nanog mailing list archives
Re: East Coast outage?
From: Jay Hennigan <jay () west net>
Date: Sat, 16 Aug 2003 10:07:30 -0700 (PDT)
On Sat, 16 Aug 2003, Chris Adams wrote:
Basic physics. To run DC at the power levels required, the "wire" would have to be over 100 feet in diameter IIRC. Look up the Edison vs. Tesla power arguments for all kinds of information on AC vs. DC.
Edison and Tesla's arguments took place long before switching power supplies and the development of insulating materials capable of withstanding hundreds of kilovolts. The size of the conductor is a function of IR losses. Losses are a function of the resistance of the conductor and the current passing through it. By raising the voltage, the current drops proportionally for the amount of power delivered, and hence the conductor size also drops. The problem in the Edison/Tesla days was a practical way to convert high voltage DC to low voltage (120 volts or so) power for distribution to homes and businesses. 200KV light bulbs and switches are kind of impractical for home use. :-) The advantage of AC is that a simple transformer can be used to step down the voltage from transmission to distribution levels. Before high voltage semiconductors and switching supplies, high voltage DC transmission was useless as there was no practical means to convert it to the lower voltage levels useful in homes. Rotary motor-generator sets would have been the only choice. Huge, not very efficient, lots of (big) moving parts. Not trivial to maintain. AC still makes sense for distribution, but HV DC transmission lines are becoming the norm. Think about some very large SCRs and associated parts to convert to AC for distribution. -- Jay Hennigan - CCIE #7880 - Network Administration - jay () west net WestNet: Connecting you to the planet. 805 884-6323 WB6RDV NetLojix Communications, Inc. - http://www.netlojix.com/
Current thread:
- Re: East Coast outage?, (continued)
- Re: East Coast outage? Iljitsch van Beijnum (Aug 15)
- Re: East Coast outage? alex (Aug 15)
- Re: East Coast outage? Valdis . Kletnieks (Aug 15)
- Re: East Coast outage? David Lesher (Aug 15)
- Re: East Coast outage? Scott A Crosby (Aug 15)
- Re: East Coast outage? Vadim Antonov (Aug 15)
- RE: East Coast outage? Eric Germann (Aug 15)
- Re: East Coast outage? Iljitsch van Beijnum (Aug 16)
- Re: East Coast outage? Chris Adams (Aug 16)
- Re: East Coast outage? Iljitsch van Beijnum (Aug 16)
- Re: East Coast outage? Jay Hennigan (Aug 16)
- Re: East Coast outage? David Lesher (Aug 16)
- Re: East Coast outage? David Lesher (Aug 16)
- Re: East Coast outage? Michael Painter (Aug 16)
- Re: East Coast outage? hackerwacker (Aug 16)
- Re: East Coast outage? Chris Lewis (Aug 17)
- Re: East Coast outage? Chris Lewis (Aug 16)
- Re: East Coast outage? Chris Adams (Aug 16)
- Re: East Coast outage? Randy Neals (ORION) (Aug 17)
- Re: East Coast outage? David Lesher (Aug 16)
- Re: East Coast outage? Chris Lewis (Aug 16)