Topic
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.
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TL;DR: In this article, a three-wire sensor with two different insulators was used to measure the dielectric constants in non-saline soils and water and in saline soils.
Abstract: In a conducting medium, the energy of a time-domain reflectometry (TDR) pulse is dissipated and the signal is attenuated. Above a certain high conductivity, however, the signal is completely attenuated and the soil short-circuits the sensor. This behaviour of the signal with conductivity severely limits the TDR technique in measuring water content in highly saline soils. By reducing the direct contact between the conductive soil and the metallic sensor the energy of the pulse is better maintained. Different combinations were tried: we insulated the central wire, outer two wires, and all wires of a three-wire sensor with two different insulators. The first insulator was an adhesive polyethylene sheet usually used as a transparent cover and the second insulator was an adhesive tape. The insulated sensors were used to measure dielectric constants in non-saline soils and water and in saline soils. The sensors with the insulated centre wire preserve maximum energy and maintain a clear signal in saline soils. The insulating materials have very small dielectric constants. The TDR exerts a larger influence in the vicinity of the wires of the sensor during measurements. Therefore, the insulated sensor measures a dielectric constant which is smaller than the apparent dielectric constant of the surrounding medium. The type of insulating material also has an effect on the dielectric constant. Therefore, it is necessary to calibrate the sensors for the specific insulator.
29 citations
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28 Mar 1989
TL;DR: An optical fiber composite insulator as mentioned in this paper is a composite of an insulator body having a throughhole formed in its axis portion and at least one optical fiber extending through the throughhole and sealed by an inorganic vitreous sealing material at both end portions of the through-hole.
Abstract: An optical fiber composite insulator which including an insulator body having a through-hole formed in its axis portion and at least one optical fiber extending through the through-hole and sealed in the through-hole by an inorganic vitreous sealing material at both end portions of the through-hole. The sealing material has substantially the same thermal expansion coefficient as that of the insulator body, has high resistances against breakage in the power frequency voltage test and in the lightning impulse voltage test, against crack formation in the cooling and heating test, heat proof test and heat cycle test, and against the light-transmission loss.
29 citations
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TL;DR: In this article, the effect of non-uniformity in the axial and circumferential directions of the insulator surface has a great impact on the ac flashover voltage.
29 citations
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11 Jun 2018TL;DR: In this article, the authors used electrostatic 2D simulations in the AC/DC module to predict the behavior of polluted insulators under AC voltage and applied different conductivity values.
Abstract: The knowledge of the distribution of the electric field within and around high voltage equipment is a crucial aspect of the design, exploitation and performance of high voltage insulators. It could be useful for the detection of defects in insulators. The objective of this study is predicting the behavior of polluted insulator under AC voltage. For thus, the distribution of the potential and the electric field along high voltage insulator is investigated using a numerical method. The commercial Comsol Multiphysics proved to be one of the best software used in 2D modeling. The potential and the electric field distributions along this insulator are simulated under various conditions: the two cases: clean and polluted insulators and applying different conductivity values. We used electrostatic 2D simulations in the AC/DC module. The results are auspicious and promising.
29 citations