Written by VR Wednesday, 16 February 2011 02:00
In general,the electric fields between any two electrodes can be either uniform and non-uniform.In a uniform field gap,the average field E is the same throughout the field region,whereas in a non-uniform field gap,E is different at different points of the field region.
Uniform or approximately uniform field distributions exist between two infinite parallel plates or two spheres of equal diameters when the gap distance is less than diameter of the shere.Spherical electrodes are frequently used for high voltage measurements and for triggering in impulse voltage generation circuits.Sometimes,parallel plates of finite size are used to simulate uniform electric fields,when gap separation is much smaller than plate size.
In the absence of space charges,the average field E in a non-uniform field gap is maximum at the surface of the conductor which has the smallest radius of curvature.It has the minimum field E at the conductor having the large radius of curvature.In this case the field is not only non-uniform but also asymmetrical.Most of the practical high voltage components used in electric power systems normally have non-uniform and asymmetrical field distribution.
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