High-tech buildings need uninterrupted power

High-tech buildings need uninterrupted power

Michael Cahn

The advance of high tech equipment in the office demands a serious look at the need for uninterrupted power supply (UPS), an electrical system that enhances and regulates utility power and makes it more compatible with computers and sensitive electronic hardware. Unlike conventional lighting and simple appliances, superchips that drive computers and LANs (local area networks) require clean, continuous power.

In response, building owners and managers are placing an increasing emphasis on power planning to achieve high-quality power and stand-by capability in the event of a utility power loss. Most of us assume that power from the street is clean and perfect, but in terms of critical power – i.e., power used to drive computers – utility power carries a number of potential problems.

What do we mean by clean power? High-quality clean power is power that is free from outages, sags and surges, and voltage impulse activity. Impulse activity is created by utility switching and everyday off and on switching of equipment. When sags, surges and impulse activities constantly occur, they become detrimental to computer operations and to the useful life of equipment. Computer equipment and the superchips they run on are adversely affected by these impulses, causing premature deterioration that shortens their life spans. Ultimately, this affects a company’s bottom line, considering the cost, for example, of replacing 4,000 PCs after four years when they were expected to last for 10 years.

Dips in power supply also affect office operations, especially time spent on retrieving and replacing data that gets lost as a result of outages. Anyone who operates a computer is all too familiar with the frustration of those dreaded “glitches” that result in loss of individual bits of data.

What is UPS?

Basically speaking, UPS acts as a filtering system to clean and regulate power that comes from the street. The most popular type of installation is a static system. It is called an “online system” because it runs continuously without interruption. Totally automated, the system switches from utility to UPS power and handles all problems by itself. If something goes wrong, it sends its own alarm.

The static system works to enhance utility power by putting it into a rectifier which changes the AC power to DC power. The DC power is put on a DC bus (conductor) which in turn feeds into an invertor. The invertor is the most important part of the system because it filters the power and changes it back to AC power. The DC bus is also connected to a battery system that provides temporary backup during power failures (until the generator takes over). The rectifier feeds the invertor and charges the batteries. Extra features that provide the system with additional options include generator backup, automatic transfer switch (ATS), which is required for a generator, and a power distribution unit (PDU).

Buildings with tenants that rely heavily on computer operations and electronic equipment should only consider an online system (as opposed to an off-line system). Since the introduction of the on-line static UPS system, the cost of installation has become competitive with the cost of other protection. Because every building has a different load profile, the cost will depend on each individual situation.

UPS systems are generally installed independent of other electrical systems, with the critical load intercepted at a point determined by the practicality of installation. It is now possible to place a static UPS unit in the same room as the computer equipment representing the critical load. For example, a manufacturing company in New York City recently had a static system built right in its computer room, approximately 300 square feet in size. Other systems may take up an entire floor.

Assessing the Need For UPS

When building owners and managers are faced with the planning and implementation of power upgrades, it is time to consider installing UPS to back up and regulate utility power. An electrical consulting firm that specializes in Power Quality Management (PQM) can determine the need for UPS and the type of installation required. The consultant conducts a power quality survey (PQS) to assess the electronic equipment in the building. The survey includes activities over a period of a month or longer, which allows the consultant to see patterns in power usage as well as problems. Recommendations will be based on the building’s history of power usage and how power is planned to be used in the future.

As computers become faster and more powerful, UPS will become as essential to some office operations as fluorescent lighting and telephones. Buildings with high-quality and abundant power supply will be easier to market because they allow tenants to perform at the most optimal level.

COPYRIGHT 1994 Hagedorn Publication

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