Commercial voltage optimisation

[Tim]

Hi guys,

I am going down this afternoon (3pm) to look at a large supermarket that is having voltage optimisation installed (one of many more on a list) and the electrical firm doing it want to sub it out to company i work for. (The other company and mine have a long standing relationship of passing work across if they get busy)

There is a guy from the other company meeting us there to go through the project and i want to have a list of questions ready to make sure we are all clear on whats going to happen.

I have no experiance in fitting these devices, however i have read a bit about them.

Have any of you fitted these devices and if so did you have any problems? Can anyone see any potencial issues or recommend questions to ask?

All the details i have so far are that its a 'powerperfector' unit, there will be a gennie on site to take over while the unit is installed and it is going to be out of hours.

Thanks in advance for your help,
Tim

 

[Engineer54]

First and foremost, you want to see the proposed installation drawings for this installation and the if location is suitably sized and ventilated. If you (your company) need to start doing any initial design work, or there is no installation drawings, you'd be best to walk away....

 

[Tim]

First and foremost, you want to see the proposed installation drawings for this installation and the if location is suitably sized and ventilated. If you (your company) need to start doing any initial design work, or there is no installation drawings, you'd be best to walk away....

I am assuming that the design is taken care of by the other company, but i will check. You say the room needs ventilation, do these voltage optimersers give off a significant amount of heat then?

Cheers e54
Tim

 

[Brightspark2]

They don't work and they cause problems in my experience, mainly discharge lighting...

We've been removing them from service for companies who don't want them anymore. None of the promises were met, they saved no money and it was costing then more in what they had to pay to the company.

We bypassed them, the company who owned them didn't even want them back, said we could keep them.

 

[Engineer54]

I am assuming that the design is taken care of by the other company, but i will check. You say the room needs ventilation, do these voltage optimersers give off a significant amount of heat then?

Of course they do, how much depends on the overall rating of the things and what method they are using to maintain the reduced voltage.

 

[alasdairp]

Of course they do, how much depends on the overall rating of the things and what method they are using to maintain the reduced voltage.

Some also put quite a lot of switching noise on to the supply which can cause other problems with IT and other sensitive equipment that you will then have to solve. I am very wary of large units. Small ones (like UPCs) for computers and critical equipment are fine, but large-scale ones very dubious in my opinion. Better to negotiate a better supply with the DNO rather than try to improve a problematic supply privately on site. I suggest that your firm should be very cautious about accepting this contract job - especially as you have not got experience of such systems.
Alasdair (EMC and power-systems engineer rather than an electrician).

 

[Tim]

They don't work and they cause problems in my experience, mainly discharge lighting...

We've been removing them from service for companies who don't want them anymore. None of the promises were met, they saved no money and it was costing then more in what they had to pay to the company.

We bypassed them, the company who owned them didn't even want them back, said we could keep them.

Were the problems with new HF lighting ballests? Ive just done a quick bit of reading while im waiting on site that says they do not benifit from power optimisation and that they have a reduced luminosity due to the lower voltage.

Cheers,
Tim

 

[Brightspark2]

Were the problems with new HF lighting ballests? Ive just done a quick bit of reading while im waiting on site that says they do not benifit from power optimisation and that they have a reduced luminosity due to the lower voltage.

Cheers,
Tim

It wasnt squire no...standard ballasts...premature lamp failure, and many manufacturers lamps not working in the fittings...

 

[Engineer54]

Can't really comment on the HF Flu fitting side of things, but i can see where a supermarket would benefit from a well designed and constructed equipment system. Which would be the multiple refrigeration units, freezer units and store room cold stores, Air Conditioning and ventilation systems etc.

These supermarkets don't run the whole store on voltage optimisation only the larger heavy load equipment, predominantly where motor loads are involved. I can't really see standard ballasts and tubes having premature failures due to 220V, most of those products would be designed/manufactured to be capable of running over a pretty wide voltage range, after all most of Europe is 220 Volt. Manufacturers don't make any stuff purely for the UK market these days!!

 

[Rockingit]

OK, you've got me interested now. We've pretty much established that the domestic voltage optimisers are just snake oil, and given that we're not talking about PF correction in this instance....how come it's (maybe) beneficial here?

 

[Engineer54]

OK, you've got me interested now. We've pretty much established that the domestic voltage optimisers are just snake oil, and given that we're not talking about PF correction in this instance....how come it's (maybe) beneficial here?

Bit of a difference between domestic and commercial systems.

Domestic systems are only any good if they can cover the whole load and not go into a by-pass mode, as soon as the load gets anywhere near where it could start saving money!!
Unfortunately those domestic units that can be connected to the overall installation are far too expensive and therefore the payback periods are unrealistic for the general homeowner.

Commercial units are also expensive but are offset by various business tax offsets and other commercial incentives. Generally pay-back periods and reduced and quarterly electric bills can be much reduced. So overall the commercial systems are much more favourable, than any domestic user would ever see!!

 

[sibbits]

The site i work on had one of these units fitted, and we have had no adverse affects from fittings failing. The only real problems were settings on some controllers needed adjusting to the new stablised voltages. The units were fitted by other contractors before our main incomer so it took a bit of arranging with the power company to get the change over done. i guess the only persons who will see the real benifits will be the owners of this building who get the bills. It still throws me a bit to get such consistant readings when i check to see if something is live

 

[Rockingit]

Bit of a difference between domestic and commercial systems.

Domestic systems are only any good if they can cover the whole load and not go into a by-pass mode, as soon as the load gets anywhere near where it could start saving money!!
Unfortunately those domestic units that can be connected to the overall installation are far too expensive and therefore the payback periods are unrealistic for the general homeowner.

Commercial units are also expensive but are offset by various business tax offsets and other commercial incentives. Generally pay-back periods and reduced and quarterly electric bills can be much reduced. So overall the commercial systems are much more favourable, than any domestic user would ever see!!

OK, I can understand the economic argument IF..... surely, a fixed resistance is a fixed resistance, and a watt is a watt, so if voltage drops then current rises....and a watt is a watt.... so how does this save energy?? (Allowing for us not talking about PF correction, of course). Tony has written up on this subject elsewhere and about the time he experimented dropping TX voltages at the MV level, and in effective the MVA dial didn't move! I'm genuinely interested, not spoiling for an argument!

 

[Engineer54]

They won't save money on fixed resistance loads, that's why i concentrated on motor loads and the like. As you, myself, and others have stated, for domestic installations, they really are a bit of a dead duck. Especially those that go into a by-pass mode as soon as the load starts increasing and where they could be making a bit of a saving... lol!!

 

[Brightspark2]

Can't really comment on the HF Flu fitting side of things, but i can see where a supermarket would benefit from a well designed and constructed equipment system. Which would be the multiple refrigeration units, freezer units and store room cold stores, Air Conditioning and ventilation systems etc.

These supermarkets don't run the whole store on voltage optimisation only the larger heavy load equipment, predominantly where motor loads are involved. I can't really see standard ballasts and tubes having premature failures due to 220V, most of those products would be designed/manufactured to be capable of running over a pretty wide voltage range, after all most of Europe is 220 Volt. Manufacturers don't make any stuff purely for the UK market these days!!

If I remember rightly some circuits where getting less than 220....

Pretty sure that was part of the problem...don't hold me to it though, was a few years ago.

 

[Engineer54]

If I remember rightly some circuits where getting less than 220....

Pretty sure that was part of the problem...don't hold me to it though, was a few years ago.

If that ''Was'' the case, then the system was incorrectly set-up. As far as i'm aware, all the present voltage optimisation systems are based on providing a steady 380V 3 phase/220V single phase supply to connected equipments, that shouldn't be affected by increasing or decreasing loads etc.

 

[Brightspark2]

If that ''Was'' the case, then the system was incorrectly set-up. As far as i'm aware, all the present voltage optimisation systems are based on providing a steady 380V 3 phase/220V single phase supply to connected equipments, that shouldn't be affected by increasing or decreasing loads etc.

Volt drop?...

Set up or design. I doubt much is done. More approach client and say hey we can save you this much if you pay us this much. Then stick it in and move on. Money spinner. I won't tar everyone with the same brush though.

 

[westmac]

OK, I can understand the economic argument IF..... surely, a fixed resistance is a fixed resistance, and a watt is a watt, so if voltage drops then current rises....and a watt is a watt.... so how does this save energy?? (Allowing for us not talking about PF correction, of course). Tony has written up on this subject elsewhere and about the time he experimented dropping TX voltages at the MV level, and in effective the MVA dial didn't move! I'm genuinely interested, not spoiling for an argument!

If you're varying the voltage across a fixed resistive load, a voltage reduction will not result in a current rise. Fixed resistive appliances quote a power rating based on a nominal voltage, the resistance is the constant rather than the power consumption.

 

[Engineer54]

If you're varying the voltage across a fixed resistive load, a voltage reduction will not result in a current rise. Fixed resistive appliances quote a power rating based on a nominal voltage, the resistance is the constant rather than the power consumption.

In other words Rockingit, you'll just have to wait a little longer for the kettle to boil before you can have you're cup of tea/coffee!! lol!!

 

[Rockingit]

In other words Rockingit, you'll just have to wait a little longer for the kettle to boil before you can have you're cup of tea/coffee!! lol!!

Maybe. But the fridge that keeps the beer cool is on 24/7, so sod waiting for the kettle!