Insulator (electricity)

About: Insulator (electricity) is a research topic. Over the lifetime, 15941 publications have been published within this topic receiving 108950 citations. The topic is also known as: electrical insulator.

Flashover of discontinuous pollution layer on HV insulators

Abstract: This paper deals with discontinuous pollution layers deposited on the insulator surface. Two zones are known to form: a clean (dry) zone and a polluted (wetted) zone. The influence of the length and position of the dry zone on the leakage current and the arc length are investigated. These were made on a plane experimental model under ac voltage. Two configurations were studied: pollution deposited near the HV electrode, and pollution deposited near the ground electrode. This study was made using pollution layers with different conductivities. Based on the experimental results, a theoretical model allowing us to calculate the gap impedance, the transferred (gap) voltage and the leakage current was established. This model enables to predict the pollution severity based on the sample's equivalent impedance.

Dielectric-wall linear accelerator with a high voltage fast rise time switch that includes a pair of electrodes between which are laminated alternating layers of isolated conductors and insulators

Abstract: A dielectric-wall linear accelerator is improved by a high-voltage, fast rise-time switch that includes a pair of electrodes between which are laminated alternating layers of isolated conductors and insulators. A high voltage is placed between the electrodes sufficient to stress the voltage breakdown of the insulator on command. A light trigger, such as a laser, is focused along at least one line along the edge surface of the laminated alternating layers of isolated conductors and insulators extending between the electrodes. The laser is energized to initiate a surface breakdown by a fluence of photons, thus causing the electrical switch to close very promptly. Such insulators and lasers are incorporated in a dielectric wall linear accelerator with Blumlein modules, and phasing is controlled by adjusting the length of fiber optic cables that carry the laser light to the insulator surface.

Devices for high-frequency electric power applying, plasma generating, and plasma treating; and methods for high-frequency electric power applying, plasma generating, and plasma treating

Abstract: PROBLEM TO BE SOLVED: To generate plasma under the pressure of high-vacuum degree in a plasma treating device, regardless of applied high-frequency electric power, having a high frequency, thereby to accurately perform plasma treating having high uniformity and low damage. SOLUTION: A lower electrode 12, for retaining an object 13 to be treated, is provided via an insulator 11 on the bottom part in a chamber 10a. In a first high-frequency power source 14, high-frequency electric power is applied to a multi-spiral-coil 15A, consisting of four parallely connected spiral coil parts 15a, via an impedance matching apparatus 16A. The length of respective coil portions 15a to one coil is 1/4 of the wavelength of the high-frequency electric power supplied from the first high frequency power source 14. The second high frequency power source 17 applies high-frequency bias voltage to the lower electrode 12. COPYRIGHT: (C)1997,JPO

Stability of alternating current discharges between water drops on insulation surfaces

Abstract: Discharges between water drops are important in the ageing of hydrophobic outdoor insulators. They may also be important in the processes leading up to flashover of these insulators in high pollution conditions. This paper considers discharges between drops when a limited alternating current is available, as experienced by an ageing insulator in service. A phenomenon is identified in which the length of a discharge between two drops is reduced through a particular type of distortion of the drops. This is visually characterized as a liquid protrusion from each of a pair of water drops along the insulator surface. This process is distinct from vibration of the drops, general distortion of their shape and the very fast emission of jet streams seen in very high fields. The process depends upon the discharge current, the resistivity of the moisture and the hydrophobicity of the insulation surface.