Hybrid power for remote communications networks – Part One

By Peter Spiteri*

Modern mining facilities are faced with the dilemma of how to power a variety of telecommunications and networking equipment as reliably and economically as possible.
However, with the convergence of information technology and telecommunications networks, equipment input power requirements are no longer standardised around -48VDC. Alternative approaches have been devised to power modern telecommunications facilities having both AC and DC-powered equipment.
Its useful to consider the advantages and disadvantages of the various design approaches along with application-specific guidelines considered best-practice for Australia’s mining industries.

48VDC – The Traditional Standard
Since it first came into being almost two centuries ago, the electronic media for point-to-point communications remain the undisputed lifeline of most businesses.
The basic anatomy of telecommunications, as the telephony system came to be called, has changed significantly. In most cases, telecommunications systems transmit data by wire, radio, or fibre. What has changed most dramatically is the importance, the type, and amount of data transmitted.
The growth and complexity of telecom applications has sharply increased, with no end in sight. The interruption of voice communication can be significant enough, but add in the huge masses of data created by millions of computers tied together into global networks, and the impact of downtime spins from inconvenient to unconscionable.
Reliable, clean and continuous power is at the heart of continuous telecommunications operations. Traditional telephony applications – from central office exchanges to PBX networks – have standardised around a –48VDC source. There are many reasons for this. First, its negative polarity reduces corrosion problems with underground cables and conduits. The low voltage made it easy to implement, as well.
Systems using less than 72V generally did not require licensed electricians nor were they governed by the NEC. As opposed to commercial AC, DC power is the “standard” for carrying voice signals. DC is considered more reliable because it is more easily stored than AC power.

The Communications Convergence
Two factors have combined to change the power protection needs of telecommunications applications forever.
One, as mentioned, the critical nature of the applications has increased. Certain operations simply cannot be shut down. Two, the convergence of information technology and telecommunications networks has created a whole new “communications” environment, and therefore a new set of challenges. Instead of supporting telephony services across a large geographic area, that same local telephone network may now provide access to the Internet. Similarly, telephone services can now be provided through cable.
Modern telecommunications facilities are faced with a dilemma: powering this new variety of equipment as reliably and economically as possible, protecting against threats to these convergent systems that are many and diverse.
The birth of co-location facilities is an example of the growing need for both AC and DC power in a secure, configured space.

Identifying the threats
The first concern of virtually any facilities manager is the ability to ride through power outages. Another factor is proper cooling. When computer systems left the security of the “glass house” computer room, they also left behind the environmental protection that was so vital to their proper operation.
Sensitive telecommunications equipment is vulnerable to environmental threats as well. Excessive heat can damage or impair the operation of critical systems and peripherals. Constant uptime of networks that include both computer and telecommunications cannot be achieved unless environmental protection considerations are factored into the equation. Simply put, sensitive computer and telecommunications equipment works better and is more reliable in an optimal environment. This can be far different from the “comfort” air-conditioning experienced by people. It doesn’t necessarily require a glass house, but it does often demand an environmental protection system that delivers round-the-clock performance.

* Peter Spiteri joined Emerson Network Power in 2003, bringing with him over 20 years of experience in marketing management, IT and engineering. He started his career as a software engineer with Honeywell in Boston, designing the EFTPOS network for Australia and New Zealand. He then held various product marketing and channel development roles for 3COM, Cisco, Tech Pacific and Nortel.

To read the final part of this report see next weeks AJM newswire.