Balancing power options is no easy task
The cable TV industry has come a long way in the last decade or so, in a lot of different ways. With the introduction of two-way systems for high-speed data and interactive television, and now with the advent of lifeline telephony services, network reliability and the powering systems that make it all possible have become absolutely vital.
The industry, says Eric Wentz, vice president of marketing for Alpha Technologies, has turned a crucial corner. "Let's all be honest with ourselves," says Wentz. "The networks that provide today's telecommunication services are much more sophisticated and complex than the systems of old. Every element of the networks has increased in sophistication and complexity. Along with that has come the increased need for overall network reliability. It's not your father's old cable system anymore."Powering conundrum, part one
With the launch of new services, operators are having to decide in relatively quick order the kind of powering scheme they want to deploy to support these 24/7 services. While deciding whether to pursue a distributed or centralized power architecture, operators are also trying to deal with boosting per-subscriber power capacity and extending the run times of backup powering systems.
Balancing the speed-to-market forces from the outside, operators are finding it's no easy task or a clear-cut decision on which course to pursue.
"The thing we keep hearing over and over," says Rick Marcotte, vice president/general manager at Invensys Energy Systems, North America, "is that operators are having deployment problems with centralized powering solutions. They're running into a vast number of problems that they hadn't anticipated. They're running into neighbors who don't want big, ugly, noisy boxes near their houses. So, there are site acquisition issues. There are neighborhood pushback issues. There are noise and heat generation issues. And there's cost."
Cox Communications has been one of the most aggressive operators when it comes to telephony. And it's that power-intensive service that dictates a good portion of its decision-making process when it comes to power and standby backup systems, says Dick Mueller, vice president of operations engineering for Cox.
"We have defined the powering requirements for our advanced networks," says Mueller. "Fundamentally, we're building what we call 90-volt NRUs, or network reliability units, that are generator backed up power supplies. That way, we're not dependent on the power company, which can be one of the more unreliable aspects of our network.
"In the networks where we're going to offer telephony, we have these NRUs installed in a million or so homes passed. We have two configurations. We have a centralized power node which is fundamentally one large generator backed up unit for the entire fiber node. On average, our fiber nodes are pushing 700 homes."
Cox has also developed a distributed power approach that includes two-and-a-half or three distributed power supplies, on average, in a node. That means each supply covers about 200 homes passed.
Mueller says he doesn't believe Cox will opt for one powering scheme over the other. But, he says, telephone penetration is a key factor when deciding which scheme will be used, and where.
"We're going to mix, there's no doubt about that," states Mueller. "We started off as all-centralized, where you design a power grid for telephony, and power all the boxes on the sides of the home from our network. We have to get the reliability we need.
"When you do that calculation, the power draw on the box on the side of the home varies, whether it's off hook, on hook or ringing. So the math is very complicated. But when you do a centralized design, you have to assume a penetration rate and you have design specifications to meet that minimum penetration rate. We started off centralized and our minimum penetration rate for design purposes for power was 20 percent.
"Very quickly into our telephony deployment, we had nodes exceeding 20 percent penetration. That's what led us to the distributed approach, which gets us a significantly higher penetration. We can go as high as 100 percent based on where the power supply is," Mueller says.Powering conundrum, part two
Operators are demanding two things when it comes to powering and backup power solutions, notes Wentz. "Our customers are saying, `We need more power than what we've had before. And we need longer run times than we've had before.'"
This demand for increased power-per-subscriber, says Wentz, represents a crucial change in the industry. "Typically, a rule of thumb when it came to power capacity per subscriber was in the 2- to 3-watt per subscriber range," says Wentz. "We're now seeing (a rose to) the 5- to 6-watt per subscriber range. This doubling of power capacity is a fundamental and very, very significant shift in the industry."
As a result, Wentz says he also sees operators shifting from a distributed architecture to a centralized approach. At the same time, he notes operators are trying to address the problem of extending the run times of power back up systems.
"Typically, the equivalent standard for run time," says Wentz, "was somewhere in the two- to three-hour range. We're seeing that move out anywhere from 8 to 10 hours run time.
"Depending upon the particular power requirements, we're finding some customers are sourcing larger capacity power enclosures. So, instead of single string of three batteries, some customers are electing to put in two strings of three batteries each that would end up somewhere in the neighborhood of 4 to 5 hours backup time."Home sweet home?
Another backup powering solution that's still getting a lot of attention, despite its obvious pitfalls, is home-based powering. For the operator that's looking to get to market quick, it may offer an interim fix for a very difficult problem that has no easy solution, says Wentz.
"We're seeing customers opting for the (home backup powering) option, at least in the interim or on a temporary basis, as means of power protection at the subscriber home. It is a much smaller installation with smaller power output. It's less sophisticated.
"They may feature a run time anywhere from 6 to 10 hours via a very small battery system. The upside, it's a fairly straightforward installation where the cost of the unit is directly applied on a per-subscriber basis. You don't have to put up the capital investment for a network powering system that could support an entire neighborhood. You end up with a much smaller cost, on a per subscriber cost.
"The downside is that because it's on the inside of the subscriber's home, typically the garage, it calls into question access, maintenance, the responsibility of reliability of the network, i.e., does it still belong to the service provider or the customer. In addition, there is the issue of subscriber interference with the product.
"That means this unit is mounted on inside of the wall in the garage and has to access a utility outlet in the garage. To give you a grassroots example of what's happening, we have subscribers who are unplugging their battery backup unit for their telephony service to plug in their ShopVac. And when they do that, it flashes an alarm back at the headend and that necessitates a truck roll."
Despite the danger of increased truck rolls, home powering still has its attractions in the United States and Canada, according to officials at American Broadband, a Boston-based overbuilder/broadband service provider.
"The neatest thing we've seen recently," says Bruce Jones, vice president of product strategy at American Broadband, "was in Montreal where Videotron just went commercial with a 50,000 line VoIP service. They are actually using a "dumb" battery in the home. It's a $7, lead-acid battery.
"All the intelligence to manage it is in the modem that's doing both the computer and the telephone inside the house. The unit can monitor battery status and signal if it doesn't look good. They can also proactively monitor battery status. It is a very nice, cost effective solution."
As the company searches for a powering/back up solution, says Al Kuolas, CTO/vice president of engineering at American Broadband, it's a balancing act that has no easy answer.
"The problem that we're facing is that if you want to do about eight hours worth of standby, you need a pretty big box. In some cases, you can still do that. If you want to do anything more than that, now you're really in trouble because you need a generator. The generator needs fuel and there are all sorts of environmental issues. Depending on the community you're talking to, some are more open to that than others. That makes it very difficult for us to have a consistent, one-plan-covers-the-whole-network approach unless we go with the home powering solution.
"The disadvantage of going with home powering is that if you put in a battery today, it may give you 8 to 10 hours with these new modems that draw less current. But that means five years from now you're going to be out there doing an awful lot of service calls replacing batteries.
"The argument for that is that, on average, you're doing 20 to 25 percent service calls on an annual basis anyway. So, over the course of about four or five years, you're going to visit virtually every home. So, when you're there, you take a look and check it. And if it needs replacement, you do it then. Maybe that's not a bad approach and that's certainly the approach that the people up at Videotron have taken.
"We're buying into it because it's the way that makes the most sense for us at this point. The more we've thought this thing through, we've found nothing is perfect and everything is a compromise. But, from that perspective, we're prepared to compromise by going to the home powering solution."Fly by solution?
One of the most intriguing powering solutions to come along in recent years appears to have finally come out of its beta-trial cocoon phase. By all indications, flywheel technology may soon be coming to a system near you, says Bill Bauer, president and CEO of WinDBreak Cable, a small cable system in Gering, Neb., which field tested a flywheel system from Beacon Power Corp.
"The first two production units are up and running and have been since the first part of October," says Bauer. "They went in for Verizon. The next two are going to Cox in San Diego. Those shipped, I think, last week (the end of October). And then the next one is coming to me.
"We're going to take out the prototype unit we've got up and running and replace it with a production unit. And the push is to have it in before the Western Show."
Flywheels serve as electromechanical batteries that store and release energy from a high-speed rotating flywheel, which is positioned inside a steel enclosure. The flywheel itself is made up of a high-strength fiber composite rim that spins anywhere from 20,000 rpm to 30,000 rpm to store 2 kilowatt hours of useable energy.
The composite rim rides on a magnetic bearing inside a vacuum container and spins almost indefinitely once the power is shut off. Energy is then drawn from the motor.
Bauer says both he and the company learned a great deal during the field trials. Over the past few years, the company has redesigned its electronics unit, replaced mechanical bearings with magnetic bearings, completely redesigned the housing and supportive mechanisms, and upgraded the composite materials used.
According to Bauer, flywheel technology fills a very important role for over-stretched operators, especially because the flywheels are designed to require zero maintenance for 20 years. "The reality is that we know we needed to backup our systems. But the first thing that doesn't get done because we have so much to do, is checking whether the batteries are working or not.
"The whole goal was to replace the batteries with something that we didn't have to take care of because we're aren't taking care of the stuff that we've got now. It's a good, solid direct replacement for the batteries we're using."
What's the downside at this point? To the surprise of no one, it's the price, says Bauer. It's currently pegged at about $15,000 per unit. "My biggest struggle is price. But, gee whiz, that's no surprise with any operator and I'm no different than any other operator out there. But, we definitely feel that if we, as operators, start purchasing them, that price will drop in half without much trouble.
"And being an operator, you can bet I'm going to wring out every bit of price that I possibly can to make these things do what I want them to do. I want to put them in every power supply we've got out there."Bringing it upfront
Whether it's high-tech batteries, whispering generators or composite rims spinning magnetically in some steel-encased vacuum, powering/standby solutions have finally taken their rightful place in the broadband planning arena, says Invensys' Marcotte. As a result, the industry has gone through a major shift.
Marcotte says power was often overlooked by system designers in the past. Slowly, that's changing. "We're seeing a lot more upfront planning on the power side of things. Quite frankly, that's being driven by one thing, and one thing only.
"If you're going to be in the broadband game—moving data, doing transactions, doing PPV/VOD—you really need what I call telco-grade power.
"People are absolutely used to the fact that when the power goes out, the phone still works. So whether it's an HFC network or a telephony network, if you have a power outage and the phone or data line doesn't work, you're in trouble.
"I think that reality has brought power to the forefront. So the reliability of the system forces the thinking about powering up at the front end, and that has been quite a change in the culture of the industry."