I would guess that Russia has several large grids as we do here in America so that facilities in other areas can cover the shortages.
At the least, this is the time of year to have these kinds of problems, but with so many lives lost that doesn't make a difference and my heart goes
out those affected.
Looking from here - and 34 years in the high voltage power business - it looks what may have happened is:
An error in operating may have blown out a penstock.
One of the basics in operating a hydro station is that penstocks have to be shut down for maintenance and other reasons.
Penstocks are shut down by taking a particular unit fed by that penstock, closing the uphill valve, opening siphons and letting the penstock drain
before shutting the downhill valve.
If a downhill penstock valve is closed in an overly abrupt manner with the uphilll valve open the large column of water will slam the lower valve and
that usually results in the penstock blowing out and possible lower valve damage.
Aside from a particular generating unit failing which could have initially caused the problem the resultant flooding will many times take out
If there is sufficient online capacity on the grid and depending on how big the grid is, there may be nothing more than a good "bump" (voltage drop
and frequency decay for a short period which is measured in HZ, but noticeable at the customer level.
If grid capacity is down or on the edge, the voltage and frequency problems will be worse and a wider area affected.
This looks to be the case here.
Depending on what happened, the hydro plant is probably looking at a minimum of six months to a year before all three units are back on line.
(visit the link for the full news article)
[edit on 17/8/2009 by Desert Dawg]