Uninterruptible power systems (UPSs) have come a long way in the last decade--delivering more capabilities than ever at lower cost. Does your power protection strategy take advantage of the latest possibilities?
July 1, 2005
From the “brownouts” that rolled across California in the summer of 2001, to the massive outages that darkened Ontario and the northeastern U.S. on Aug. 14, 2003, it is clear that as much as we rely on the public utility grid it is vulnerable.
The blackout two years ago shut down more than 100 power plants in Canada and the U.S., knocked out power to 50 million people, and sparked the biggest monthly drop in economic activity in Ontario in more than a decade.
Although some analysts felt the Canadian economy could absorb the anticipated multi-million dollar losses, Anderson Economic Group considered all possible impacts and forecast a potential impact closer to $6.6 billion.
As electronic systems permeate every aspect of commerce and society, we have increased our reliance on electric power at the same time that our demands are undermining the ability of the power grid to supply it.
While government and public utility companies continue to work on strengthening the grid, private-sector organizations must take responsibility for guaranteeing critical power to their own operations.
No doubt your data centers and telecommunications networks are protected by uninterruptible power systems (UPSs), which protect electronic equipment from the caprices of utility power.
They perform two key functions — condition incoming power to smooth out the sags and spikes that are all too common on the grid and other primary sources of power, and provide “ride-through” power to cover for sags or short-term outages for 30 minutes to an hour.
They do this by dynamically selecting and drawing power from the grid, batteries, backup generators, and other available sources.
In the last two decades, UPSs have proven instrumental in protecting organizations from untold millions of dollars in losses that could have been caused by power problems.
The last few years have also witnessed major advances in the design and manufacture of UPSs. Innovations in processors and other components have dramatically increased their capabilities while reducing heat output and cost.
Below is a sampling of what you can expect to get in today’s advanced models.
Whether you’re selecting a UPS for a cost-conscious branch office or a large data center requiring “six-nines” reliability, there’s a configuration available with just the right performance and price point-often within the same model or family.
Today’s UPS designs benefit from advances in Digital Signal Processing controls (DSP), allowing the elimination of many of the bulky components typically found in UPS’s.
For example, with modern, space-saving UPS designs, you can deliver 1500VA in a mere one unit (1U) of rack height-just 1.75 vertical inches, including batteries, 3000VA range in only two rack units (3.5 inches), with batteries, or 80kVA power modules in just 4.1 square feet of floor space.
With more power in smaller packages, there’s more rack space available for other critical equipment, such as servers, disk arrays, and extra batteries, and more floor space available for service clearance and additional data centre racks
In addition to occupying less rack space, modern UPSs deliver significantly more real output wattage or more power to protected equipment for the same utility dollar.
The difference is a very high power factor, a term which simply defines the amount of wattage delivered per VA (for example a 1000VA UPS delivering 600 watts would be said to have a “.6 power factor”).
Most UPSs are promoted and priced based on their VA rating, but for today’s applications, the wattage rating is just as important.
Unlike five to 10 years ago when PC’s and servers typically demanded a very low (.5 to .6) power factor from the UPSs that powered them, today’s modern IT equipment have internal power supplies demanding a .8 to .98 power factor.
A UPS providing a high output power factor will be able to power more of these demanding IT loads than a UPS with a lower output power factor. This increase in power density’ is especially important given the high cost of data center floor space.
Modern UPSs can also deliver high efficiency ratings across all load ranges, which reduces utility costs and extends battery run times.
Higher system efficiency translates into cooler operating conditions, which extends the life of UPS components and increases overall reliability, availability, and performance.
Hot-swappable components: In a modular architecture, you want to be able to add or remove components as needed. In fact, the UPS should be designed to permit individual modules to be taken off-line for maintenance without removing the load from conditioned power.
With “hot-swappable” components, if a power module or battery requires service, you would just open a UPS panel or face plate, grasp a handle on the front of the module, and slide it out of its housing.
There is no need to power down the UPS or connected loads or remove the UPS from the rack. When a module is reinserted into that slot, the UPS auto-detects its presence and switches back to normal operations. There would be no disruption in service or protection.
In the past, UPSs relied on “trickle charging” of UPS batteries, a method that continuously runs low current to the battery. Over time, this method dries the electrolyte and corrodes the plates, reducing potential battery life.
Furthermore, because UPS batteries are valve-regulated sealed lead acid, there was previously no practical way to get advance notice that batteries needed to be replaced. You only knew when they failed.
Conventional trickle charging became obsolete with the introduction of a three-stage charging technique that can double battery service life and optimize recharge time.
It works like this: first, a rapid, constant current charge brings the battery to near full capacity in about three hours, and the batteries are then ‘topped off’ by low-current trickle charging for approximately 48 hours, which prevents over-charging.
The charger is then turned off for a rest period, and stays off until the battery is discharged by use or extended periods of non-use.
What this all means is that batteries are being charged only for a few minutes a day, on average, compared to all day, every day, for older type UPS systems. You only have to look at the longevity of car batteries, which get long rests whenever the vehicle isn’t running, to appreciate how much a rest period can extend battery life.
Temperature-compensated charging monitors battery temperature and uses sophisticated algorithms to adjust the rate of charge accordingly, which greatly extends battery life.
Battery monitoring: Older UPSs were managed locally or through simple connectivity and cryptic command-line interfaces.
Today’s UPSs provide high-end monitoring and management capabilities, with simple, intuitive, visual interfaces-over your company’s existing LAN or a secure Internet connection.
Using a Web browser or network management system (NMS), an administrator can shut down or reboot a remote UPS, perform remote UPS battery tests, and schedule shutdowns of UPSs and protected loads.
More sophisticated systems can direct a selective, sequential shutdown of loads, so that the most critical functions receive the best protection.
Even if administrators are at home, off-site, or attending to other tasks, they have at their fingertips the early indicators and tools they need to prevent system crashes, avoid data loss and corruption, protect hardware or firmware from damage and ensure trouble-free operations.
In top-of-the-line systems, power management software continuously monitors and diagnoses the state of the utility grid, batteries, and sources of power, together with the condition of the UPS’s internal electronics and even local environmental conditions.
You can generate predictive analysis of potential trouble (for example, current leaks that foreshadow the imminent failure of a capacitor or the insulation on a wire) and get automated notification and alarms through email, pagers, and the Web.
Progressive administrators can have enterprise-wide control of multiple UPSs from handheld wireless devices, receive alerts by e-mail or pager, and not only track past UPS performance but also predict the future.
Large enterprises can benefit from expert systems that proactively monitor and manage the complete facilities infrastructure, including HVAC, UPS, power distribution, generator, fire-detection, and security systems- hundreds of devices from many manufacturers.
If your UPSs are between five and 15 years old, consider re-evaluating your power protection strategy.
An internal or third-party power quality audit might reveal a compelling business case for upgrading existing UPS systems, even if they still have useful life.
You might very well find that with a modern UPS architecture, you can substantially reduce equipment and space requirements, utility bills, and cooling costs-quickly repaying the cost of a new UPS while benefiting from innovations that improve overall performance and usability.
Rob Woolner is the vice president of Eaton Power Quality Ltd., a provider of AC and DC power protection systems, power management software, and professional services, headquartered in Raleigh, N.C.