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Showing posts with label electrickery. Show all posts
Showing posts with label electrickery. Show all posts

Sunday, 4 August 2013

Power bollocks

I was just reading Christopher Booker’s  article this morning in the Telegraph this morning.

We could soon be paying billions for this wind back-up

In it he explains the Bizarre thinking that to stop the lights going out the government is going to use all the backup diesel generators that exist in hospitals and other places that need to have an emergency supply of electricity.

The answer National Grid has come up with, only made possible by the latest computer technology and “cloud software”, is to hook up thousands of diesel generators, remotely controlled by the grid, to provide almost instantly available back-up for when the wind drops.

Personally speaking as an engineer that has spent most of his working life working with diesel generators, I think it is a disaster waiting to happen.

I don’t see how it could work.

1. All types of generators have a different “Characteristic”. Steam turbine generators, gas turbine generators, and diesel generators all respond differently to changes in load. All these generators have to supply power within a narrow frequency band either side of the grid frequency of 50 Hz. Usually within a maximum of + or - 3 Hz. How is your local hospital’s 1 Mw diesel set going to respond to the response of  a 2 Gw gas turbine. The danger is that unless the load sharing is precise (involving electronic governors these days), you could end up with a gas turbine actually “motoring” a diesel generator. In other words the DG is being driven electrically against it’s will. NOT A GOOD THING. It usually ends up with large lumps of diesel engine deciding to spread it’s self into it’s component parts. (I know. I walked past such a generator 5 seconds before it did it.). That’s your hospital fucked in the middle of winter when the wind turbines are not working.

2. All emergency generators are just that. They are arranged that if the mains power fails they are an autonomous entity.Just there to  supply the Hospital, public building, brothel, etc. Usually they are arranged that if the main supply circuit breaker drops out due to mains failure, the standby diesel generator will start and then close it’s emergency breaker onto the needed system.. QED. For safety reasons, the mains supply breaker and the emergency supply breaker are interlocked so that neither can be closed simultaneously. I’d love to know how they are going to load share between their patients and the grid?

3. As above. Does the hospital, if the rules change on electrical safety, save it’s patients or sell it’s Kws to the grid?

I feel that this is a cynical ploy by a government that has lost the plot on energy production to try and calm the average citizen, that the lights will remain on.

I have candles.

Sunday, 16 September 2012

Electrickery

I’ve just got back from the eldest daughter’s house (Again) and on arriving there I was tasked with fitting a couple of dimmer switches. A simple task not really requiring much brainpower. Isolate the circuit, unwire the existing switch, replace with the dimmer switch, and reinstate the circuit. Job done.

Of course some would have it that I should, at vast expense have called in a qualified electrician. They would be wrong in their thinking. I actually hold a high voltage certificate that allows me to work with voltages over 1,000 volts. I had to obtain this in order to enter spaces and work upon machinery operating at 6.6 kV. (6,600V for the non technically minded).

The other qualification I had was that I’d worked on a class of ship that was not complemented for an Electrical Officer. I became that man. Alongside my other duties of looking after the main diesel generators, and the refrigeration plant. Being somewhat suspicious of a killing energy that can’t be seen I took extreme care to make sure that I followed the rules of “Isolate, test, test again, and work on it”. (Once I disobeyed my rules and touched a live circuit with 440V. Never again. It threw me six feet and I was probably unconscious for a minute or two).

Now to the crux of this post. Familiarity, adverse conditions, and sheer bad luck come into play. My outfit started to man the ships with electrical officers. Of course, us amateur electricians were told by these electrical officers that we had done a piss poor job. This pissed off most of us that had done the job, whilst holding down at least two other jobs (See above).

There was a problem with the control panel for the refrigeration rooms. The only way of sorting this out was for the electrical officer to switch of the power, open the door, and fiddle the door interlock controlling the main power switch to reinstate the power to enable fault finding to begin.

The sad part was that the ship  was rolling, the deck was oily, and oh dear, the lecky pitched headfast into the cubicle, striking his head on the 440V bus bars. And sadly that was the end of him..

Now you may say that I’m being disrespectful of the dead with the next part of the post.

After the body was removed from the vicinity it was realised that the body would have to be preserved until a post mortem could be carried out. That was the excuse for all the engineers to collectively define the initial problem and rectify it. The body needs to be preserved in a cool room. (Bye the way, never store the body in the deep freeze. Coroners will crucify you for that).

However I heard through the grapevine that the real cause for concern was that one of the refrigeration chambers was exceeding it’s set temperature. This was the “Beer Room”. Engineers can’t abide warm beer.

OK I’ll rot in hell if you wish. But I’ve heard this from multiple sources that I trust.

Moral of the story: You might be the expert, but circumstances can kick you up the backside without warning.