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In this paper, the thermal ageing of pressboard impregnated with two kinds of insulation liquids is studied by means of frequency domain spectroscopy which involves the measurement of real and imaginary part of complex permittivity as function of frequency. The magnetic nanofluid was composed by mineral transformer oil as carrier liquid, nanoparticles of magnetite and surfactant. The thermal aging...
Thanks to its large carrying capacity, excellent insulation property and high mechanical strength, insulated tubular bus has been widely used in power stations. Polytetrafluorethylene (PTFE) film which has been utilized as insulating material for the tubular bus is subjected to a great risk of thermal ageing that may degrade its electrical and mechanical properties. From the viewpoint of safety, it...
This paper discusses the dielectric behavior of paper oil insulation using results of polarization and depolarization current measurements of model transformer windings. The effect of temperature, moisture, additives and thermal ageing on the polarization and depolarization current is discussed. This paper also provides a methodology for interpretation of Polarization and depolarization current measurement...
In this paper, the model cables are studied by means of frequency domain spectroscopy (FDS) which involves the measurement of capacitance, the real permittivity and dissipation factor as a function of frequency. Firstly, XLPE cable samples were carried out accelerated thermal ageing at 135 °C. Then, frequency domain spectroscopy was investigated under laboratory condition, including different degree...
In this paper we present the results of a study over the aging and the estimating lifetime of a new insulation system for a DC motor. In order to achieve the lifetime experiments, a group of 7 motorettes (made under IEC 60216-1) have been subjected to accelerated thermal aging at T = 260 ° C (for 1000 hours), followed by their requests to vibrations (1 hour) and humidity (48 hours). At every 200 hours...
“Model” extruded power cables, having a much reduced geometry but using the same extrusion techniques and materials as full-sized cables, have been examined using dielectric spectroscopy techniques to study their thermal ageing effects. Cables insulated with homo-polymer XLPE and co-polymer of XLPE with micron-sized ethylene-butyl-acrylate (EBA) islands were studied by both frequency-domain and time-domain...
A novel deterioration evaluation method of class 1E cable insulation, Polyetheretherketone (PEEK), are proposed by using dielectric relaxation characteristic in order to evaluate the deterioration process for the accelerated aged PEEK. The procedure of accelerated ageing consists of 3 steps, 60Co gamma-ray irradiation, thermal ageing, and loss of coolant accident (LOCA) simulation. Also, the proposed...
Research of thermal, mechanical and electrical effect on lead free solder joints is very important for understanding the reliability of electronic package like BGA assemblies. Combined thermal and electromigration (EM) exposure on SnAgCu BGA solder joint reliability were reported. PBGA assemblies which were soldered on PCB board experienced thermal aging and Thermal-EM combined aging with current...
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