Wanderer wrote in message . ..
On 10 Sep 2003 15:31:14 -0700, robsignals wrote:

Wanderer wrote in message . ..

snip

On any interconnected system, the National Grid being a prime example,
events are by definition related.

Bad choice of words on your part, I think.How can a lightning strike in
the west country and a 3rd party cable damage that happened to occur at
more or less the same time in the west midland be related? No, that may
never have happened, but I give it as an example of the flaw in your
argument.

If you're talking about the 400kV Supergrid you'd be surprised how
small it is in terms of connection points especially away from big
cities, may only be 2 or 3 nodes between 'the west country' and 'the
west midlands'. As power is always flowing south from the the midlands
a trip in the SW will certainly affect them. As a general point we're
both right to a degree, some effects may be very minor but they do
exist.

This incident was caused by a
classic very simple installation 'cock-up' made 2 years ago and not
discovered or exposed since; system design, configuration and incident
response were correct and supplies would have been securely maintained
otherwise.

Not true. Somewhere between design, configuration and commisioning a
current multiplier was wrongly set, and was not picked up by testing
procedures that should have picked it up.

The multiplier was correct but the relay was wrongly rated though the
multiplier could have been altered to put it right. The system was
designed correctly but was wrongly set-up, it's very unfourtunate it
didn't show in a way that caused little effect.

Paragraph 177 in the report is quite explicit about the procedures used
to commission the protection. I would not fault them as written.
Certainly the responsibility for returning a circuit to commision in
good and proper order rests *exclusively* with the guys carrying out the
work.

Or in other words management have covered themselves, theory is one
thing and practice another. Competent engineers fell into a trap that
management could and should have prevented, as far as the public is
concerned NG fouled-up and the buck stops at the Chief Executive...

Lessons have been, painfully, learnt and the relay error is not likely
to happen again. All 45,000 are being checked (none found after
9,000). I would say the system is now secure

I don't share your confidence. The report paints a picture of a calm and
ordered working environment that almost certainly did exist two or three
decades ago. I suspect those working for NGT might have some difficulty
in recognising this environment today.

I don't think the authors would win the Booker prize, they can only be
describing the current (ouch!) situation.

[EDF] should have reconnected LT in a couple of mins at most. I get the
impression there was only one engineer in their Control who didn't
know what hit him...

Unlikely if they operate a centralised control system. But.....

Outside maintenance hours as this was I doubt there's any switching of
their system...