[sci.electronics] HV DC transmission lines.

marks@tekigm2.MEN.TEK.COM (Mark D. Salzman) (12/06/89)

In article <8902@swlabs.UUCP> jack@swlabs.UUCP (Jack Bonn) writes:
>I was wondering: what ever happened to the use of high voltage DC for
>power transmission?  I understood that the high voltage inverters
>needed were technologically feasible, yet I've heard very little of
>this since.

HV DC transmission systems do exist. We have one here in Oregon to send
power from our Columbia River power grid to southern California. It runs
at about 1MV DC if memory serves me well.

The problem with this system is that it requires an expensive converter
station at both ends of the line. So it is only used when power is sent
over a very long distance, where the cost of the stations is made up for
by the increase in efficiency of the system. 

-- 
# Mark D. Salzman    Phone: (206) 253-5542.  #  The more complex the mind,
# Tektronix Inc., P.O. Box 3500, M/S C1-936  #  the greater the need for 
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# E-MAIL: marks@tekigm2.MEN.TEK.COM          #       James T. Kirk

ridder@elvira.cxo3.dec.com (Hans Ridder) (12/07/89)

In article <7458@tekigm2.MEN.TEK.COM> marks@tekigm2.MEN.TEK.COM (Mark D. Salzman) writes:
>In article <8902@swlabs.UUCP> jack@swlabs.UUCP (Jack Bonn) writes:
>>I was wondering: what ever happened to the use of high voltage DC for
>>power transmission?  I understood that the high voltage inverters
>>needed were technologically feasible, yet I've heard very little of
>>this since.
>
>HV DC transmission systems do exist. We have one here in Oregon to send
>power from our Columbia River power grid to southern California. It runs
>at about 1MV DC if memory serves me well.
>

The line mentioned here is called the Pacific Intertie.  It was
covered in an article in the 1988 25th Anniversary issue of IEEE
Spectrum.  The article says the line runs at +-500 KV DC (1 MV as
mentioned above), delivering 3100 MW of power by mid-'89.  It also
mentions another DC line delivering 1600 MW from Delta, Utah to Los
Angeles.  They've got this grounding electrode in Santa Monica Bay....
Interesting article....

-hans

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billk@hpsad.HP.COM (Bill Katz) (12/08/89)

	A High Voltage DC transmission system would also be used when power
needs to be moved between 2 AC systems that are not synchronized in phase.
In the US there are 3 different networks (roughly east of the rockies, west
of the rockies, and texas), each of which is synchronous, and at several 
places there are DC interties between them.

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