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Critical power: backup protection for your critical systems: your critical IT systems could be bombarded daily by nine different power problems. Generators and surge suppressors address only two of them. Find out how to protect systems from the full range of 'silent killers' that lurk in public utility power.

From the "brown-outs" that rolled across California in 2001, to the massive outages that darkened the north-eastern U.S. in 2003, it's clear that--as much as we rely on the public utility grid--it is vulnerable.

As commerce and society march deeper into the digitally dependent age, 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 need to work on strengthening the grid, private-sector organizations must take responsibility for guaranteeing critical power to their own operations.

How Prevalent is the Risk?

According to a study by National Power Laboratories (NPL), the average power customer location can experience approximately 24 power disturbances each month. According to EPRI (Electric Power Research Institute) research across all business sectors in 2001, the U.S. economy is losing between $119 billion and $188 billion a year to outages and other power disturbances.

Detectible power outages account for only a small percentage of those damaging and loss-producing power disturbances. Even under normal utility operations--with no storm or lightning in sight--enterprise IT systems could be bombarded daily by conditions that damage critical components.

Why Generators and Surge Suppressors Are Not Enough

Utility companies are not required to provide computer-grade power. The American National Standards Institute (ANSI), which coordinates and administers the U.S. standards and conformity assessment system, defines the acceptable voltage variation on the utility to be typically in the range of plus 5.7% to minus 8.3% from absolute specification.

For example, utility service with 208-phase voltage can actually range from 191 to 220 volts. That range may well exceed manufacturer specifications for servers, storage devices, and networking systems--which are getting more finicky with each advance in miniaturization and processing power.

"Even though vendor specifications may say that a particular device behaves properly between 100-130V, for example, in my empirical experience, the equipment starts having trouble whenever you drop out of the normal 110-128 range," says Jim McQuire of The Power Place, an Atlanta-based power quality audit and consulting group. "The farther you stray from that normal range, the more problems you have. If you have 100V coming in, the equipment is not going to perform up to specifications."


Input power is routinely plagued with power surges, sags, electrical noise, harmonics, load fluctuations, and other interferences. A commercial customer on typical utility power will be subjected to these power anomalies daily, and 4 to 15 complete outages per year.

The problems and risks are intensifying, for several reasons:

* Computing and networking technologies are becoming ever more sophisticated. Today's storage devices, servers, and network processors use components so miniaturized that they falter and fail under power conditions that earlier-generation equipment could have easily withstood. "Twenty years ago, equipment circuitry and components were bigger and could handle the heat associated with larger power spikes," McQuire said. "Today's generation of equipment is so much more sensitive to fluctuations in all environmental conditions, not just power. Older equipment might have been able to handle a 200V spike, for example, but it doesn't take much of a surge to wipe out a motherboard now."

* Availability is everything. Information systems are no longer an adjunct support infrastructure, as they were 20 years ago. IT systems are now the core of all business processes. If a mass storage device or server farm goes offline, or critical network connections go down, the enterprise cannot function normally or profitably. Every minute of downtime carries a greater penalty than ever before. In short, the cost of downtime has gone up dramatically. So has the likelihood of power-induced failures. Clean, uninterrupted power is critical.

Most network providers have backup generators that provide emergency power within 10-30 seconds and surge suppressors that absorb potentially harmful electrical spikes, such as those caused by lightning. However, these are band-aid solutions for systemic problems:

* Backup generators address the most obvious power problem--complete loss of utility power--but provide no protection against the other power disturbances. It's not enough to switch to backup power in 10 seconds, when that interval is enough to lock up a server that runs critical enterprise applications, or to lock up networking systems and fail to deliver up to SLAs (service level agreements). Even a brief power disturbance can trigger events that result in hours of downtime before equipment can be restarted.

* Surge suppressors address the power surges, while having no effect on the under-voltage and variance conditions that can erode equipment health over time, or zap it in an instant.

* Uninterruptible Power Systems (UPSs) augment and supersede these power-protection strategies. UPSs can protect equipment from the full range of potential power anomalies--not just outages, surges and spikes.

Invisible power anomalies can be silent killers--causing insidious damage to critical IT systems and interruptions in essential enterprise processes.

Continuous, Clean Power for Always-on Networks

At its most basic level, a UPS performs two primary and complementary functions:

* "Conditioning" incoming power to smooth out the sags and spikes that are all too common on the grid and other primary sources of power

* Providing "ride-through" power to cover for sags or short-term outages (say, 30-60 minutes), by dynamically selecting and drawing power from the grid, batteries, backup generators, and other available sources

Three key types of UPSs are in use today:

* Standby UPSs are an economical solution for applications that need only minimal power protection. With a standby UPS, the protected equipment runs off normal utility power until the UPS detects a problem, at which point the UPS switches to battery power. Standby UPSs are best suited for home and small office computers.

* Line-interactive UPSs regulate voltage by boosting input utility voltage up or moderating it down as necessary before allowing it to pass to the protected equipment. These UPSs are often used with non-critical enterprise devices, such as small communications systems, limited workstation environments, and hubs and routers that are also protected by redundancy and alternate routing.

* Online UPSs continuously condition incoming power to deliver clean, perfect sine-wave power for protected equipment. Online UPSs completely isolate equipment from raw utility power and all its irregularities-and therefore represent the only real choice for critical IT equipment, such as mass storage devices, server farms, and data networks.

Advancements in computer chips and other components over the past decade have dramatically increased the capabilities of UPSs while reducing heat output and cost. These technology advances made online UPSs applicable for a much broader range of applications. Today, approximately 95% of UPS dollars are invested in online systems--a figure that has risen more than 15 points since 1998 and is not expected to abate.

Within any one of these categories, systems can be configured for a broad range of output capacities, and multiple units can be deployed to accommodate loads up to megawatts. In this modular architecture, one can add or remove components as needed. In fact, the system should be designed to permit individual modules to be taken off line for maintenance without removing the load from conditioned power.

Power management software can orchestrate the graceful shutdown of critical systems when power outages extend beyond the limits of backup systems. More sophisticated systems can direct a selective, sequential shutdown of loads, so that the most critical functions receive the best protection.

Power management systems continuously monitor and diagnose the state of the grid, batteries, and power sources, together with the condition of the UPS's internal electronics. High-end management systems also provide predictive analysis of potential trouble (for example, current leaks that fore-shadow the imminent failure of a capacitor or the insulation on a wire) and automated notification and alarms through e-mail, pagers, and the Web.

Delivering Confidence

Many organizations that rely on electronic systems are not fully aware of the potential for power problems until they happen--and then it's too late.

Are power specifications required by your electronic systems being met? Is the internal power infrastructure delivering up to specs? Are grounding issues causing hidden problems? A power quality audit will answer those questions, and more--identifying problems that could undermine critical electronic systems and providing clear guidance on appropriate power protection strategies for your needs.

From manufacturing systems to information systems, communication networks to physical transport networks, across all types of equipment and industries--whatever the infrastructure in question, proactive planning and the right UPS can prevent the potentially devastating consequences of power disturbances.

[c]Powerware, 2004

Darrick Finan is director of product management at Powerware (Raleigh, NC)
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Title Annotation:Disaster Recovery
Author:Finan, Darrick
Publication:Computer Technology Review
Geographic Code:1USA
Date:Jan 1, 2004
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