WPD


all the new system in, and it coming back up. It was very rapid, if it went well.”


Analogue versus DMR Despite the emergence of DMR trunking technology, Western Power decided against it for its new Midlands network. T is was mainly because the Xfi n analogue system in the South West and Wales has performed well, and is known and trusted. But Kevan also has some reservations about DMR trunking.


“I still think the market is a little bit imma-


ture in that area for us to take that additional leap”, he says. “T e technology we’ve got isn’t old, anyway. For us, it’s four years old – it may have been a bit longer in the making from Andy’s point of view, but we’re more than happy with what it does. “We discussed whether we needed full du-


plex so that people can talk at the same time, like they do on mobile. It helps if you are talking to a customer on their own telephone


Xfi n trunked radio technology explained F


or its PMR network, Western Power has selected Simoco’s Xfi n trunked radio tech-


nology. A feature of this product family is that computing resources are distributed around the whole network in local blade servers, and no central hierarchy is needed. “It all talks over an ethernet backbone, which Surf Telecom supply”, explains Andy Grimmett of Simoco. “It’s a fully meshed, distributed architecture. So there are no single points of failure; there is no cost of switches; all of the spares are re- duced, so instead of having spares of all these different cards in the system, the only unit is a blade. That’s it. “With a switch-based system, you would


get to a point where you add that next site and you have to put in another switch somewhere. There’s none of that. It’s just like adding a computer to an ethernet network – you don’t need to add anything else.” With only one product to understand, Xfi n


was an attractive choice for Surf Telecoms, which wanted its own teams to handle all the maintenance. The Xfi n concept was born in 2005, a time


when most other two-way radio manufactur- ers were pursuing plans for digital products. “We took, I suppose, a risky stance of saying we are going to reinvest in Xfi n technology because we saw MPT 1327 markets being the next 10 years still”, Andy says. “We already had an MPT 1327 trunked


product line, but it was coming to the end of its life because it was suffering obsolescence and it was at the time the RoHS [Return of Hazardous Substances] Directive had come in – the reduced lead. And we looked at our existing design and we would have had to redesign about 30 different PCBs in the system just to keep the old technology going. And it wasn’t fi nancially viable. “That was when we took a step back and


we analysed our own architecture. And we said, why do we need this switch? What does it do for us? And can we start to use comput- ing technology – like distributed architectures


18


Andy Grimmett, chief technologist at Team Simoco, based in Derby


and meshed networks? And the answer to that came with ethernet. “It took about a year to realize the product,


and before we engaged with Western Power, we had already put in a number of smaller systems – a lot of single site stuff. We’ve been very successful with the UK dealer and partner market, selling through them.... But it was a leap of faith for Western Power. The biggest network we’d put in prior to Kevan was an oil pipeline in Kazakhstan, which was 19 sites – and it’s a big leap to go from 19 sites to 103. “Kevan had the vision to see that, yes, it


did work. Western Power did a lot of ‘due diligence’ work to get under the skin of the technology, to fi nd out that what we were saying was in fact true. And within the Surf Telecoms team, they’ve got people who have been around MPT 1327 networks as long as some of the people in our business, who’ve been there 40 years. So there’s expertise in the customer side as well as on the supplier. There was no way we were going to hoodwink them into anything that wasn’t true! “The biggest system we have is still the


Western Power one. We are currently putting one in for Scottish and Southern Electric which is around the same size, and they are also taking the system in the South as well, which will make it a bigger network than Western Power’s – until the Central region comes on.”


– but between the control room and the indi- viduals that are out in the fi eld, or between the individuals on diff erent mobiles in vehicles, it makes no diff erence if you have to wait until the other guy has spoken before you talk. So we’ll stick with the half-duplex that we’ve got now.”


Staying connected With the new radio system, Kevan believes he will be able to provide the company’s fi eld technicians with a communications tool which better meets their needs. “In the Midlands eve- rybody seems to have a mobile phone, from the apprentice and the janitor right up through to the top bod”, he observes. “It’s not like that in Western Power: the guys in the fi eld don’t nec- essarily have a mobile phone issued to them. Some use their own, which is fair enough. “We try and use the PMR system to comple-


ment, supplement (whatever words you want to use) the mobile phone network, because it is obvious that people are going to use their mo- bile phone to call into control.” However, the PMR system is expected to of-


fer much higher reliability than mobile phones typically provide. “Recently, when the Vodafone network went


down completely from Basingstoke – I think there was some major vandalism or theft of equipment – the whole of the South West and Wales was down. But our guys were able to still function because they had their PMR. “It’s a bit dramatic, but essentially we are an-


other essential service, aren’t we? We are like an emergency service in some ways, so if our guys can’t get out in a blizzard to fi x something, then communities go without their electricity.” Kevan points out that the resilience of some


mobile phone networks is less than 20 min- utes on battery backup. One mobile phone operator, he adds, actually scaled down its battery backup to just 10 minutes after not- ing that the average electricity outage is only 74 seconds. “We are looking at a 72-hours ‘black start’


scenario, where the whole country may go black for three days. We’re going the other way – in fact, some of our radio sites now have got 128 hours’ backup, because one of our custom- ers specifi cally wants black start plus blue-light capability.”


A smarter grid One of the areas Kevan wants to concentrate more on in the future is how the trunked sys- tem interfaces with the company’s Scada re- mote monitoring and control equipment. “We want to use the VHF PMR system to


provide some alternatives for communications out to our outlying plant”, he says. “We use various UHF channels at the moment – some


LAND mobile September 2012


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