HZ dead center.

Many utility companies buy power from generating sources, my city buys from TVA and is its own utility company. There is no way for them to change the cycles.

I too have used strip recorders etc and have seen many things that shouldnt have been...but I have never seen cycles change on public utility. Having worked with gensets I know I could not run one of them at 38HZ and supply power to even a travel trailer, that would equate to approximately 76 volts. On a paralleled system that could be detrimental to the other systems involved on the grid.

Caterpillar has sold gen sets for many years. Its my understanding that during WWII they established a network of their sets that could assist utilities in a crisis. Its also my understanding they have maintained and enlarged that system but I am not familiar with all the details.

On Sunday mornings (like 3:00am) they would adjust for the week, so clocks would be right, more or less starting Monday morning. Many times, freq dropped as low as 38 cycles, to get the "avarage" in there.

Click to expand...

This certainly used to be the case in the UK, (the "used to be" because I've been living in Germany for the last 18 years), but the equalisation was on a 24 hr basis. As far as I'm aware, the frequency rarely deviated more than +- 1Hz.