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.

Quantification of corona discharges on nonceramic insulators

Abstract: This paper attempts to establish a correlation of the visual images of corona obtained from a camera with discharge magnitude measured with conventional partial discharge equipment. A linear relationship is shown between the transformed image parameters and the discharge magnitude, thereby providing a means for quantifying corona observations made during routine maintenance inspections, of insulators from ground. Different insulator designs using silicone rubber (SIR) and ethylene propylene diene monomer (EPDM) housings were examined. The effect of fog has been examined by performing experiments inside a fog chamber. It is shown that this information can be used along with the corona degradation characteristics of housing materials to identify discharge patterns that can pose problems to the integrity of the insulator.

Dynamic behavior of surface charge on direct- fluorinated polyimide films

Abstract: Polyimide film, as a special type of engineering plastic film, is a kind of basic insulating material and is widely applied in the aerial, nuclear, microelectronic industry, turn to turn insulation and turn to ground insulation of inverter-fed motors. However, premature insulation failures occur frequently in motors with the disadvantage of pure PI inherent in all organic materials. The existence of surface charge has a great effect on breakdown characteristic and is the main reason leading to dielectric breakdown. Fluorination as change the chemical component in surface layer of polymers should give rise to the corresponding change in electrical properties of the surface layer thus influence the charge injection from electrodes when they are used as an insulator. This paper presents a study aimed at clarifying the effect of fluorination time on surface charge accumulation and decay behaviors of fluorinated polyimide film. Samples were surface fluorinated in a laboratory vessel at about 328 K (55 °C) using a F2/N2 mixture with 20% F2 by volume and 0.05 MPa (500 mbar) for respectively 15, 30, 45 and 60 minutes. Corona charging tests were performed at room temperature with a relative humidity of ~ 40%. The charge distribution was measured by means of an electrostatic voltmeter. Obtained results show the dependence of the charge density as well as the charge decay rate upon the fluorination time of samples, varying as a function of the charge polarity and charging time. It is suggested that the fluorination can significantly improve the decay rate of the surface charge in polyimide films.

Aging of 154 kV underground power cable insulation under combined thermal and electrical stresses

Abstract: This work the combined electrical and thermal stresses of the 154 kV XLPE power cable used in the underground power transmission in Turkey. The dependence of aging on electrical and thermal stresses is given by a straight line in a certain range of electric field (E) values which indicates that the aging is a thermochemical process. Furthermore, cable tests are conducted in oil, and the results are valid for immersed insulation but might not be completely representative of XLPE used in service in a "dry" environment. Therefore, each cable insulator has to be tested and the parameters must be determined for each cable separately.

Metal-insulator-semiconductor tunneling contacts

Abstract: A contact to a source or drain region. The contact has a conductive material, but that conductive material is separated from the source or drain region by an insulator.

Self-consistent electrical charging of insulating layers and metal-insulator-semiconductor structures

Abstract: By means of a computer simulation the self-consistent charge transport with the current densities j(x,t), the respective charges ρ(x,t), field strengths F(x,t), and potential distributions V(x,t) in SiO2 layers are obtained as a function of the insulator depth x and the injection time t. The SiO2 layers are considered as open layers on silicon substrate or they are embedded in metal-oxide-semiconductor (MOS) structures. The given currents of primary electrons, the field-dependent ballistic currents of secondary electrons and holes as well as the Fowler–Nordheim injection of electrons from the substrate into the dielectric layer are taken into account. This method allows a defined charge storage and the explanation of complicated emission, charging-up, and breakdown processes within insulating layers during electron bombardment and/or high-field charge injection from adjacent electrodes, e.g., in MOS structures.