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W6KWF  > TECHNI   03.10.21 20:10l 54 Lines 2416 Bytes #999 (0) @ WW
BID : 09769_W1XSC
Read: GUEST
Subj: Scattergood-Olympic Line 7/7
Path: PI8DRE<PI8CDR<DB0RES<ON0AR<IW0QNL<IW2OHX<IR1UAW<I0OJJ<N6RME<W1XSC
Sent: 211003/1752z @:W1XSC.#NCA.CA.USA.NOAM [Santa Clara Co] #:9771 $:09769_W1X

12/11/89

The pipeline is now completely drained and filled with nitrogen at
atmospheric pressure. They are still in the process of opening up many
of the splices to install the collars. They originally planned on doing
14 of them but now the number is 17.

The splice where the short happened, and the cable for about 40 feet to
either side of it, has been completely replaced. Engineering prototypes
of the aluminum collars are now installed there and the whole thing is
all welded back together. They built new vaults under the street where
the new splices are. The trucks, men, and their equipment are all gone
and the roadbed has been repaved. They consider the segment where the
short happened "fixed". We'll see...

Now that they verified the assembly of a splice with the new collars in
it (to make sure they had the details right) they are going ahead with
the fab run for the 17 other joints. They won't be done installing them
until mid April. Then they'll put the oil in as described above and
power it up slowly. I don't expect to have much to report until then and
I promise to send an update.

Assuming 8 month down time the cost of the electricity alone will
approach $75 million!

------

[after many queries of "So how did it all work out?"]

... I am sure that you will all get this final message in due time.

You see, I found out yesterday that even the Department of Water and
Power repair crew got copies! It rattled across electronic bulletin
boards around the country and eventually ended up in the hands of a DWP
manager who promptly showed it to the team. Small world. Every time you
turn over a rock you find that we are all connected.

So, here's the scoop:

They are back on line. The failure was attributed to "TMB", short for
Thermal Mechanical Bending. There have been several similar failures on
the east coast but this was the first out here. TMB causes the cable to
wiggle in place due to load surges. This eventually causes insulation
failure due to abrasion against the pipe and separation of the many
layers of paper tape. They repaired the short, put aluminum collars in
most of the joints to hold the splices in place, and have added a load
management scheme to reduce the current peaks. They powered it up and
the darned thing works. Amazing.

I'll impulse them again in a few months to see if there is any news.

https://www.jwz.org/blog/2002/11/engineering-pornography/



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