Corona ring

About: Corona ring is a research topic. Over the lifetime, 1503 publications have been published within this topic receiving 14530 citations.

EHD study of the corona wind between wire and plate electrodes

Abstract: The corona wind, with a velocity of several meters per second, is caused by applying high electric tension to bring about corona discharge in gases. In this paper the corona wind is experimentally and theoretically analyzed from an electrohydrod ynamical (EHD) standpoint. Experiments have been performed mainly in nitrogen by a two-dimensional electrode arrangement of a fine wire anode and a plate cathode. The voltage-current characteristics of an electrostatic probe indicate that positive ions predominate in the whole space except in an extremely narrow region close to the wire. A theoretical analysis has been conducted based on the model that positive ions produced by ionization near the wire electrode move toward the plate, introducing the bulk convective motion of neutral molecules as the result of collisions of ions and neutral molecules. The electric potential distribution in the space and pressure distribution on the plate calculated numerically agree well with the experimental data. Consequently, it is made clear that the corona wind is caused by the Coulomb force exerted on ions and collisions of ions and neutral molecules of gas.

The mechanism of leader breakdown in electronegative gases

Abstract: A survey is given of the present state of understanding of leader breakdown of electronegative gases in nonuniform field gaps and under fast-rising voltage waveforms. The basic physical processes involved are the formation of a pulsed streamer corona, the transformation of one of the streamers into a leader step, the temporal development of the leader channel, and the stepped propagation of the leader through the gap. The growth and structural characteristics of the corona are modeled and the results obtained are used to derive simple approximations for the spatial corona extension and the corona charge. Two leader inception mechanisms are discussed, namely, the stem and the precursor mechanisms. Inception criteria and characteristic time scales are derived for both of them in terms of the experimental parameters. A simplified model, which also predicts the random aspects of leader propagation through the gap, is presented. Some typical gas-insulation design problems are treated as examples. >

Electric Fields on AC Composite Transmission Line Insulators

Abstract: This paper provides an overview of the electric field (E-field) distribution on transmission line composite insulators applied in alternating current applications. Factors that affect the E-field distribution are discussed as well as the influence of the E-field distribution on the short and long term performance. Modeling and measurement methods are reported and examples of calculated E-field magnitudes determined are presented together with corona ring application information. This paper was developed by the IEEE Task force on electric fields and composite insulators.

method of powering corona discharge in ozone generators

Abstract: A method of supplying electrical power to and controlling corona discharge cells used for the generation of ozone employs a single-cycle discontinuous waveform which is characterized by a fixed pulse width and a variable repetition rate. Discrete bipolar pulses are composed of a pair of unipolar pulses of opposite polarity. The bipolar pulse repetition rate is varied to control the average corona power, providing an infinite turndown of ozone output. When powering discharge cells which are asymmetric in their response to pulse polarity, such as those containing a dielectric coated with a conducting surface as a first electrode and a metal as a second electrode, the present invention configures the first pulse of each pair to make the dielectric electrode electronically negative with respect to the metal electrode. This polarity sequence produces a more stable corona and far less electrical noise. Furthermore, to decrease acoustic and mechanical resonances and fatigue to system components and to the human ear, this invention broadens the frequency distribution of the pulse repetition rate by repetitively sweeping or randomly jittering the intervals between bipolar pulses.