This article deals within the study of the effect of artificial radiations on physical and chemical properties of the crosslinked polyethylene (XLPE) material, widely used for manufacturing high-voltage cables. Within this framework, several experimental tests, using essential characterization techniques, were performed to study XLPE behavior under ultraviolet (UV) aging. Attenuated total reflection Fourier transform infrared spectroscopy, differential scanning calorimetry, thermogravimetric analysis, X-ray diffraction, and scanning electron microscopy were thus carried out to identify the main structure changes of the material before and after exposure to UV. In addition, appearance changes and DC (Direct Current) volume resistivity were evaluated. The obtained results showed that UV radiation has a great effect on the physicochemical properties of XLPE cable insulation.

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Under operating conditions effect, insulated power cables can undergo critical degradations. Ultraviolet (UV) radiations are one of the most destructive constraints which affect the properties of the material used for insulation. Because of its good properties, crosslinked polyethylene (XLPE) is widely used in medium voltage (MV) and high voltage (HV) cables insulation. Regardless of its excellent performances, XLPE can degrade when exposed to UV. The objective of this work is to report experimental results concerning the effect of accelerated UV ageing on the properties of XLPE insulation. For this purpose, dielectric characterization, visual observations and scanning electron microscopy (SEM) analysis are performed to assess the extent of ageing. Obtained results show that UV ageing affects greatly the XLPE insulation. So, an evolution in the dielectric properties (dielectric constant, dissipation factor, dielectric loss index and AC volume resistivity), color change and deterioration of surface morphology with ageing time are noticed.

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This paper deals with the behavior of the crosslinked polyethylene (XLPE) used as high-voltage power cable insulation under ultraviolet (UV) radiations. For this, XLPE samples have been irradiated for 240 h using low-pressure vapor fluorescent lamps. Electrical (surface and volume resistivities), mechanical (tensile strength, elongation at break and surface hardness) and physical (weight loss, water absorption, work of water adhesion and contact angle) tests have been first carried out. Experimental results show that the XLPE characteristics are affected by UV radiation. Indeed, a decline in surface resistivity, mechanical properties, and contact angle, and an increase in the water retention amount and weight loss have been recorded. In order to predict and extrapolate some XLPE properties, a supervised artificial neural network (ANN) trained by Levenberg-Marquardt algorithm has been designed. The collected database is used to train and test the ANN performance. The obtained results show that the proposed ANN algorithm presents good estimation and prediction since the predicted output values agree with the experimental data.

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In this paper, a comparative study between two open ended coaxial sensors with and without cavity is presented. Those sensors are used for materials characterization (composite, dielectric, liquid) and surface defects detection. First Galerkin’s method in the Fourier transform domain is applied to the determination of the resonant frequencies of an open-ended coaxial sensor. The obtained results are used for the realization of two open ended coaxial sensors with and without cavity. The defects detection testbed includes a network analyzer, two open ended coaxial sensors and two aluminum plates with defects of various depths. The proposed method is based on the reflected electromagnetic waves from defected surface, wish are captured by a coaxial sensor. The behavior of the sensor is then studied through reflection coefficient measurements for each kind of defect. A comparative study between the realized sensors is also carried out.