On 2009-09-01, Cydrome Leader wrote:
Ignoramus25738 wrote:
On 2009-08-31, Cydrome Leader wrote:
damn shame. terrible tragedy.

the wiki article said the one turbine blowing up caused a electric shutdown
which resulted in the other turbines that were on line to overspeed and blow
up too.
amazing.

clever design.

An interesting story, all in all. Allows for good after the fact
thinking.

How would one stop a hydroturbine, if its electric load disappeared?
I would suppose that it would overspeed in seconds, so anything to
stop a turbine, would need to be done quickly and automatically.

Open some sort of a sluice in the line that feeds turbine with water,
to divert and dump the water elsewhere, would seem like the only
possible solution.

The amount of available options would depend on how quickly the water
would overspeed the turbine. Such a calculation should be possible
based on available data, such as water column height, turbine mass,
and turbine radius.

It sounds like you're ahead of the designers there. I'm not even joking
this time either.the pow

There are many ****ups, that are very obvious in retrospect, but not
necessarily before the fact. Which is not to suggest that the power
station was well designed.

A very interesting accident is a shutdown of a large portion of
electric grid in northeastern US for several days. Some say now that
hackers were responsible, while others cite cascading troubles from
not so well thought out control systems.

http://en.wikipedia.org/wiki/Northeast_Blackout_of_2003

Another one is the famous AT&T telephone shutdown.

http://www.faqs.org/abstracts/Busine...main-on-h.html

By the way, my dad used to design earthen dams (gravity dams) for
hydroelectric power station. Many interesting issues there, such as
interaction with permafrost cold weather, and seepage. Some of the
ones in the far north, used cooling to keep the cores frozen
permanently.

i