Re: History Re: [TCML] Kids class Project

[Jim Lux <jimlux@xxxxxxxxxxxxx>]

>Recently, with the advent of IGBTs and other transistorized devices, the 
>power industry is coming around to using DC lines in certain applications.
>
>Dr. Resonance"
>
>    The "Pacific Intertie" between the northwest and Southern California 
>is such a line.  First line was +/- 400 kV at about 1500 MW and more are 
>planned. 

3000A @ 1MV right now (actually +/- 500kV relative to ground, just like a NST)



 Originally worked with thyratrons [ignitrons??] at the 
>receiving end but now all semiconductor inverters. 

Mercury arc rectifiers and converter tubes, until 1994.  The new "valve hall" is across I5 from where the old one is (new on east side, old on west side) and was built in response to the 1994 earthquake (cheaper to build a whole new facility up to code than try to retrofit the existing hall).

Interestingly, the motivation for changing to solid state wasn't primarily device cost or efficiency, but more about life cycle costs.  The mercury arc converter tubes need to be periodically rebuilt (every 15 years or so?), involving the potential spillage of mercury.  There's also a personnel exposure to mercury fumes issue.



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