Wednesday, August 4, 2010

National Engineering Week - Electrical

We're half way through National Engineering Week and now we're starting to get to the stuff that I actually know something about. Only starting to mind you, the chasm between electrical and microwave/photonics engineering is just as big as between electrical and civil engineering.

There's also a distinction that I'd like to make between electrical and electronics. Electrical is all about electricity - power generation and transmission from power stations to users are the big ones, I'll also lump HVAC (which stands for Heating, Ventilation and Air Conditioning) in here too, since they usually use 240V AC (i.e. mains power, the stuff running around in the walls of your house).

Power generation is obviously pretty important, especially in western society. You wouldn't be reading this blog, or catching an electric train without it.

The transmission side of things is just as important though. The big thing with transmission is the concept of loss. Crudely simplified, the power station puts a signal onto the line at their end, but it's smaller when it finally gets to your end. The difference is what we call loss, and it's power that in one way or another is wasted. Now for you to be able to use the energy that you want, the power station has to put extra on at their end to cover the loss in the middle. The more loss, the more they have to do extra, and the more it costs everyone - especially you and me!

Because of this loss, a lot of research is going on into technologies like high temperature superconductors. A superconductor has much less loss than the cables we use today, which would be much better for the power companies. But there's a problem. For a while scientists have been able to make superconductors at low temperature. Really low temperature. Like a couple of hundred degrees below zero temperature. Which is not very practical if you want to get electricity from Tarong to Brisbane. The aim of HTS research is to find a compound that first of all works at reasonable temperatures (say, anything about zero degrees C) and second of all can be manufactured in the quantities needed to replace the current grid.

So what's spectactular about electrical engineering? Aside from actually generating power and reliably hooking up multiple power stations to users who are constantly turning things on and off, but without having the whole system fall over? Well, one example would be the solar power towers in Spain. They were also featured in Richard Hammonds Engineering Connections, which I mentioned the other day.

What happens when things go wrong in electrical engineering? Well, if you happened to be in a small town in the Ukraine on 26 April 1986, you might not have been very happy with the local power company. That's when the Chernobyl disaster happened. In all fairness to the electrical guys, Chernobyl was a result of many, many things going wrong, but since it's a power plant, it fits with today's theme. Another example - the power grid in the north east US can be a bit unreliable, as massive blackouts in 1965 and 2003 showed.

Tomorrow, we'll find out what makes electronics distinct from electrical engineering.

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