From: Marco.Denicolai@tellabs.com
Date: Fri, 25 Oct 2002 11:08:20 +0300
Subject: RE: [TSSP] Top Voltage
Hi Paul,
I think I can find that article, probably in paper form (to be scanned
and emailed).
Gallimberti has been very active in this field, as Les Renardiers (?)
group and others.
There is a huge amount of material available on spark propagation, long
gaps, space charge, etc.
I am really keen to gather those papers, but I would like you first to
specify exactly what you are looking for.
I am developing myself an interest in researching on how the bang
number, period and amplitude (disruptive TC) affects the spark channel
formation. There are 3 possibilities:
1. I get no grant so probably there will be no research (I mean myself)
2. I get the smaller grant, so next year I'll perform the "poor man"
research, limited to current, voltage and "visual" measurements
3. I get also the bigger grant, so next year we'll buy a high-speed
camera (10000 pict/s). I'll be able then to film the spark formation at
that impressive rate.
As you have probably noticed, the majority of the conducted research
uses DC or a single surge pulse. Research with AC, bursts or repeated
pulses is much more limited. Things change under those conditions!
That's why I am asking: what do you intend to find out? I see the danger
to dive deep into a sea of surge stimulated discharge literature, only
to reach for the surface after several months just to state " Ok, we
have measured the same parameters: they just follow a different law".
Please, let me know precisely what we are looking for, so that I can
gather the right papers to you.
Best Regards
P.S. Did you notice this? Large gaps, reactivation, difference from the
basic leader. And old fox Gallimberti has put also his nouse there.
Sounds interesting...
RECORD NO.: 2818748 INSPEC Abstract No: A87020975; B87011984
AUTHOR: Bertazzi, A.; Pigini, A.; Rizzi, G.; Hartmann, G.;
Hutzler,
B.; Riquel, G.; Diaz, R.; Brambilla, R.; Gallimberti,
I.;
Baldo, G.; Badaloni, A.; Pesavento, G.-C.; Stangherlin,
S.;
Poli, E.; Crichton, G.C.; McAllister, I.W.; Vibholm, S.;
Ruhling, F.; Domens, P.; Gibert, A.; Davies, A.J.;
Turri,
R.; Waters, R.T.; Rowlands, A.R.; Martinez, A.R.
CORP SOURCE: CESI, Milano, Italy
TITLE: Double impulse tests of long airgaps. II. Leader decay
and
reactivation
SOURCE: IEE Proceedings A (Physical Science, Measurement and
Instrumentation, Management and Education, Reviews),
vol.133, no.7, p. 410-37
ISSN: 0143-702X
CODEN: IPPRDI
PLACE OF PUBL: UK
TRANSLATED IN: A02
LANGUAGE: English
YEAR: Oct. 1986
COPYRIGHT NO: 0143-702X/86/$2.00+0.00
TREATMENT: X Experimental
ABSTRACT: For pt.I see ibid., vol.133, no.7, p.395-409 (Oct.
1986).
The behaviour of large air-insulated structures
subjected to
complex multiple-peak surge overvoltages is influenced
by
the presence of already established leader overvoltages.
Electrical and optical measurements of leader decay and
reactivation in a 6 m rod-plane gap are described. It is
found that, for a positive leader created by a switching
impulse (SI) of critical time to crest, the leader path
could be rapidly reactivated over at least part of its
length by a second voltage application at times of up to
about 1 ms after its original formation. For longer
times,
new leader growth may still retrace the original basic
leader path. The temporal and spatial characteristics of
the
reactivated leader are substantially different from
those of
the basic leader. The causes of the large statistical
variation in behaviour are discussed. The results
presented
should provide the basis for improved physical knowledge
of
the leader and corona processes, and contribute to
improved
engineering models for insulation co-ordination (0
Refs.)
> -----Original Message-----
> From: paul@abelian.demon.co.uk [mailto:paul@abelian.demon.co.uk]
> Sent: 25. lokakuuta 2002 08:43
> To: tssp@abelian.demon.co.uk
> Subject: Re: [TSSP] Top Voltage
>
>
> Marco,
>
> Is this one available in pdf from your library?
>
> AUTHOR: Bondiou, A.; Gallimberti, I.
> TITLE: Theoretical modelling of the development of the positive
> spark in long gaps
> SOURCE: Journal of Physics D (Applied Physics), vol.27, no.6,
> p. 1252-66
> ISSN: 0022-3727
> YEAR: 14 June 1994
>
> ABSTRACT:
> > The main purpose of this paper is to present a physical
> > model of the positive discharge in long air gaps. A large
> > number of previous experimental and theoretical studies led
> > to the identification of the different successive phases of
> > the spark development: formation and propagation of first
> > corona streamers, inception of the conductive stem at the
> > electrode tip, formation and development of second corona
> > (or 'leader corona') from the stem, and, eventually, the
> > propagation of the leader and leader corona system until the
> > final jump preceding the arc onset.
>
> :)
>
> > Details of the specific modelling of each phase is presented,
> > using the classical equations for conservation of mass, momentum
> > and energy for each particle species. These basic equations are
> > simplified according to the dominant electrostatic, hydrodynamic
> > or thermodynamic processes involved in each step of the spark
> > development.
>
> :))
>
> > The resulting models for simulation of the corona and leader
> > phases are coupled with an analytical calculation of the electric
> > field due to the electrodes, the leader channel and the space
> > charge injected into the gap.
>
> :)))
>
> > The different phase simulation models are expressed with a
> > homogeneous simplification level and then linked
> > sequentially into a complete model, which performs the step-
> > by-step simulation of all the successive discharges phases
> > until the final jump.
>
> o))
>
> > The model described here is self-
> > consistent since the only input data are the electrode
> > geometry and the applied potential wave-shape.
>
> !!
>
> > A good agreement between computed and experimental results
> > has been obtained in various test configurations;
>
> > the model has been also used to simulate the discharge behaviour
> > with perturbations of the applied potential wave and permits the
> > analysis of the conditions for stable propagation of the
> > positive leader. It is shown that some parameters of
> > practical interest, as the 50% breakdown voltage or the time
> > to breakdown can be derived from the proposed model
>
> o))!!
> --
> Paul Nicholson,
> --
>
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