Underground monitoring system

Paul Boughton

Dragoncam is a special underground monitoring system which checks the inside of cable ducts for ridges and damage. This innovation could save developers and Network Operators and Developers (DNOs) thousands of pounds by removing the risk of having to dig up damaged cable.

Dragoncam illuminates the insides of ducts or channels and records footage as it travels through the system, which can then be analysed by site managers and developers to ensure all the ducts have been laid correctly. 

The Dragoncam was designed by Dragon Infrastructure Solutions in response to challenges faced on site at Kerriers Solar Farm in Cornwall. 

DragonIS which was connecting the site was asked by the local network engineer, to prove that there were no ridges inside the 5.2 km of duct that it had just laid. 

Each section was joined together at 100 metre intervals and on occasion was up to 1.5 metres underground. When such channels are connected incorrectly, small ridges are produced. These can be as much as 12mm thick. This becomes an issue when the electricity cable inside the duct is working at its maximum capacity, because it becomes very hot. When hot it is more likely to become misshapen due to these ridges, which can result in future cable failure. This is a major issue as repairing such a cable on a job of this scale may involve a large amount of expensive excavation and of course disruption to the electricity supply.

The length of the channel at the Kerriers site meant that using an ordinary camera system to check for ridges would be very expensive. It was estimated that the cost would be over £12,000 just to live stream from inside the duct and it wouldn’t record every detail. DragonIS’ solution was to build a video camera into a tubular trolley, adding a series of spotlights and wheels, in order to produce footage from inside the duct. 

Dragoncam does not need to be attached to specialist equipment

The Dragoncam does not need to be attached to specialist equipment and is simply attached behind a duct brush – equipment used on every site - and winched throughout the entire system. Because it is set on wheels, it is able to travel freely along the channels, ensuring every join is recorded clearly. The spotlights make sure that the camera has enough light in which to capture its findings before any analysis can occur.

Stephen Branch, Civil Engineer says: “Dragoncam is ingenious. I had no reason to think that there were ridges in the channel of duct which had been laid. But with the channel being so long and deep, I just wanted reassurance. The Dragoncam gave me that - the duct was perfect. It’s a really clever piece of kit and shows just how creative and customer-focused the DragonIS team is.”

In addition to being the leading independent connections provider for large scale solar energy sites, DragonIS has worked with all of the UK's national house builders, landowners and developers on over 200 major construction projects, constructing over 300 substations and connecting over 10,000 houses and apartments to the national grid.

Dragoncam is likely to be welcomed not only by developers but also DNOs, as once a grid connection has been successfully installed it is adopted by a DNO. Should anything go wrong after the connection has been adopted, it is up to the DNO and developer to fix, potentially at high costs. Dragoncam is most likely to be used on projects with long ducts, or channels that are buried deep underground, where any repair works are going to be expensive.

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