CPS Auxilion engineers reminisce about operational successes, battery failures, consequences and near misses - highlights of careers in Power Engineering

• There was a site maintained by Damovo at Leeds City Council. The customer said that there was a strong smell of rotten eggs emanating from the communications room. A little later the same customer reported that the smell had gone away.

The initial reaction was to cancel the requested callout visit, but as the engineer was already in Leeds we decided to check anyway.

Using a portable spectrum analyser and breathing apparatus our engineer checked the environment within the equipment room. The level of Hydrogen Sulphide and acrylonitrile was sufficient to kill a human being.

Batteries taken from the site took three days to cool down.

The gas emitted by these batteries is basically the same that good old Uncle Sam used in the gas chamber.

Investigation found that the battery was less than three years old. Failure was attributed to the extremes of operating temperatures within the equipment room.

• BBC Television Centre, London - a ten thousand exchange line system that was originally powered by individual 84 amp power systems, each supporting up to 5 LIMS. We were asked to install a central power system, connecting power to each of the 120 LIMS without any disruption! That was a job and a half!

• London Underground’s Network Communication system recently underwent a major power upgrade on sixteen sites. This entailed the replacement of some 34 tons of Plante cells and 32 large transductor rectifiers. The result was the installation of dual switch mode power cabinets with sealed battery cells. The work was carried out in both traffic and engineering hours when the possibility of any disruption to service was never an option. Lose any part of the communication infrastructure and the entire tube line could be closed - it does not bear thinking about! Another job well done.

• There is always a reluctance to spend money on servicing equipment that may seem irrelevant. It’s quite possible that this is for two reasons, firstly it’s tucked away out of sight secondly it does not seem important because its considered very much a peripheral item.

The worst example of maintenance neglect I have ever witnessed was the White Hill Earth Station disaster in 1991. Whitehills is the Mercury satellite transmission site based in Oxford.

Somebody there decided that they needed a longer standby time in the event of mains failure. In order to achieve this they put two large banks of batteries in a metal container next to the main equipment building.

The initial work was conducted in the early spring; temperatures were low and the container was cool. Bring on the summer and temperatures in the seventies and eighties, an all-metal container with no ventilation - all the ingredients for thermal runaway.

And runaway it did. Strangely when it exploded it was six thirty in the evening and not at the height of the midday sun. Thankfully there was only one operative on site and I dare say he recovered fully from both the burns and the trauma in time.

The HSE report detailed an estimated temperature within the container of 130°C prior to the explosion; the batteries had got hotter and hotter until they eventually went into a runaway situation. The report also indicated that no inspections or checks had been made in the container, the facilities manager was quoted as saying “they were just batteries we had them fitted and then forgot about them!"

• The London Stock Exchange never sleeps; even outside of trading hours there are essential communication and data links that must be maintained. We undertook a major change out of the power equipment and batteries without a hitch.

• Undoubtedly the most nerve racking project that we as a company have ever been involved in was the upgrade of the power system supporting the speech platform system for the National Air Traffic Control Centre at Prestwich in Scotland. Again down time was not an option, this was without doubt the most satisfying project that we have been involved with.

• The previous projects, whilst without doubt hazardous, were conducted in environments where the working conditions were reasonably favourable. Installing fifteen power systems on mountain radio sites in the Highlands of Scotland in the middle of winter takes some beating. Admittedly these did not require live working, however the hazards were getting the equipment to site in some of the most treacherous conditions imaginable. Snow cats, landing crafts, helicopters - you name it, we’ve used it!