Representação de linha de transmissão com geometria não uniforme para estudos de sobretensões atmosféricas

Abstract

Modern electric power networks are facing a time of great challenges and demanda suitable knowledge of all equipment involved in the process. For instance, there are scenarios where the well-known premises regarding the evaluation of per unit length impedances and admittances cannot be fully applied, such as in the crossing of wide-rivers. In this scenario, all components involved, i.e., overhead conductors, towers and grounding system, must be represented as nonuniform lines, thus representing a challenge for the lightning performance evaluation. This thesis deals with an investigation regarding the adequacy of distinct formulations of overhead transmission lines when nonuniform spans are considered as well as different approximations for the grounding system. The results indicate that the conventional approach using a cascade of uniform lines might lead to numerical instabilities if tall towers are involved. The results also indicate that the grounding system has a lesser impact and alternative approaches might be needed.