On Mon, 24 Jan 2005 21:43:36 +0000, John Rumm wrote:

Wanderer wrote:

As far as you, the domestic customer is concerned, it happens at primary
substations, (33kv/11kv) Current and voltage transformers are connected to
relays that detect the load being drawn on the 11kv network and either step
or step down the 11kv voltage. The transformers have multiple taps that can
be changed on load.

When a line is lightly loaded, the notional supply voltage close to the
prmary sub might be about 11,200, to say 10,800 right at the end of the
circuit. As the load goes up, the notional voltage increases to allow for
voltage drop in the circuit.

Interesting stuff...

So is this where they would tinker with the voltage if they wanted to
shed some load, or would that be done further back in the network?

Yup, stage 1 and stage 2 load shedding (3% and 6% voltage reduction) is
done these days by telecontrol from central control rooms, by making the
system transformers lower the tapping. It happens - or used to - much more
frequently than you might think, especially during winter months.

Stage 3, rota disconnections - 3 hours off 3 hours on - is also largely
done by telecontrol, something we haven't had for some years now.


--
the dot wanderer at tesco dot net