Corona and arcing in power and RF devices

Abstract

The electric field between the surfaces of two conductors exceeds a critical value, a self sustaining ionizing discharge that typically occurs between the closest surface areas called corona. The corona initiates arcing and the arcing can ignite fire. There is both power loss and generation of RF interference during corona. Under certain circumstances corona could shorten the service-life of electrical insulations. The corona due to high frequency is still a research topic. Some studies indicate that corona due to RF fields occur at lower voltages compared to power frequencies. If the onset of corona is minimized, the arcing in electronic and electrical systems would be automatically eliminated. This paper describes corona onset characteristics under temperature, pressure and humidity changes in AC, DC and RF circuits. The multipacting discharge phenomena that occur in high voltage high RF frequency circuits are discussed. A frequency domain technique for measuring corona onset also discussed. The corona due to AC power voltages is modeled as RC equivalent circuit and rise time of corona is computed.

Ozonization of Water, Retention of Ozone and Devitalization of Escherichia Coli in Water By Ozone

“…Mineral content affects the diffusion of the ozone bubbles into the water, the higher the mineral content, and the easier the ozone to be decomposed and thus causes the retention time of ozone to be shorter. [13]. According to V o n G u n t e n [18], ozone firstly decomposed inorganic compound then organic compounds will be decomposed afterwards.…”

“…Ozone generators are high voltage electric machines, with all the safety implications involved. Moreover, the corona effect, whichever the frequency of the applied current, produce a broad spectrum of radio frequencies depending on many different parameters [13]. The European Chemical Agency (ECHA) safety guidance forbids the entire room where the ozone generator is deployed to pacemaker bearers.…”