The distributed generation is one of the most important topics that impact the electrical grid it has increased significantly due to the reliance on renewable energy. Moreover, the recent rise in numbers of electric vehicles introduced to the distribution grid may cause serious impact on the low voltage distribution cables. The purpose of thesis work is to study the life expectancy of the low voltage distribution cables in case of these new factors.
Chapter 1 introduces a literature review about the low voltage cables, the life expectancy based on Arrhenius law and IEC 943 guide, the distributed generation technologies, its impact on the voltage regulation, harmonics and short circuit level. The increasing penetration of the distributed generation leads to the high variation of load which can increase the current flow in the cables consequently their temperature rise, which results in a shorter lifetime which is known also by the load changing of cables is investigated too.
Chapter 2 introduces some types of electrical condition monitoring used during the accelerated aging process of low voltage cables such as insulation resistance and tan delta which used in the evaluation of the aging. Thermal modeling of low voltage underground cable based on IEC 60287 standard and portable power cable are introduced. Simulation for the temperature distribution and the total heat flux through the cable are done by Ansys software, the calculated maximum stress in the insulation material is simulated using ETAP software.
Chapter 3 introduces an overview of the reliability analysis which is used in the life expectancy of cables and Weibull distribution as a specific distribution for the failure modes. Finally, conclusion and recommendation are presented.