Cálculo da ampacidade de linhas aéreas de energia considerando a influência da camada limite da atmosfera

Abstract

The thermal rating of overhead lines is an important area of research and great economic interest for electrical energy companies. In this context, this work proposes a new methodology of ampacity calculation based on the use of database generated from numerical study of the atmospheric boundary layer - ABL throughout all the spans of a given overhead transmission line. This new methodology presents the advantages: firstly, the results are more realistic and insurance, and secondly, it allows the thermal rating increasing in relation to traditional methodologies during the operation process. The use of numerical data from atmospheric boundary layer analyses in the conductor thermal rating calculation is an original contribution of this thesis. This procedure allows the identification of the critical spans throughout the overhead transmission line path in terms of the wind speed - Vcv. From the transmission line project, it is also possible to extract the set of critical spans in terms of the distance between the conductor and the nearestgrounded objects - Vce. Making the intersection between the two sets, it is possible to determine the set of critical spans à Vc in terms of both criteria, i.e,. Vc = Vcv Vce. Thus, the set of spans belonging to Vc can be monitored in a way much less expensive because of the size of Vc is usually small if compared with the total number of spans of the overheadtransmission line, especially in highlands. The new methodology proposed in this thesis, called of AmpCLA à Ampacity CalculationMethodology for Overhead Transmission Lines taking into account the Numerical Results of the Atmospheric Boundary Layer - was developed in four stages: (I) experimental and numerical investigation were made to understand how the wind speed regionalization affects the thermal rating and ampacity values; (II) development of the new methodology of ampacity calculation - AmpCLA, that considers the influences of the wind speed amplitude variation along the entire line; (III) software development based on the AmpCLA methodology; (IV) AmpCLA validation through the comparison between results gotten with the new methodology and data monitored in real time of an overhead line, in real operation,in the Acuruí (MG), southeastern of Brazil. The afore-mentioned comparison shows, numerically and experimentally, the necessity of considering the amplitude of the wind speed in all spans of the overhead line to generate a safer and more realistic ampacity value, in comparison to traditional methods.