This paper analyzes the problem of occurrence and development fatigue processes in insulation traction motors autonomous locomotives. Factors causing destruction (cracking, delamination, voids) operation have been studied course research. Three characteristic stress cycles (reversible, repetitive, random) were described to make failure predictions. Outcomes investigations temperature conditions...

HVDC cables are subject to several types of impulses superimposed on the rated DC voltage during their service lifetime. Temporary Overvoltages (TOVs) and Superimposed Switching (SSIs) considered some most challenging due relatively long impulse duration. This paper aims at investigating experimentally effect TOVs SSIs XLPE insulation for extruded cables. 0.15-mm-thick DC-XLPE specimens, aged b...

This paper proposes an equivalent circuit model to obtain the transient electrical stress quantitatively in medium voltage frequency transformers modern power electronics. To verify this model, simulation is performed on a 1.5 kV/1 kHz transformer, revealing overshoot between turns and layers of transformer’s HV winding. Effects rise time input pulse voltage, stray capacitance winding insulatio...

During the long-term operation of high-voltage cross-linked polyethylene (XLPE) cables, cable will gradually deteriorate under effect various aging factors. Thermal is one key factors directly related to reliability XLPE cables. In this paper, thermal samples are prepared for PDC measurement. Based on polymer trap theory and extended Debye model, shape curve, depolarization charge, parameters f...

ii I hereby declare that I am the sole author of this thesis. This is a true copy of the thesis, including any required final revisions, as accepted by my examiners. I understand that my thesis may be made electronically available to the public. Abstract Variable speed drives allow for more precise speed control of induction motors, are of high power factor, and offer fast response characterist...

Because of several advantages over traditional ceramic insulators, polymeric insulators are gaining popularity in electrical power transmission and distribution systems as outdoor insulation. However, being organic in nature, these insulators degrade in outdoor environment and their lifeexpectancy needs to be assessed in the environment prevailing at potential sites of outdoor installation. For...

The state of cellulosic solid kraft paper (CSKP) insulation, to a large extent, is an indication transformer’s health. It not only reflects the condition transformer but also diagnose its residual life. quantity 2-furfuraldehyde (2-FAL), carbon dioxide (CO2), and monoxide (CO) dissolved in oil are useful diagnostic indicators predict CSKP insulation. In this work, current physical determined wi...

Frequency Domain Spectroscopy (FDS) is widely used to estimate oil–paper insulation. The high moisture and long aging change the FDS characteristics of insulating oil–paper, so normalization processing required. Still, choice single activation energy needs further research. This paper studies characteristic insulation samples with different degrees improves traditional temperature correction me...