Device having preformed triple junctions to maintain electrode conductivity and a method for making and using the device
In systems where insulating deposits form during normal operation, electrodes are configured with a preformed dielectric thereon, wherein the preformed dielectric is formed with a geometric feature that preforms a triple junction. These triple junctions enhance low level discharge activity to facilitate localized breakdown of the deposits and maintain electrode conductivity.
1. A method of making an electrode, comprising the steps of:
preforming a dielectric layer on a surface of the electrode, the dielectric layer including at least one geometric feature configured to overshadow a portion of the surface of the electrode to create a triple junction at a resulting electrode/dielectric/vacuum interface; and
shielding, with the geometric feature, the portion of the surface from exposure to deposit forming particles in use to maintain the triple junction.
2. The method of claim 1 , wherein said at least one geometric feature is an array of geometric features configured to shield a plurality of portions of the electrode surface from exposure to the deposit forming particles in use.
3. The method of claim 1 , further comprising the steps of:
determining a directionality of the deposit forming particles in an environment in which the electrode is to be used; and
configuring the geometric feature to shield the portion of the electrode surface from deposit forming particles from the determined direction.
4. The method of claim 1 , further comprising the step of forming in situ triple junctions on the electrode during use.
5. The method of claim 1 , further comprising the step of preforming, before use, a conductive shield over the dielectric layer, the conductive shield overhanging at least a portion of the dielectric layer and the electrode.
6. The method of claim 1 , wherein said geometric feature is an angled end face of the dielectric layer.
7. The method of claim 6 , further comprising the step of preforming a conductive shield over the dielectric layer, the conductive shield overhanging at least a portion of the dielectric layer and at least a portion of the electrode surface.
8. The method of claim 7 , wherein said angled end face has a first angled portion forming a electrode/dielectric/vacuum interface triple junction and a second angled portion not collinear with the first angled portion forming a second triple junction at the conductive shield/dielectric/vacuum interface.
9. An electrode having a surface comprising:
a preformed dielectric layer on a surface of the electrode;
the preformed dielectric layer including at least one geometric feature creating a triple junction at an electrode/dielectric/vacuum interface, the at least one geometric feature configured to overshadow a portion of the electrode surface and shield the portion of the electrode from exposure to deposit forming particles in use.
10. The electrode of claim 9 , wherein said at least one geometric feature is an array of said at least one geometric features.
11. The electrode of claim 9 , wherein the at least one geometric feature is an angled end face of said dielectric layer.
12. The electrode of claim 9 , further comprising a conductive shield disposed over the dielectric layer, the conductive shield overhanging at least a portion of the dielectric layer.
13. The electrode of claim 12 , wherein said at least one geometric feature is an angled end face of said dielectric layer having a first angled portion forming said electrode/dielectric/vacuum interface triple junction and a second angled portion not collinear with the first angled portion forming a second triple junction at a conductive shield/dielectric/vacuum interface.
14. A method of generating a localized breakdowns of deposits formed on a surface of an electrode, comprising the steps of :
providing an electrode according to claim 9 ;
orienting the electrode in a high voltage system with the dielectric layer positioned for exposure to deposit forming particles;
said at least one triple junction generating, when the system is in use, localized discharge activity to breakdown at least a portion of the deposits on said electrode.
15. The method of claim 14 , wherein the at least one geometric feature is an array of the at least one geometric features.
16. The method of claim 14 , wherein the electrode further comprises a conductive shield disposed over the dielectric layer, the conductive shield overhanging at least a portion of the dielectric layer.
17. The method of claim 16 , wherein said at least one geometric feature is an angled end face of said dielectric layer having a first angled portion forming said electrode/dielectric/vacuum interface triple junction and a second angled portion not collinear with the first angled portion forming a second triple junction at a conductive shield/dielectric/vacuum interface.