From: boris petkovic
Date: Sat, 26 Oct 2002 09:21:21 -0700 (PDT)
Subject: Re: [TSSP] Top Voltage
Hi Paul,All,
Paul wrote:
> There appears to be off-the-shelf physical
> quantitative models
> available for each stage of the breakout process:
> corona onset,
> diffuse corona (streamers), streamer-leader
> transition, leader
> development.
>
> These models extend to discharges inhibited by
> finite source
> charge and resistance.
>
> They seem to involve straightforward integrals over
> field
> quantities, with things like coefficients for
> ionisation,
> recombination, etc.
---
I'm glad to hear there's a large amount of avilable
publications on the subject.Surely,that is helpful.
But something bothers me.Bert and Marco both mentioned
there was concentration in the papers just on positive
discharges.How come?What's that special about positive
electrode over negative one?I remind others that we
need both polarities succesive waves effects to
examine in detail.
Maybe ,it is too early to consider leader(s)
development stages,or even corona-leader ignition
phenomena ,since we haven't got straigtened even
avalanche-streamer transition stage in case of OLTC,
but oscillating nature of TC wave in early stages of
gas excitation might have influnce to latter more
powerful events too.
Speaking of which,how is ceiling construction progress
,Terry?
Paul,despite what you think that first we should take
some time to study avilable publications before
serious experimentation/msms on OLTC,I think some
preliminary scoping tests under obvious breakout would
come in handy.Only problem here is the requirement of
the high precision of scoping.We should be looking
for a very small changes in Fr (say 0.1 %) due to
possible presence of low energy loading (single pulse
mode meant ,of course).
---
> I begin to
> see now why breakrate, frequency, and coupling will
> have a big
> impact on the breakout.
---
Yes.The sea of varitions there.
---
> there and some effort will be required to filter out
> the relevant
> bits without drowning in information and getting
> hopelessly lost.
---
Huh..I agree.
---
>
> Hopefully, we can achieve our aims without having to
> do any
> original research of our own. We can continue our
> tradition of
> working from well established physical principles -
> no need to
> launch off into the dark.
---
I'll be happy if the mentioned outcome will be
reached.
However,nobody before have studied seriously impulsive
gas discharges of Tesla coils at academic level.
And no wonder knowing all the difficulties associted
with this task.
---
>
> To summarise our goals as a guide to what info is
> relevant:
>
> Our good understanding of the secondary needs to be
> extended
> to account for the interaction with breakout
> loading. We would
> like to be able to predict the breakout performance
> of a TC,
> given the geometry and firing voltage.[*]
---
You see what I mean.As of now,we are stucked already
in first step.Not to mention what comes later..
Hope the things will change for better soon as
concerns first step.Than we'll give a thought of how
to proceed with next step.
---
>
> Predicting the performance, in this sense, means
> being able to
> estimate the typical number and length of inhibited
> leaders when
> discharging into air, for a given firing voltage.
---
Ah,this would be the last step.Still a long way to
come to it.
---
>
> To do so, we will likely have to take account of the
> dynamically
> varying load applied to the secondary, working in
> the time domain
> to derive a numerical solution to the non-linear
> system. Only then
> will we cope with arbitrary topload waveforms (wide
> range of Ctop,
> Fres, and k).
---
Bottom line is that slight variations in Fr of
secondary could be present without any inhibited
leader attached to a terminal.
----
We'll
> just have
> to see how things come out.
---
Usual modus opearandi of an every research .
---
>
> I'll start a new web page this weekend to summarise
> existing
> applicable research on breakout phenomena. I'll use
> it to keep
> track of which references we need to obtain or have
> got, so that
> Marco will know exactly what to go for.
---
Very good.
regards,
Boris
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