Surge-suppression technology

Increasing demands for uptime create challenges for telecom professionals across a wide range of systems and applications. Perhaps the most critical needs involve the decentralization of wireless applications and electronic equipment that is housed in remote telecom shelters.

Protecting against power outages and fluctuations is the first line of defense for today's wireless telecom environments.

Increasing demands for uptime create challenges for telecom professionals across a wide range of systems and applications. Perhaps the most critical needs involve the decentralization of wireless applications and electronic equipment that is housed in remote telecom shelters.

Some studies suggest that although a typical facility experiences power outages only a few times a year, power fluctuations occur almost every day. Proper electrical power travels as a perfect sine wave. The appropriate application of transient-voltage surge suppression can protect anything, from a single server to an entire building, and maintain that power wave form.

Today's surge suppressors can be the first line of defense for cable, data and electrical lines. Facility managers and technicians need to know the causes and consequences of power problems, and they need to be familiar with the latest technological advances in surge suppressors to protect their applications.

Examining your environment

Power problems can stem from a surprisingly wide range of sources. Many of us automatically think of the weather-related causes associated with power outages. It's true that, other than natural disasters, lightning and wind associated with major thunderstorms represent the primary threats to power quality. However, the increasing number of aging utility systems also creates risk.

For the most part, today's utility systems were designed for an industrial era, not for our information-intensive age. They cannot be counted on as a reliable source of network-quality power. As power plants age, supply margins dip dangerously low.

The limited number of power plants is a problem, as well. The farther away a facility is from the power source, the greater is the risk of power-quality problems. This is especially true in areas where power is distributed along a single line for which there is no backup.

There are other, lesser-known sources of power interruptions to consider. According to some studies, about three-quarters of all power disturbances are caused by equipment inside the same building as the affected system. Disturbances at centralized, subscriber-based operations, for example, can be created by the routine operation of office equipment in the building, such as laser printers, elevators and copiers.

The problem becomes more complex in remote telecom shelters where process equipment operates in a particularly close or confined area. The delicate circuitry of sophisticated telecommunications equipment required at cellular or PCS sites is particularly sensitive to its environment.

Perhaps most surprising of all, the very entity that you are trying to protect — the network itself — can be the source of many problems. This can be of concern in the high-growth areas such as wireless applications. The larger and more complex the network is, the greater is the risk of internally generated power disturbances.

Also, numerous outside connections (modems, hubs, routers, and multiplexed data lines) increase the risk of intrusive disturbances. Modern protection strategies must also encompass the protection of a “mixed bag” of systems and related equipment (e.g., Internet service-provider equipment operating alongside broadcast subscriber applications). Numerous services tend to congregate in remote shelters, as telecommunications and information technologies continue to converge.

Just as problems stem from a variety of sources, today's networks are also vulnerable to a widening variety of disruptions. Outages account for about 5% of all power disturbances. The vast majority of disturbances are caused by over- and under-voltage conditions. Beyond blackouts and brownouts, variations from a perfect sine wave can trigger a host of unwanted consequences.

Surges or swells caused by rapid reductions in power loads can damage sensitive hardware. Noise on a data line can result in a range of exasperating errors in data transfer including program crashes, data corruption and damage to computer power supplies.

Even seemingly insignificant or temporary spikes, sags or waveform distortions caused by your telecommunications network, or other equipment in the building, can be passed along power or communications lines.

Total protection for networks

While there are no hard-and-fast rules, consider which operations you want to have “up and running” and which need to be active to avoid much more than frustration and inconvenience. The most recent edition of the IEEE Emerald Book, for example, states that “A listed and properly rated surge-protective device should be applied to each individual or set of electrical conductions (e.g., power, voice and data lines) penetrating a structure.”

Surge suppressors were originally designed to prevent what are potentially the most destructive power disturbances: sudden spikes that damage microprocessor circuitry. In general, surge-suppression devices give cost-effective protection for stand-alone peripherals, modems and similar equipment.

Yet today, the best surge-suppression units are robust enough to stand up to a lightning strike and to protect the highly sensitive circuitry and hardware of microprocessor-driven telecommunications equipment. Some application-specific models are used in critical applications, such as those equipped with special filtration for the extra-sensitive equipment found in a medical diagnostic imaging center.

An appropriate TVSS system can protect anything, from a single server to an entire building. The same technology that protects extra-sensitive medical equipment also makes an ideal protection device for high-speed routers. This is because the high-frequency noise filter of a TVSS not only detects but actually “clamps down” on small surges, minimizing interference with normal utility power.

Instead of cutting off power disturbances, the TVSS continuously limits distortion at every point of the sine wave, whether it's a surge or spike. This unique filtration feature is one of the few methods of limiting ringwaves — the associated aftershocks of a rapid reduction or increase in the power load.

Small TVSS units can be mounted to electrical distribution panels to protect both linear and non-linear loads from being damaged by transients and line noise. These units are designed to limit the peak amplitude of large surges on telephone and data lines while eliminating smaller power glitches. Through detection circuits, these units send alerts for all failure modes to external alarm lights. In addition, advances in sine- wave tracking circuitry provide high-frequency noise filtering.

Grounding: Foundation of success

However, the effectiveness of even the most advanced surge-suppression device depends as much on how it is grounded and installed as on the technology itself. Before installing any power-protection device, a thorough site audit needs to be conducted that includes other less-obvious factors that contribute to interrupted service. These may include ground-impedance factors such as the type of soil, the humidity and the methods of grounding used.

Proper grounding is, quite literally, the foundation of a good power plan. Take for example, the ground wire used for all electronic systems as a signal reference. If this wire is in any way compromised, much more than signal confusion may occur; the potential is there for actual system malfunction.

Supporting the future today

Telecommunications has never been more critical to the operation of the modern enterprise, from a steady reliance on broadcast subscriptions to the dramatic increase in cellular users. The growth and complexity of telecom applications has sharply increased, with no end in sight.

A proper support program ensures that those users counting on the cable or electrical lines aren't left stranded, waiting for a business lifeline to come back to life. First, a good support program should extend throughout the life of your power-protection decision, from pre- to post-purchasing. A proactive program includes everything from fulfilling product warranties to site audits to the total management of the surge-suppression installation.

Many telecommunications managers are incredibly busy, so outsourcing support services may be the answer. The right outside resource can provide critical after-sale training, maintenance, technical support, repair and analysis. The service provider must be able to respond quickly, so single-source accountability is a key attribute. Look for a supplier with access to a large product line and with the local expertise to tailor a solution to your specific needs.

Demands on data/telecommunications equipment have made “no downtime” the goal. The latest surge-suppression technology can play a critical role in keeping these high-speed sensitive systems and components up and running. But these latest devices must be part of a total package of site analysis, selection, installation and support to be effective.

Bauer is president, Americas, of Liebert, Columbus, OH. For more information, visit or call 800-879-9222.

What is a surge-protection device?

A surge-protection device is a non-linear, voltage-dependent component, connected in parallel with the load, that is automatically resettable and limits follow-current. It can be connected between any current-carrying conductor or between any conductor and ground, per National Electrical Code Article 280.

An SPD protects the electrical system by limiting surge voltage while diverting surge current.

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