UPS Systems - experiences sought

[ScottyUK]

Ladies & gents of this forum,

I'm in the process of developing a scheme to replace our undersized static UPS system (3pNE in / 3pNE out in the 60 - 80kVA range). I am especially interested comments from anyone with experience of the GE Digital Energy SitePro range, mainly with regard to product build quality, reliability and quality of support from the vendor.

I want a more objective view than I will get from the vendor and their agents.

 

[peebee]

I understand GE just bought their UPS company within the last year or so. That by itself would be enough to set off warning bells in my mind. You might want to double-check this.

UPS users hate whatever UPS system that last blew up on them. Unfortunately, beyond that, it's tough to get any real reliability information from vendors or users beyond anecdotal evidence that really has little statistical value.

I typically recommend clients stick with big names and well-established technologies that are in current use in other critical installations. I strongly recommend staying away from new names or "bleeding-edge" technologies, at least until they've been around for minimum 3-5 years and have made STRONG inroads into CRITICAL installations.

I'd suggest you call your vendor and ask him for a list of specific critical installations. And I'd define critical generally to mean banks, high-end security traders, some internet/communications companies, some Fortune 500 central data centers, and very few others. I would generally NOT include hospital installations (although they are slowly coming around) or small office installations in my definition of critical.

Tried-and-true is the name of the game. You don't want to end up beta-testing a new design.

Hope this helps.

 

[ScottyUK]

Hi Peebee,

Thanks for the observations. I think the GE rotary UPS business is the recent acquisition - it used to be a company called Eurodiesel, which was owned by the Seghers group. The Eurodiesel rotary equipment had a lot of the financial institutions as users, so they had a good history. GE's static equipment has been around a bit longer as part of GE, as far as I know.

I agree with your list of 'critical' installations. Anything involving huge amounts of money, basically! Unfortunately many of these installations are at the MW level rather than the mid-kW level, and so one must be careful when comparing the situations.

Scotty

 

[rbulsara]

I am with peebee on this 100%. GE static UPS is a relatively new item in the USA. I will be cautious.

Good history of rotary units by Eurodiesel have nothing to do with how good the static units are. Checking out with Owners of similar units is the best idea.

Like Piller makes very good rotary units, but their static units are not very popular.

 

[busbar]

One aspect that you would think would be 1980’s news is incompatibility of standby-generator-set excitation systems and the UPS as a load on those gensets. There still seems to be a few low-bid UPS vendors that childishly feign the universal availability of a “zero-impedance source,” and genset suppliers that have nothing but a “100% resistive load” mentality. Procurement specs must carefully spell out who is responsible for what in terms of interoperability, acceptability as a complete system and timely resolution if there are problems evident to the end user.

I partially agree that restricting bidders to mainstream brands is desirable, but it still seems that selection of “big name” equipment manufacturers on both sides does not automatically guarantee compatibility.

If you do not have explicit experience in this aspect, you are miles ahead retaining a institutionally oriented consulting-engineering firm that is keenly proven in airtight builds where this capability has been well demonstrated.

 

[ScottyUK]

rbulsara,

I wasn't attempting to imply that a good rotary manufacturer necessarily had good static range, or vice-versa, only to say that GE's most recent acquisition was its rotary operation.

busbar,

It was specific info on GE's range I was seeking, as the question had been asked of me and I had no answers. I'm familiar enough with UPS systems from a previous role with a consultant engineering company, but that doesn't help me answer specifics about equipment I'm not familiar with.

The warning about specifications and responsibilities for interoperability is very worthy - I know of several occasions where the situation you describe has arisen.

I guess I was hoping for some feedback from the owner-operators of the equipment in question via this site, rather than those that the vendor wishes me to get in touch with (i.e. the ones that haven't blown up ). If the product range is as new in the US as over here, then 'stay clear' may answer I'm looking for.

Scotty.

 

[peebee]

ScottyUK -- has the vendor put you on to any impressive installations yet? Can you name them, or at least describe the types of facilities?

 

[mpparent]

Gents,

Something else to think about....now the UPS manufacturers are saying that you must replace the AC and DC capacitors in the static units. I believe the frequency was around 3 to 5 years, but don't quote me on that. The point is the cap's are around $130-$250 per unit, depending on if it's AC or DC. Rotary units are looking better...

Mike

 

[alehman]

I've worked with several US manufacturer's products and seen failures with all of them at one time or another. One major manufacturer had problems with a bad batch of capacitors that required bulk replacement in units in service. They responded well once the problem was identified (which did take a while). A key consideration should be availabiltiy and quality of the manufacturer's service organization. Find out how they handle service and interview other customers.

 

[peebee]

Not to get too far off the subject, but since we're talking about bad caps now. . . .

I've seen UPS caps fail in very very bad ways. In particular, I've seen a 2N UPS installation where one cap failed, released ionized gas that spread into both enclosures causing arcing between the busses in both units, causing near simultaneous power outages at both UPS modules, damage at both modules, and loss of power to the critical load. Caps suck almost as bad as batteries, but all UPS's are more or less susceptible to capacitor failure.

 

[Laplacian]

In my experience, SCI systems have provided excellent reliability. We use only static ferroresonant systems for crucial TDC control backup up to 50KVA. Many of our problems with the SCI units is when we do a 10 or 20 year turnaround on the unit. The "newest" and "improved" cards reveal problems that weren't picked up in Q/A or testing. What is your application? 1 hour backup with no generation or 5 minute backup for standby generator?

Also, the UPS is only as reliable has the battery providing backup. Please disregard any good things you hear about VRLA, maintenance free or sealed lead-acid. Stick with a good wet or flooded cell battery. We have great experience with Enersys CC series and get 20+ years out of a string. That is with annual load testing to verify capacity.

I hear Gutor is a decent manufacturer for EU/AsiaPacific, though APC recently aquired them to make inroads into the US.

 

[alehman]

To continue the off-topic thought, interesting story peebee - i've had nearly the same thing happen while commissioning a large multi-module system. It tried to go to bypass which ended up taking whole system down and completely destroyed one 600kW module while backfeeding the fault.

 

[ScottyUK]

Hello Laplacian,

Application is power plant control room. Brief summary of proposed scheme is dual UPS's with 100% redundancy, one UPS fed from primary source, other from alternate source, generator supply to one or both UPS's on loss of either or both sources. Battery autonomy 15 mins from either UPS. Generator to support other systems in control room such as HVAC and lighting. Both are required as this is a sealed blast-resistant building due to our chemical industry neighbours.

I agree that flooded cells are probably the most reliable form of energy storage. We have a number of these batteries supporting essential services on our turbines. 11 years on the Chloride 800Ah cells and still good. Over here in Europe, not many UPS vendors in the small-medium size (80kVA) UPS market offer flooded cells, at least not as standard, because of the additional maintentance required. It doesn't bother me because we have the facilities, but I can imagine that many customers won't want the hassle.

I don't really want a custom design UPS because I have had almost totally negative experiences of custom-built UPS when compared with commercial 'off-the-shelf' designs, in terms of reliability, cost, and support. Sorry to make a blanket condemnation of all custom builders out there, but that's how my experiences have been up to now.

APC - an interesting case here, because I've had good reports of their equipment, but their sales people have resolutely failed to respond to my requests for information and for an applications engineer to discuss this project. I guess they have too much business already... and what really worries me is that their support guys are just as bad. Lousy sales I only have to live with once, lousy support is with me for a long time.


Scotty.

 

[Laplacian]

We are stuck with custom systems and currently have ~200 SCI units in the 10-30KVA range. The main reason is that off the shelf units from Toshiba or Mitsubishi are designed with a backup generator in mind. The DC bus voltage is high (270-405VDC). They string all those cells together for a minimal uptime using low life sealed cells. You can of course provide your own battery, but to get 1 hour from 30KVA requires significant space for 180 cells.

If you want a boxed solution and have space for the battery, Toshiba is very good. I've been to their facility in Houston, TX and was very impressed. I was also impressed by their Q/A program. Their website needs a little work though.

Contact Greg Mack for more information:
greg.mack@tic.toshiba.com
800-231-1412 x3604
713-466-0277
713-466-8773 Fax

http://www.tic.toshiba.com