TOC \o "1-3" Power Protection: Delivering the High 9s PAGEREF_Toc493936346 \h 08D0C9EA79F9BACE118C8200AA004BA90B02000000080000000E0000005F0054006F00630034003900330039003300360033003400360000000000

Tutorial Introduction: Power Protection: Delivering the High 9s PAGEREF_Toc493936347 \h 08D0C9EA79F9BACE118C8200AA004BA90B02000000080000000E0000005F0054006F00630034003900330039003300360033003400370000000000

Tutorial Outline PAGEREF_Toc493936348 \h 08D0C9EA79F9BACE118C8200AA004BA90B02000000080000000E0000005F0054006F00630034003900330039003300360033003400380000000000

Objectives PAGEREF_Toc493936349 \h 08D0C9EA79F9BACE118C8200AA004BA90B02000000080000000E0000005F0054006F00630034003900330039003300360033003400390000000000

Issues in Power Protection PAGEREF_Toc493936350 \h 08D0C9EA79F9BACE118C8200AA004BA90B02000000080000000E0000005F0054006F00630034003900330039003300360033003500300000000000

The True Cost of Downtime PAGEREF_Toc493936351 \h 08D0C9EA79F9BACE118C8200AA004BA90B02000000080000000E0000005F0054006F00630034003900330039003300360033003500310000000000

Power Solutions for Mission Critical Applications PAGEREF_Toc493936352 \h 08D0C9EA79F9BACE118C8200AA004BA90B02000000080000000E0000005F0054006F00630034003900330039003300360033003500320000000000

Using Surge Suppressors PAGEREF_Toc493936353 \h 08D0C9EA79F9BACE118C8200AA004BA90B02000000080000000E0000005F0054006F00630034003900330039003300360033003500330000000000

Using Uninterruptible Power Supplies (UPSs) PAGEREF_Toc493936354 \h 08D0C9EA79F9BACE118C8200AA004BA90B02000000080000000E0000005F0054006F00630034003900330039003300360033003500340000000000

Power Management Features of UPSs PAGEREF_Toc493936355 \h 08D0C9EA79F9BACE118C8200AA004BA90B02000000080000000E0000005F0054006F00630034003900330039003300360033003500350000000000

AC and DC Power Coming Together PAGEREF_Toc493936356 \h 08D0C9EA79F9BACE118C8200AA004BA90B02000000080000000E0000005F0054006F00630034003900330039003300360033003500360000000000

Power System Configuration PAGEREF_Toc493936357 \h 08D0C9EA79F9BACE118C8200AA004BA90B02000000080000000E0000005F0054006F00630034003900330039003300360033003500370000000000

Power Service and Support PAGEREF_Toc493936358 \h 08D0C9EA79F9BACE118C8200AA004BA90B02000000080000000E0000005F0054006F00630034003900330039003300360033003500380000000000

Tutorial Summary PAGEREF_Toc493936359 \h 08D0C9EA79F9BACE118C8200AA004BA90B02000000080000000E0000005F0054006F00630034003900330039003300360033003500390000000000

Tutorial Introduction: Power Protection: Delivering the High 9s

Welcome! To ensure the appropriate level of high availability and reliability for powering critical telecom applications, service providers must consider a combination of the right technology, the right configuration of that technology and the right staff or contract maintenance to support the system once it is in place.

Tutorial Outline

We'll talk about these issues in ten short lessons.

  1. Issues in Power Protection
  2. The True Cost of Downtime
  3. Power Solutions for Mission Critical Applications
  4. Using Surge Suppressors
  5. Using Uninterruptible Power Supplies (UPSs)
  6. Power Management with UPSs
  7. AC and DC Power Coming Together
  8. Power System Configuration
  9. Power Service and Support
  10. Tutorial Summary


When you have completed this tutorial, you should be able to achieve the following objectives:

  • Given a desired system reliability percentage, correctly identify the power solution required to achieve that reliability.
  • Given a list of functions, correctly identify the functions of surge protectors.
  • Given a list of features, correctly identify the features of UPSs
  • Given a list of features, correctly identify the management features UPSs can provide.
  • Given a power system, correctly identify the configuration required to provide power redundancy to that system.
  • Given a list of steps, correctly identify five power maintenance steps that providers can take to prevent downtime.

Issues in Power Protection

Heightened demand on telecommunications equipment has led service providers to seek single-source solutions that address complete power protection for all types of systems. Such systems range from central offices with large switching equipment to remote telecom shelters that require advanced control and site monitoring capabilities.

In addition, the need for continuous availability for telecom, IT and facilities managers who must support these systems continues to increase with the explosion of the converged data and voice market and the growth of dot-com organizations and e-commerce applications.

The challenge for today's telecom manager is to develop a holistic approach to power protection that provides the centralized environment of the traditional data center safeguards, including power protection, monitoring, cable management and security, without the physical limitations of the data center itself.

Service providers could follow a more comprehensive approach that takes into account the appropriate protection equipment, site evaluation and proper maintenance. One option for providers is to identify and configure a protection strategy geared toward telecom applications that suits the organization's processing demands and systems availability requirements.

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The True Cost of Downtime

How much does it really cost an operator when the network crashes because of power glitches? Although an exact figure is hard to compute, the real loss is probably much higher than most service providers expect.

One way of defining high availability is to categorize the impact of unavailability on business activity. One independent research and consulting group has identified six distinct availability environments along these lines. These environments range from disaster-tolerant levels where systems failure must be invisible to the user to fault-resilient operations that require uninterrupted computing services during essential time periods.

Table 1 (below) provides some real-world examples of the financial impact of one hour of downtime, according to Contingency Planning Research.

Business Operation

Hourly Financial Impact (Range)

900 number services

$54,000 - $70,000

Range attributed to promotions

Airline reservation center

$67,000 - $112,000

Range attributed to travel/promotional months

Cellular (new) service activation

$38,000 - $44,000

Range attributed to peak activation periods

Credit card sales authorizations

$2.2 million to $3.1 million

Range attributed to seasonal shopping

Home shopping channels

$87,500 - $140,000

Range attributed to seasonal, promotional programming

Infomercial 800 number promotion

$175,000 - $224,000

Range attributed to seasonal, promotional programming

Online network connect fees

$23,500 - $27,000

Range attributed to cost of connect fee

Table source: Liebert

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Power Solutions for Mission Critical Applications

Mission-critical telecom systems require advanced power protection for their continuous operation, especially in areas where much of the business backbone depends on communications and data transport. Often, nothing less than 24-hour demands on servers, e-commerce/Internet applications and data/telecom equipment have made the "no downtime" operating parameter a primary goal.

For mission-critical systems where the consequences of failure would be catastrophic, the answer lies in improving power availability to the critical equipment. Consider, for example, the difference between five 9s uptime (a system with reliability of 99.999%) and an environment that demands 24-hour protection. A single percentage of downtime may seem benign, but it is enough time to translate into disaster in some industries. Six 9s (99.9999%) is the starting point for the networked economy players

Table 2 (below) illustrates what these percentages equate to in disruption to power and the recommended protection scheme needed for the corresponding levels of reliability.


Disruption per year

Protection Scheme*


88 hours



8.8 hours

+ backup power


0.88 hours

+Uninterruptible Power source (UPS)


5.3 minutes



32 seconds



3.2 seconds

+services, precision air conditioning

*Continuous systems availability can only be achieved with complete infrastructure support. This includes power protection, precision air conditioning and a way to monitor equipment, even from a remote location.

Table Source: Liebert

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Using Surge Suppressors

Surge suppressors are essential for any carrier network. Surge suppressors originally were designed to prevent what are potentially the most destructive power disturbances: sudden spikes that damage microprocessor circuitry. Some of the more advanced surge suppression units are robust enough to withstand the devastating power of a lightning strike and protect highly sensitive circuitry and hardware.

The appropriate line of transient voltage surge suppression can protect anything from a single server to an entire building.

The same technology that protects extra-sensitive equipment in a medical diagnostic imaging suite also can protect the high-speed routers in telephone lines such as centralized PBX operations, modems or KEY systems. This is because the high-frequency noise filter of transient voltage surge suppression not only detects but also clamps down on small surges, minimizing interference with normal utility power. Instead of cutting off power disturbances, the unit continuously limits distortion at every point of the sinewave, whether it's a surge or spike. This filtration feature is one of the few methods of limiting ringwaves, the associated aftershocks of a rapid reduction or increase in the power load.

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Using Uninterruptible Power Supplies (UPSs)

Another essential element for today's power system is an Uninterruptible Power Supply (UPS). Today, manufacturers offer a wide range of UPSs and related protection equipment for about every environment. What is appropriate for an isolated workstation or PC--that is, a small stand-alone UPS--would not be an efficient solution for network nodes clustered in the same office.

A separate UPS stationed at every node on this type of network represents a more costly proposition than connecting the network to a large, full-featured UPS. The quality of the protection can be compromised significantly with the stand-alone solution.

For mission-critical applications, the power configuration becomes more complex. First and foremost, the UPS should be online. As opposed to an offline or a line-interactive UPS, an online system eliminates a wider range of potential power problems such as spikes, surges and difficult-to-track harmonics that are common with standby generator operations. The online UPS continually recharges the battery so if power goes down, backup is immediately available.

Some UPS designs feature hot-swappable batteries to ensure maximum system availability--even during routine maintenance. Service providers should remember that different applications have different needs; with a network server, a graceful shutdown may be all that's required. A telecom system, however, may need longer autonomy times that require extra batteries, or a standby generator.

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Power Management Features of UPSs

Today, power protection extends beyond power quality to control over power quality. An Uninterruptible Power Source (UPS) can play an active part in the power management process, provided it is equipped with the appropriate connectivity and communications capabilities. Shutdown abilities can range from performing routine alerts of imminent power loss to load shedding and staged shutdowns from a single location to turning off non-essential applications from a facility-wide UPS to save battery time for vital servers.

Users need to be alerted to a problem before the power aberration or equipment failure. One method is through today's system of UPS alarm and on-screen messages. It now is possible to supply event-specific alarm messages that provide instant recognition of a power problem. These messages can be sent directly to certain areas so that an engineer can respond to and resolve the problem before any business disruption occurs.

Different types of UPS communications also are available in a redundant form--that is, they are designed to provide multiple solution paths in the event of a problem. An example of this is the in-band/out-band redundant communications strategy. In this strategy, the UPS provides out-of-band communications separate from the network wire, ensuring emergency contact with administrators or the equipment manufacturer even in the event of network failure.

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AC and DC Power Coming Together

With the convergence of data and voice communications, today's mixed network environments often require facilities managers to accommodate equipment that requires an AC and a DC power source.

The AC power can be derived via inverters powered from the -48 VDC power system. An alternative is the use of an AC Uninterruptible Power Source (UPS), which is often more straightforward, efficient and costs less. Compared with DC systems, an AC UPS uses higher-voltage batteries, provides regulated voltage output, is available in higher power capacities and allows for longer power distribution distances.

But it isn't as simple as placing any AC UPS into an existing setup. As networks grow, power quality and reliability factors become much more complex issues. It is important that the AC UPS provide power as reliably as the associated DC power system. In many systems, the DC-powered equipment is not fully operational without the AC-powered equipment and vice versa. Therefore, it is important to take a total systems approach. Figure 1 illustrates the evolution toward a converged networked economy, which is especially true for telecom applications.

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Power System Configuration

The way in which a power system is configured--even within a controlled environment--remains the critical difference in availability. System configuration makes the difference between five 9s and total assurance of power in virtually every circumstance.

To avoid compromising the availability of load equipment, the power system needs to be about 10 times more reliable than the load equipment. Therefore, service providers require redundancy in their power systems. Critical telecommunications and IT equipment that features dual input power connections can help facilitate the implementation of such redundancy.

In its basic form, distributed redundancy involves creating two redundant power protection system busses and redundant power distribution systems. This eliminates as many single points of failure as possible, all the way up to the load equipment's input terminals. To provide fault tolerance, some method of allowing the load equipment to receive power from both power protection busses must be provided.

To protect against fast power-system failures, such as circuit breaker trips or a power system fault, either dual input load equipment or very fast transfer switches need to be applied between the two independent power sources to eliminate any common failures.

Several distributed redundant power distribution configurations have been devised. For today's large convergent telecom facilities--that is, those with large, high-availability IT equipment--carriers have deployed dual redundant UPS systems with redundant AC power distribution.

With large, convergent telecom facilities, an emerging power system configuration involves using small distributed, redundant DC rectifier systems supplied from large dual redundant AC UPS systems. Small, self-contained DC rectifier systems along with AC power distribution units can be located throughout the IT data center to supply either AC or DC power to the load equipment.

The best practices of large IT data centers are merged with the DC power systems of telecom facilities to optimize the cost and reliability. Redundant, standby generators can provide dependable power in the event of a sustained commercial AC power failure.

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Power Service and Support

Choosing the right power configuration doesn't end with the sale. Specifying and maintaining a high level of power availability means that carriers must have access to several support services.

Preventative maintenance is critical to the long-term effectiveness of a power protection program. This includes:

  • testing equipment regularly,
  • checking the battery plant,
  • verifying that the Uninterruptible Power Supply (UPS) and rectifiers are operating properly, and
  • taking a thermographic survey of selected equipment and connections to prevent failures in the electrical systems.

Telecom sites--particularly if they are unmanned or remote--need thorough periodic reviews.

Contracting support services can help ensure 24-hour operations as well as provide critical after-sale training and maintenance expertise. The service provider has to respond quickly, whether the replacement entails a small, single-phase UPS within 24 hours or faster response for larger units protecting mission-critical systems.

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Tutorial Summary

In this tutorial, we took a comprehensive approach to providing continuous power; an approach that takes into account the appropriate protection equipment, site evaluation and proper maintenance. The costs of downtime are high, both for mission-critical applications and business applications.

Continuous systems availability can only be achieved with complete infrastructure support. This includes power protection, precision air conditioning and a way to monitor equipment, even from a remote location. Two essential elements for any power system are surge protectors and Uninterruptible Power Sources (UPSs). Systems must also be able to accommodate equipment that requires an AC and a DC power source.

To protect against fast power-system failures, such as circuit breaker trips or a power system fault, either dual input load equipment or very fast transfer switches need to be applied between two independent power sources to eliminate any common failures and provide redundancy.

We also reviewed preventative service and maintenance steps providers can take to further ensure reliability.

Congratulations! You have completed this tutorial.

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