الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
The theoretical criterion for the onset of negative
corona is suggested for no uniform field gaps. This criterion is based on the physical processes that govern the negative corona pulse formation. This pulse will form when an electron avalanche must somehow provide an electron from the cathode surface to start the successor avalanche. The emission of such electron from cathode surface is mainly due to photons while the contribution of positive-ion bombardment is insignificant. The calculated corona onset voltages agree well with experimental observations. The corona onset voltage is found to increase with cathode radius as well as with the gap length. The actual variation of corona onset voltage for different points on the cathode periphery is predicted. The present calculations confirm the fact that the corona discharge starts on a limited part of the cathode circumference and extends tangentially
as the applied voltage increases.
When do corona discharges occur on a conductor subjected to high voltage, the electric field at its surface gets modified by the ion space charge built up. A method is suggested for the calculation of the electric field strength at the conductor surface based on the solution of Poisson’s equation in the corona layer under a properly specified boundary conditions. The agreement between the calculations, and the corresponding measurements made for coaxial cylindrical arrangement is quite satisfactory. It is found that the electric field at the surface of a smooth conductor at which a corona discharge is present is reduced below the onset value. With practical conductor sizes, the field during the positive corona discharge was up to 7% below the onset value. t and was independent of corona current. For the negative discharge, average fields of up to 17% below the onset value were predicted. The present
method of calculation can be relied on where experiment is too difficult to carry out.
Existing methods for calculating corona losses on
monopolar and bipolar do transmission lines have resorted to the assumption that the space charge of corona does not
effect the direction of the electrostatic filed. This
assumption was aimed at making the calculations possible.
In the present work, calculations of corona loss are made in which this assumption and others are replaced by correlating the corona space charge density to th0 avalanche growth inside the ionization zone at the hv conductor. This approach is more realistic, gives better agreement with experiment and needs much less computer time.
A model of corona discharge is suggested for calculating the chaps of Trichel and onset-streamer pulses, their amplitudes and repetition rates. Thus, the radio interference RI of corona is predicted as depending on pulse characteristics.
The corona Trichel pulse is calculated as corresponding to a main avalanche followed by its successors which develop in the ionization zone. The number of successor avalanches growing in the ionization zone and their respective starting instants as well as their respective time of production are calculated using the basic theories of gas discharges.
A theoretical analysis of the effects of wind on
corona pulse characteristics is also presented. The
analysis is based on the effects of wind on the growth of an electron avalanche related to the mechanisms of corona pulse discharge.
The effect of wind on corona pulses of both polarities is found to increase the time interval between pulses and the total charge per pulse. Thus, the RI of corona is correlated to wind and its calculated increase with wind confirms previous experimental findings.