Power Conditioning Equipment

[racobb]

For the Utility Guys Here:

I have an issue where a fairly large (480 volt, 1200 kW) customer feels they have voltage regulation issues. PF averages 75 to 80%. The customer is served from 2 miles of 336 Al. OH line at 25 kV and a 2500 kVA padmount tx. We have recorded the voltage on 2 separate occasions at 1 minute intervals and found the service voltage to vary +/- 4 to 5 percent which we believe is pretty good and the levels are well balanced.

Probably a 3000 amp plus service.

Facility is located in the Southeastern US.

The problem appears that the customer has purchased some equipment that has a +/- 2% tolerance, to which we have told them that we could not gaurantee that level of swing on the system and they would need to install additional equipment to maintain their required level of voltage. The customer is asking for +/- 1% swing!

Aside from ideas anyone might have, I am also interested in others that have seen this issue and any equipment/mfg that might have been used to solve the problem.

Thanks in advance!
Alan

Alan

 

[davidbeach]

Point your customer to ANSI C84.1. If they are silly enough to buy equipment that requires tighter tolerances than C84.1, they can buy power conditioning equipment to provide what ever tolerance they want.

 

[cranky108]

Looks at first glance that your customer might be causing there own problems. First the size transformer and apperently being underloaded, they probaly have a motor starting problem, that a soft start would help. Also a power factor correction should be in order to help the situation.

But davidbeach is correct that utilities are not required to provide that level of service. However, many utilities do offer expanded service, like this, for an additionl price.

 

[racobb]

Thanks David and Cranky108. I have advised them of the ANSI standards and told them therein lies the problem. Also I have seen that the voltage is stable on motor starting. Unfortunately the oversizing is not that uncommon!

The problem is a bit sensitive as you might understand. The customer is unhappy, wants to expand, but says they can't as long as the voltage problem exists. As always they play the loss of jobs card.

Alan

 

[cranky108]

Where I worked before we just said talk to the commission about it. It usually died there.

Here it's a mixed bag, with complaints also making it into the papers, and irritating rate payers about shifting costs.

Small towns, and local coops are worse about things like bending over for larger businesses.

 

[racobb]

Has anyone recommended, installed, or seen specific manufacturer's equipment in use for this purpose?

Alan

 

[waross]

Remember, if you as the utility, you must install enough capacity to condition all the power used downstream.
If the customer installs conditioning equipment for just the problem machine, it may be of much less capacity, and much more economical.
If the customer wants premium quality power he may have to pay a premium price.
I would consider a two pronged approach;
1st, find a good negotiator to work with the customer.
2nd, apply to your regulatory agency for an amended tariff to recover the cost of supplying power at higher quality levels than presently specified, should a customer request request such service.
On the public relations front, rather than saying it yourselves, it may be better if a third party "discovers" that his business wants to unload his extra costs onto the community as a whole.
You may consider starting the process of seeking regulatory approval to raise the rates of all your other customers to pay for this installation. The PR may cause the customer to back off and if and when the regulatory body prohibits higher rates to pay for the installation, you can offer to install whatever the customer desires.
Question;
Do you install industrial services free or does the customer pay as in many jurisdictions? If the customer pays the original installation, you should be able to charge him for upgrades.
Once the customer realizes that he will have to pay, he will probably opt for the much less expensive course of installing his own conditioning equipment.


Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[racobb]

Thanks Bill,

We have about 4 options here:

Do nothing....probably NOT!
Customer installs, owns, and maintains equipment.
Utility installs, owns, and maintains equipment for a fee.
Utility installs, owns, and maintains equipment for free...not the recommended course of action.

We are already discussing the options with the customer, and of course they want it for free, but I am recommending that not happen.

Mainly looking for mfg's/equipment some of you may have experience with.

Thanks

Alan

 

[waross]

You haven't told us what is the equipment that as been installed. The manufacturer may have a voltage stabilizing option that the customer has chosen not to pay for. I woiuld be suggesting to the customer that he may purchase a UPS for the machine much cheaper than you can supply high quality power to the entire site.
This can't be the first bad experience that the manufacturer has had with such finicky equipment. That is the first place to inquire.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[racobb]

You are correct Bill, and I understand what you are saying, but for the moment I am wanting to see if anyone has experience with a manufacturer for 2000+ kVA voltage regulating equipment at 480 for an input of +/- 10% and output a +/- 1% or 2% level.

I have looked at the STACO Energy and UST equipment. Does anyone know of other vendors?

Thanks

Alan

 

[davidbeach]

Look at S&C.

 

[ScottyUK]

Watford Control in England might be worth a look given the exchange rates at present. They've been in the market for a long time - good equipment and knowledgable staff.


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If we learn from our mistakes I'm getting a great education!

 

[racobb]

Thanks to both of you....I will check them out!

Alan

Alan

 

[racobb]

David,
Didn't know that S&C was in that business, thanks for the info!

Scotty,
Looks like Waterford may not have a large enough unit, but thanks as well!

Alan

Alan

 

[ScottyUK]

Watford's EMS range goes up to 8MVA and they can do 0.1% regulation as a 'special'. Basic accuracy is 'only' 0.5% . I came across this brochure from a year or two ago while looking for something totally different.


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If we learn from our mistakes I'm getting a great education!

 

[racobb]

Yeah, I saw that they have a pretty tight output! Did not see one that big, but will keep them in mind.

Thanks

Alan

 

[ScottyUK]

There's a link on the bottom of my previous post - a bit more tech detail than on the web.


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If we learn from our mistakes I'm getting a great education!

 

[racobb]

Got it, and they have some big ones, but they do the European 400 volt thing.....Thanks Again

Alan

 

[alehman]

There's probably some room for voltage regulation with capacitors. An automatic capacitor system or SVC could be an option.

Alan
----
"It’s always fun to do the impossible." - Walt Disney

 

[xxjohnh]

Power factor correction seems needed what kind of power factor tarif do you have. This could be the solution.