The Lovely Weather

RTNI

With transmission lines you can switch in capacitors and inductors to raise or suppress the line voltage. Also if the load changes (eg transmission line taken out) then the frequency of supply will alter from the nominal 50Hz. If it goes too low, (when there is not enough supply to meet the demand) then the grid is in danger of having a blackout. Baring in mind that the power stations have to send their forecasts to the SONI (system operator NI - the place near Lagan College that Caz mentioned) around 12 - 24 hrs in advance it can be very difficult when things start breaking!

If would be very rare for the power stations to gun their generators at full 100% capacity - generally they would run them at about 75 - 80% capacity each so that they have what's called "spinning reserve" that is, extra energy that can be obtained quickly by allowing more steam into the turbines while they start up some other plant to cope.

Havinf the DC internocnnector to Scotland and ROI means that the size of the "grid" is much larger and that small changes in NI can be compensated for by the other ROI and GB grids so we shouldn't notice too much - but with 70,000 homes off the air the other day that was a nightmare I'm sure for the operators and power station engineers!

caz2703

I knew someone who had more knowledge would come along and explain things properly! This is why I work in IT and not somewhere like NIE.

RTNI

Don't take that as gospel now, just what I studied in my engineering degree! Might be a bit rusty but I think that's the basic operation of it.

caz2703

I'm surprised you know of SONI as very few people over here realise that we control our own grid. Hearing terms like spinning reserve makes me think I should have listened more when things were being explained to me. Ever heard of SEMO - no Google'ing?

Don't suppose you can confirm my reservoir theory as well and it was posted yesterday so not an April Fools!

Belfast_Mum_2

Does anyone know if Bushmills has electricity? Thinking about heading up tomorrow for week but heard on Radio Ulster that supply was down around Ballymoney/Coleraine.

RTNI

caz2703 wrote: »

I'm surprised you know of SONI as very few people over here realise that we control our own grid. Hearing terms like spinning reserve makes me think I should have listened more when things were being explained to me. Ever heard of SEMO - no Google'ing?

Don't suppose you can confirm my reservoir theory as well and it was posted yesterday so not an April Fools!

I have not googled it (honest!), but would guess Single Electricity Market Operation? As for the reservoir idea, I suppose it would work - but do we have any Hydo-electric generation? I would just imagine that if there was too much voltage the frequency would increase and then automatic breakers would open to remove excess generation from the grid on the power station side. This would take a matter of seconds from what I know.

I remember that the power consumption of pumps and fans (any induction machine) is related to frequency - as frequency increases the power consumption of them increases as the rotate faster.

Spinning reserve is important as even the fastest plant to start up (open cycle gas turbines, or closed cycle gas turbines, cant remember which it is) take around 5 to 8 mins to strt from scratch to generate electricity, and that is obviously too long to wait if a major generator is taken out by something. At least if that happens, then the automatic governor valves open on the remaining generators and increase the amount of steam entering to take advantage of the spinning reserve. The OCGT or CCGT's are very very expensive to run compared to coal or oil based plant, so that's why they are really used as in interim measure while other more cost effective plant is brought on-line. It can take up to 8 hours for a coal boiler to be at a high enough temperature to function and produce steam, hence why the forecasts for the power stations need to be received a day or so in advance.

Suppose that leads onto the economics of electricity operation such as spot and market price per unit etc....

quintwins

talk about global warming, it was snowing yesterday and now it's lovely today, i have washing out and my windows open lol

caz2703

Well Robin, I hope you got a 1st in your degree with that knowledge. I also hope you're working in somewhere like SONI or NIE with what you know.

SEMO - Single Electricity Market Operator. A joint venture between EirGrid (RoI) and SONI (now owned by EirGrid) aimed at linking the market North & South and thus introducing competition and reducing the cost for the consumer. I know it's April 1st but that is what's meant to happen. Can't say I've noticed a reduction in my leccy bill

RTNI

Oh cool I didn't know when that came into effect. Hopefully it will make a reduction, but can't see it!!

Unfortunately I don't work for NIE or SONI - not sure i would want to be at the moment or for the next week or so! lol!

caz2703

Err SEMO has been up and running for over 2 years now! Noticed any benefits yet?

Quote:

At midnight on Thursday, 1 November 2007, the Single Electricity Market
successfully moved into live operation, launching a new era for the
wholesale trading of electricity.