From: boris petkovic
Date: Sun, 3 Nov 2002 08:25:37 -0800 (PST)
Subject: Re: [TSSP] Top Voltage
Hi Bert, > Streamer and leader propagation should occur only as > the top terminal > has an increasing potential - i.e., during ringup - > and not during > ringdown. --- Can you always put your money on this ? I wouldn't.It is a rare event I guess ,butI saw scoping pic of TC where arc attached to a grounded rod during ringdown period .It is indication to me that arc can propagate during ringdown in some situatuations as well. What about leader propation in a natural lightning ? Source (pocket charges of cloud ) doesn't rise difference of potential with respect to ground as leader propagates.The electromagnetic thing (except avearage leader current field)which is increasing is a field at ground surface since leader by its' evolution carries its' strong space charge field. --- If we haven't seen evidence of breakout > during a given > ring-up, we'll likely not see any evidence of > breakout during the the > subsequent ring-down. If we generated corona or > corona streamers, we've > injected space charge into the region near the > terminal. snip;-) --- Yes,this seems to be a problem.According to base cap readings ,OLTC doesn't generate injected space charge if clearly visible breakout happens (or if generates some it must be very small or just diffuse from cycle to cycle).Formed streamers the observer doesn't report in dark either. Therefore it should be a weak ,low energy corona,not being capable to develop in streamers. Perhaps,some minimum space charge density and flux area & shape avilable in vicinity of electrode are necessary as Paul and I suspected are necessary (read our earlier posts)? regards, Boris __________________________________________________ Do you Yahoo!? HotJobs - Search new jobs daily now http://hotjobs.yahoo.com/
Maintainer Paul Nicholson, paul@abelian.demon.co.uk.