Update I have removed the systems and have moved from this property, so this (incomplete) test has been terminated.
I do not consider the data conclusive. From: Brian O'Connell [mailto:[email protected]] Sent: Tuesday, February 12, 2008 7:55 AM To: 'Emc-Pstc' Subject: RE: possible power line cause of recent San Diego fires Perhaps, over the next calendar year, I can provide some empirical data that would support or deny this theory. I do not intend to release any data or statements to 'journalists' or the general public. Purely for the betterment of humanity (the fact that I have to justify the cost of several Rabbit Semi wireless controller boards to my wife is coincidental), I have installed two solar-powered dataloggers adjacent to power poles - one on my property and another on my neighbors. The local (co-op) utility has been informed and the line supervisor seems interested. Site elevation is 1001m and is located approx 10km north of Palomar mountain (Southern California). During the October 2007 'Santa Ana' winds that spread the wildfires, my weather station recorded (14) gusts exceeding 30 m/sec, and a time-averaged speed of 11 m/sec for approx 78h. The V sensor is a Caddock hi-V divider (rated 10kV) connected >from the guy line to the 'ground' rod attachment. The I sensor is a 200:1 split-core CT clamped around the guy line and has a 1kHz bandwidth (ebay has been good to me). Data logging is continuous and buffered into a circular queue; permanent data storage is triggered by analog comparators that watch both the I and V sensors. For a 500 Hz sample rate, available static storage space is approx 49 min. Data Dump will occur upon client poll of server. I plan to write server-side system to stream from the weather station and correlate guy-line events to weather conditions. Ideas/critique for this project are welcomed. R/S, Brian From: [email protected] [mailto:[email protected]]On Behalf Of Robert Johnson Sent: Monday, February 11, 2008 7:03 PM To: [email protected] Cc: 'Emc-Pstc' Subject: Re: possible power line cause of recent San Diego fires Has anyone done as much as put an amprobe around any of these wires? Bob Johnson [email protected] wrote: Second, if the lines would go arcing all day, under nominal load, the arcing would NOT have gone unnoticed. Nominally, the guys are tight. When we have severe winds (as in October), one of the two guys may become loose as the wind blows on the pole and it bends. Arcing is not likely to be continuous. The transmission lines cross mountains and deserts, and most of their path is away from populated areas and roads. Often, the transmission line neutral is earthed at each end of the transmission line. This would give rise to current in the earth. It all comes down to the question of probability of dry grass, bad contact and current transients, multiplied by the number of poles in the region. Powerpoles are commonly in dry grass. With winds, contacts can be intermittent. Thousands of powerpoles. Best regards, Rich - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <[email protected]> All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher: <[email protected]> David Heald: <[email protected]>
