SNITTERFIELD WI

FEBRUARY 2012 REPORT

Our speaker this month was James Watson, an engineer who spoke about the National Grid, by whom he was employed. He is the son in law of W.I. member, Jan Horsnell. It was an open meeting and several men availed themselves of the opportunity to listen to an expert on the subject.

James explained that his responsibility was the transmission of electricity from the power sources, such as the power stations and the new energy sources, such as wind farms, to the 319 sub stations run by the six large private companies, and which are the distributors of the electricity to the whole country. The map of the National Grid shows clusters of these sub stations in areas of large conurbations, and industry, particularly in Wales, London, the West Midlands, the North West and the North East.

In Victorian times, arc lights, invented by Humphrey Davy and his assistant, Michael Faraday, replaced the candle power and gas lighting of earlier times, providing a much brighter source of light. James demonstrated how the arc lights worked on a model, with the electric current sparking across a narrow air gap to produce a very bright light.

The electricity from the sub stations is carried to cables by the tall, strong frames of the transmission towers - not pylons - which are visible all over the country. The accompanying tall, pointed structures act as lightening conductors. It would be expensive to conceal the cables underground. The cables that are used these days are made of aluminium, which is cheaper, lighter and use less space than the original copper cables. He circulated samples.

James showed us the graphs of the peaks and troughs of electricity distribution, which have to be balanced over 24 hours, and it was fascinating to note that these peaks coincided with the TV adverts and football half times, when we al rush to turn on the kettles! Special events such as the Royal Wedding have to be planned in advance, as increases have to be switched 30 minutes ahead.

The National Grid has been very involved, of course, with the building of the Olympic Park and here 57 transmission towers have had to be removed, and all the cables have been put into miles of tunnels underground.

It was agreed by everyone that it had been a most interesting talk.