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.

Dielectric breakdown of epoxy-based composites: relative influence of physical and chemical aging

Abstract: The effect of aging on the dielectric strength of epoxy-inorganic particle composites used for insulators in the high voltage industry is reported. A differential scanning calorimetry analysis of an insulator aged twenty years in actual service conditions indicated both a chemical degradation and a structural recovery of the polymer network. This composite exhibited however a breakdown field comparable to that of a fresh sample with the same formulation. An accelerated physical aging was thus performed which lead to a large increase in the high voltage performance of the newly processes composite over time. This improvement was attributed to a densification of the thermoset resin, which impeded tree growth. It was also observed that the choice of the electrode geometry greatly alters the measurements under high electric field. In a quasi-homogeneous field configuration, the breakdown was mainly governed by the major flaws at the sample scale, namely the reinforcing particles. On the contrary, under a divergent field (with a point-plane electrode arrangement), the field was essentially localized at the point electrode tip, and the major flaws might not be reachable by the damage tree. It hence appeared that the measurements performed in a quasi-homogeneous field are not very sensitive to the variations within the polymeric matrix as are the measurements under a divergent field.

Effect of hydrophobicity coating on insulator icing and DC flashover performance of iced insulators

Abstract: How to decrease the ice on insulators and increase the flashover voltage of iced insulator are hot topics of power system in the world. Many tests have been carried out to investigate whether the permanent room temperature vulcanized (PRTV) coating can change the electrical characteristics of iced insulators both in laboratory and field. Firstly, the test to investigate the icing and electrical characteristic of dc insulator with PRTV coating was carried out. Moreover, comparison has been made between artificial polluted insulator and field polluted insulators. Results indicate that the PRTV coating can not decrease the ice accretion on insulators. Instead, it results in accumulating more ice at the beginning of icing regime, but the influence of PRTV coating will not be remarkable to accumulate ice when there is heavy ice on insulators. . In addition, the PRTV coating can decrease the flashover voltage by 10%. It is also revealed that the flashover voltage for the artificial polluted insulators is lower than that of the field polluted insulators due to the non-uniform of the natural pollution.

A Cumulative Pollution Index for the Estimation of the Leakage Current on Insulator Strings

Abstract: The pollution performance of insulators installed in transmission and distribution lines plays a key role in maintaining the reliability, safety and cost-effectiveness of power systems. Among the different insulator monitoring techniques, leakage current stands out as one of the most meaningful pollution performance indicators as it gives a measure of how close the insulators string is to flashover. This paper presents a novel methodology for the prediction of the leakage current on insulator strings considering the environmental and weather information of the insulators location. It is based on the combination of a new developed Cumulative Pollution Index (CPI), which estimates the soluble pollution deposit on the insulator string, and a machine learning technique such as Random Forests algorithm. The method is valid for ceramic insulators, i.e., toughened glass, as well as RTV silicone-coated insulators with hydrophobic transfer properties. The research is supported by an extensive field monitoring program where three different insulator strings composed by non-coated, half-coated (bottom part) and full-silicone-coated glass insulators were monitored in a period covering twenty-two consecutive months. Finally, the performance of the proposed prediction model is evaluated using real data.