Future Challenges for Cable Accessories in MV Networks by Lukasz Chmura

In recent years, the architecture of power systems has been undergoing a major change. The commonly known structure with centralized generation and uni-directional power flow have gradually been giving way to the concept of a power network where both the energy generators and the energy consumers are distributed. In particular, continuously increasing environmental concerns as well as legal regulations have resulted in more widespread installation of renewables. Moreover, storage devices are now being incorporated into power networks to cope with sudden increases in generated energy. To facilitate energy flow from renewables towards the power network, proper voltage level is maintained by means of transmission controllers that consist of high frequency switching elements. The operation of such devices introduces high frequency harmonics that are propagated in the vicinity of the installed controller. On one hand, high content of harmonics is an emerging issue for power networks. On the other, research has shown that high frequency signals can have a possible deleterious impact on reliability of electrical insulation. Finally, for many years harmonic content has not been considered either during component design or testing. This presentation reviews published research regarding influence of harmonics on reliability of cables, terminations and transformers. In addition, an approach is proposed to model influence of high frequency on electric field and temperature distribution in two types of medium voltage cable termination.