UPS: when the grid goes down
Power provided by the grid is more than up to the job of powering lights and motors, but when you want to power tele- and data communications equipment, or if you are manufacturing microelectronics, you need to take the power that comes from the utility and clean it up.
The right kind of UPS (uninterrupted power supply) not only can keep the equipment running during a power failure, it can also provide a clean source of power.
The other UPS
Power disturbances can cause problems for many types of critical processes, particularly computers, servers, and phone systems that have become increasingly central to all business operations. While many systems are able to shrug off minor fluctuations, larger surges can bring these machines down to their knees. And when it comes to making something as delicate and involved as semi- conductors - especially when made on a large scale - the damage and financial loss that can result from a surge or even dirty power is, well, let's just say more than substantial.
"The ultimate industry critical in nature from a power point of view is the semi-conductor industry," starts Brad Roberts, Power Quality Systems Director at S & C Electric, manufacturers of UPS sytems. "Each little piece is very, very valuable. The process of making them is incredibly delicate. If the lights blink (meaning there's a power disturbance) for any of those companies, the result is just devastating. Hundreds of thousands of dollars are lost."
Roberts goes on to say that the critical nature of this market is such that its companies can’t depend on the quality of the electric power from the utilities. UPS was developed as a solution for these types of customers who simply can't have their businesses interrupted by an unknown power problem. "The utlity companies can't eliminate that problem after it's come 50 miles from the power plant. It's impractical to burry the whole electrical system, and even when its buried it still doesn't solve the problem exactly. For example, when people drill into the ground it will interrupt it." So using a UPS system provides a kind of protection the utility is just not equipped to offer.
HOW THE NEED CAME TO BE/The back story
ST Microeletronics in Phoenix, Arizona is using S&C Electronic's single largest UPS system. The same system is being used by Intel. Purchsed in 2002?, the system went online that summer. "Online UPS's are still the predominant solution in most computer centers," says Roberts. "Semi conductor factories use a mixture of online and offline systems. We're the leader in medium voltage equipment, and we're the only one that builds a large outdoor system."
Prior to purchasing S&C's UPS system, ST Microelectronics didn’t have any power protection. Needless to say, it was a costly situation. "In Phoenix, we're very susceptible in summer time to monsoons," begins Joe Murphy, Director of Site Facilities Operations at ST Microelectronics's Phoeniz office. "It could be a beautiful day and all of a sudden there's wind and storms. When those lightening bolts would strike, they'd hit power lines and you'd see interruptions and the tools would go down. Just one monsoon could cost millions if a lot of wafers are lost."
ST Microlectronics found itself losing a lot of wafers, and they were having to do a lot of reworks as well. That was time and materials lost. "We needed to find something that would protect the system so we could ride through these storms," Murphy continues. "Very seldom were these total power outages. Most of the time we'd see dips and spikes. But these are just as harmful because the tools that manufacture these wafers run off micro processors and they're very susceptible to power fluctuations."
"We were doing best they could to work with the local utility, but but unfortunately, with this kind of weather, there's not much they can do. The 230 KV lines are unprotected, they come into our distribution center, then we drop those down to 12470 V." Initially they considered using individual UPS systems at each tool, but there were just too many tools for that to be practical. "So we looked at alternative to having mulitiple UPS's," Then we came up with the S & C Electronics' UPS."
This UPS - the 12MW 12,470 V system- was far from cheap. At the time ST Microelectronics purchased it, it was $5 million, and since then they've added an additional $2.5 million to expand its capacity. The company, however, could justify the cost when they counted the number of wafers lost in comparison to cost of the unit. In the long run they came out far ahead.
The Search
Like any smart buyer, ST Microelectronics looked at different alternatives before they decided on S&C's UPS. This seemed to be the best choice for their particular needs. An alternative they had considered were generators with fly wheels on them. "We would not have had the size to have those," says Murphy. "We would've had to keep them running at all times, and they would be expensive and probably not that reliable."
ST's main goals were to find the most economical solutions that was both reliable and would be able to ride them through the majority of the interruptions. "We figured that we had to protect the whole manunfacturing area, and to do that we had to protect the whole building," says Murphy. "So we protected all the facilities related equipment and the manufacturing related equipment." Although ST had already been familiar with UPS - they've had UPS systems at other sites of theirs - they had never before had the opportunity to work with a system as big as S&C's before.
How it synchronizes with the grid
There are two ways to provide UPS: through online and offline UPS systems. Online systems remanufacture the power at the customer site. Traveling from the utility, the power gets dirty by the time it gets to the customer. Online systems regenerate the electricity at the building that needs it. "The system then takes that utlity power and basically regenerates it by running it through a rectifier to convert it to DC power (battery power)," starts Roberts. "Then you float a battery there and if anything goes wrong with the utility, the battery will take over. Then you regenerate the DC power into AC power, which is done in an invertor." Now there's clean power at the building.
With online UPS's, you don't know when a problem will happen, so the process of regeneration goes on all the time. The problem is, there's a cost that goes with it: inefficiency. "You lose energy when you rectify and more when you invert it," elaborates Roberts. "That degregation is called losses. When you stick power in you only get about 90% of it out. That means there's losses in the 6-10 percent range to generate that process. That's not so bad for something sitting on your desktop, but when you're talking about a large buildling, that can be hundreds of thousands of dollars a year lost."
So S&C went to work to create a more effective system geared toward businesses with large energy needs. Roberts continues: "We built, on a very large scale, an off line UPS system that allows the power to flow directly to the load from the utlity. Utility power is fine about 99.9 % of the time. To protect a big factory of the size we're talking about, you have to be very, very good at doing that and it's not easy. So we've perfected a system by which we can sense and turn on many thousands of kilowats of power in about 2-4 milosecond. This system comes out to be physically smaller because it doesn't have to have all that energy and capability on a continuous basis. And it's now 99% efficient."
Speed is of the essence
When the 12MW 12,470 V system senses any minor distrubance in any of the 3 phases of power, it automatically turns itself on and the utlity power off. The typical event only lasts for about a tenth to a half of a second. "What the utlity fixes in 50 miloseconds, our system fixes it in two," says Roberts. "We can protect it before damage is done.
ST MIcroeletronic's UPS is located in their substation, right inside the walls where the grid supply is. "Power is flowing through the system at all times, and the batteries always have a charge on them. When it's needed we have a fast switch and as soon as it sees an interruption, the power will go to the UPS system that will feed the plant. That happens within a quarter of a cycle."
Because it serves so many customers, the utlity can't put in equipment to protect only ST Microelectronics. Nor does it have the capacity to protect power so quickly. So each individual company has to put in their own system.
The huge savings associated with these large companies by using this kind of system is tremendous. "although this is not the case with ST," begins Roberts, "in some cases companies have very large generator systems, and if the system fails totally then our system runs the plant and then transfers it to the generator."
Size and capacity
For a company with medium voltage needs such as ST Microelectronics, Roberts says the most progressive choice would be to have a medium voltage system. "These companies are pretty unique. It makes more sense than low voltage. With bigger systems ou company is more cost efficient, not just in price but in operating costs. When a company like ST looks at their whole lifecycle cost, it makes more ssesne to buy a bigger system from us at medium voltage."
ST has UPS systems in every one of their factories, all of which are very large, typically several hundred thousand square feet of floor space. Some are even over one million square feet. "The loads in these facilities are probably in excess of 50 watts per square feet," says Roberts. "ST Microelectronics is 450,000 square feet; the main areas will be in 50 watts per square foot range. You need to protect that critical portion of the factory, where the tools are, the clean room, but not everywhere. At ST they did choose to protect the entire factory because that was the most expeditious way to get the job done. It was a retro fit."
Installing the goods
The installation process was done by S&C, a turnkey company who manufactures the product, installs it (by hiring outside contractors) and maintains it. The installation process did not affect the facility or workers, and Murphy maintains that it went quite smoothly. "We had a concrete pads reports, we had to do a tie into the electrical feeds, and all units had to be put together on the site. After they were tested in Milwalkee they were shipped here and then assembled again."
HOW LONG DID THIS PROCESS TAKE?
The only real concern ST had during the installation was schedule. "It seemed at first like it was getting delayed but we finally go that under control," says Murphy. And sure enough, in the end the timing worked out just fine.
Pricing and maintaining
Each individual company has different factors to consider when it comes to whether they can afford to purchase - or afford not to purchase - a UPS system of this capacity. "Typically if the pay back for the investment is not less than two years, companies won't do it. But if they're losing 10 million a year and the solution is 5 million, that would probably work." So the bottom line is, the more able a company is to calculate its losses, the better able they are to decide whether such a system is a worthwhile investment.
All systems of this nature require maintenance. In most cases, the customers depends on the supplier to provide it, and such is the case with ST Microelectronics and S&C Electric. "We have a miantenance agreement with S&C," says Murphy. "They come in periodically and adjust the machine, and this doesn't really distrupt it." But some disruptions, even when there's nice weather, just can't be predicted. Murphy recalls the following incident: "One time they were doing something to the system this past year and they took it off line. It was a sunny day, it was Valentine's Day, and someone had mylar balloons that hit the 230 KV lines. We heard a big bang with balloons." Unfortunately, that was one costly holiday for ST Microelectronics.
Roberts points out that one of the great thing about the Purewave 12MW 12,470 V system is that it only needs a major inspection once a year. "The customer has the responsibility of changing air filters and things like that maybe once a month. They also pay us to monitor the system remotely." S&C montors about 50 sites around the world. "Our computer system checks each one of those systems every night then reports if everything is fine, or if something happened at a site, like a thunderstorm and a disturbance."
All UPS systems have what is called a bypass. That means if the equipment develops a problem, it will take itself out of service and put the customer onto raw utility power. "The customers obviously don't like that," says Roberts. "They want a quick reponse, minutes at the most." If a malfunction occurs at a customer plant, we get notification via remote alarm system. S&C also sends service engineers, whoare on call 24 hours, there immediately." So if a system is down, it's not long before it's up again.
Expectations and results
For ST Microelectronic's, the decision to purchase the Purewave 12MW 12,470 V system was obviously a good one. It has definitely fulfilled the hopes and expectations the company had before buying it. "What we do is we measure the number of saves we have and every time the purewave system has come on, to dte we have about 112 saves in the fours years we've had it.
Has it ever not worked? Yes. 8 times. Not disappoitned because a lot of times the unit was offline when something happened.Always seemed to have work when it was online. We had a problem once when in this driving rain, the rain comes in sideways even, and it belw water into it and shorted out something. Hasn't let them down. Offline for maintenance, once was offline when replacing transformers, changing batterires, or upgrades to the system.
How big of a difference financially has it made for your company?
each savwse ia a good payback, but how much was the payback and hw much was the hit. in 01 and 03, the two worst monsoon season in awhile. Last years was mild. Saving millions in those years in particulat.
Being used elsewhere first?
Was it being used elsewhere? Not much, maybe once. We were one of the first one s and we were the biggest single one. Intel has had much success with them.
was apprehensive, not went forward because S and C was noted for their high quality and they stand by their product.
Even though hadn't used it it was the best suited for their needs too. HAve a lot of praise for S $ C for theit ethic approach. They're very ethical. If there's a problem, I know about it right away. They always try to update the system to make it even better. They do all so he never has to deal with outside party (me.)