Quantifying time-dependent structural and mechanical properties of UV-aged LDPE power cables insulations

This paper reports effects of ultraviolet (UV) light radiation on the physicochemical, electrical and mechanical properties of low-density polyethylene (LDPE) cable insulating materials. Changes in structural and morphological properties of UV-aged samples were characterized by various analytical methods such as attenuated total reflection Fourier transform infrared spectroscopy (ATRFTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and atomic force microscopy (AFM). Additionally, elongation at break, tensile strength, dielectric strength, and optical properties were also evaluated. Changes in some physical properties of LDPE after exposing to UV irradiation clearly highlighted that the polymer underwent the structural degradation. In addition, it was also found that such degradation yielded both crosslinking and chain scission as two competing processes during UV aging

Electrical ageing effects on dielectric properties of polymethyl methacrylate

By combining the techniques of dielectric relaxation spectroscopy (DRS), measurement of both ac and dc conductivities, Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM), we have explored the effect of electrical ageing on poly (methyl methacrylate) (PMMA) films at temperature between 0 °C and 80 °C in the frequency range of 1 Hz–107 Hz. These results are discussed and correlated to FTIR and SEM observations

Critical issues in XLPE-based polymer nanocomposites and their blends

Thanks to its excellent properties, cross-linked polyethylene (XLPE) is widely used in the insulation of medium and high voltage cables. However, under service conditions, the insulation of XLPE encounters several problems such as space charge accumulation, water trees, electrical trees, and partial discharges. Recently, research for cable insulating material has shown that nano-size filler added to XLPE may help reducing these problems. Currently, XLPE-based nanocomposites can be used as reliable insulation materials due to its excellent mechanical, thermal, and electrical properties. However, although it offers a number of advantages including its usage as insulator in power cables, some other issues remain to be addressed. In this chapter, the critical issues in XLPE-based nanocomposites are discussed. It includes significant tutorial elements as well as some analyses

Prediction of long-term physical properties of low density polyethylene (LDPE) cable insulation materials by artificial neural network modeling approach under environmental constraints

This study quantifies long-term physical properties of low density polyethylene (LDPE) cables insulations exposed to environmental constraints such as UV radiation and temperature via both experimental measurements and mathematical modeling approach. For this purpose, tensile test and electrical breakdown test were carried out to determine elongation at break, tensile strength, and dielectric strength of unaged and aged specimens, respectively. Experimental results showed that both UV and temperature exposures affected the LDPE properties, significantly. A supervised artificial neural network (ANN) trained by the Levenb erg-Marquardt algorithm was designed for predicting the long-term characteristics of specimens and also for minimizing the experimental procedures. Modeling work showed that the proposed ANN yielded successful estimations and predictions about the service life of thermoplastic cable insulation materials for maintaining the process

Effects of electrical aging on the structural and physicochemical properties of crosslinked polyethylene (XLPE) cable insulation material

The aim of work is to highlight the evolution of physico-chemical properties of peroxide crosslinked polyethylene (XLPE) insulation material exposed to electrical aging. Specific analysis and characterization studies were carried out to determine the effect of electrical aging on different samples at micro and macro levels. Based on the analytical investigations, it was shown that electrical aging yielded significant changes in the chemical and thermal characteristics of XLPE. It was also showed that property loss increased with the aging time

Correlation between structural changes and dielectric behavior of UV-Aged LDPE

Low-density polyethylene (LDPE) is widely employed as insulator for high and medium voltage cable, due to its excellent dielectric, mechanical and other characteristics However, like all other insulating materials, LDPE properties deteriorate after working under different service conditions. One of the most dangerous stressing factors causing a serious degradation for the LDPE insulation properties is UV radiation. In this work, the influence of UV radiation constraint on the LDPE dielectric properties is studied. In order to support this investigation, ATR-FTIR spectroscopy is also performed. The findings indicate that UV radiation influences significantly the material insulating properties