Talk:Partial discharge

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==PD Comments/Questions under this heading please==q To all interested in this page Please do not start to confuse partial discharges with corona discharge or we will get into a heck of a mess. Corona is not in my view, the same as partial discharge.

Partial discharges always occur inside the dielectric of a cable or transformer windings. Corona is a surface phenomenon occuring on overhead lines and their insulator strings etc.LC

[edit] Corona and partial discharge

Not sure how corona can occur in solid insulation. It can occur in air,gases maybe even liquids. But solids?? I don't think so, Can anyone explain this??Light current 23:31, 8 August 2005 (UTC)

Kuffel & Zaengl (K&Z from now on) say PD can occur in any combination of solid, liquid, or gas and that corona is sometimes grouped under the term partial discharge. However in the industry, corona and partial discharge are treated as two distinct phenomena. Includes a wide variety of discharge phenomena. (K&Z)Light current 14:14, 13 August 2005 (UTC)

There is a great deal to say about partial discharges and their measurement. I have worked on and with instrumentation to do just that. Maybe best get a word from Bert to confirm what I say as some people dont seem to believe me. He seems to know a lot about corona etc. Light current 06:25, 8 August 2005 (UTC)

Dielectric breakdown within liquids and solids is considerably more complex and less understood than within gases. However, breakdown within either solids or gases seems to be preceeded by the formation of gas-filled cracks or bubbles which have significantly lower dielectric strength than the parent dielectric material. Once these voids form, you will get corona/PD within them (hence the K&Z comment). You can increase the breakdown voltage of oil by putting it under pressure (thereby helping to prevent initial bubble formation). However, there are a number of other mechanisms that can also lead to internal field concentrations and treeing/breakdown, such as long term space charge injection within solid and liquid dielectrics, alignment of particulates along E-field lines in iquids, etc. I've modified the wording a bit in the PD article to provide a bit more information on the physics/chemistry underlying the phenomenon. Bert 15:08, 2 April 2006 (UTC)

Linked Partial Discharge to newly created Electrical Treeing article, since older "treeing" article only discussed hunting dogs. Bert 17:34, 1 April 2006 (UTC)

Yes we used to do all this sort of work, but discharges inside insulation were always refered to and treated as PD. How would you know corona is happening deep inside a solid and be able to tell the difference from PD by external measurements? Can corona and PD be lumped together in one measurement of discharge magnitude I wonder?--Light current 17:34, 2 April 2006 (UTC)

[edit] Drawing diagrams for this page

HELP!! dont know how to do diagrams. can someone advise me of best drawing package for both mechanical drawings and cct diags for import into WP?. THanx Light current 14:27, 13 August 2005 (UTC)

There is no best drawing package.  :-) Different people use different things. The only requirement is that photographic images are in jpeg format and diagrams and such are in png format. See Wikipedia:Graphics tutorials, User:Omegatron#Electronics diagrams, Wikipedia:How to create graphs for Wikipedia articles. I use the GIMP, Inkscape, and Klunky, as described on my userpage. - Omegatron 22:57, August 13, 2005 (UTC)