Optimization of HSIL Non-conventional 500 kV Transmission Line

摘要

Eletrobras Furnas, a state-owned Brazilian utility for transmission of large blocks of power throughlong distances, has conducted several research and development (R&D) projects in order to build upmore efficient global solutions for transmission lines. Included in this set of already conducted R&Dprojects, among others, the study of the dynamic behavior of expanded conductors bundles subjectedto high mechanical loading and the technical / economic evaluation of its usage on transmission lines,as well as additional research in an optimization process, rather than, separately, structure andfoundation, the whole structure + foundation, thus further exploring the possibilities of reducing theoverall cost of the transmission lines and still the development of application and computationalmethods with the use of graphical tower type expandable database, in an interactive process withfriendly men / machine interface (MMI), in the form of screens, for easily enabling the evaluation of anumber of tower types / tower heads, allowing to find the most suitable one for each case. Thistechnical article presents the formulation and the results obtained from one of the above mentionedR&D projects conducted by Eletrobras Furnas. The objective of such R&D project was to develop andtest a design of a high capacity transmission line, also known as "High SIL Transmission Line –HSILTL”, with a high degree of optimization that make feasible the transmission of large blocks ofpower, environmentally and economically. New concepts for conductors bundle and new shapes forhardware and towers have been developed in the project, in order to create a complete design of a 500kV HSILTL, with a high degree of optimization. The towers had their mechanical resistance evaluatedfrom the probabilistic approach, considering the variability of properties and models. The amounts ofpower that this HSILTL would be able to transmit and the estimated costs of deployment have alsobeen evaluated. The relationship between these last two parameters identifies the very high degree ofoptimization of this HSILTL design. Testing and validation of the developed solution, both inlaboratory and at site were also part of the R & D project. Thus, in addition to the mechanical andelectrical duty tests applied to fittings and towers in a laboratory of recognized standing - CEPEL, anexperimental real-size HSILTL has been built, resulting in an asymmetric bundle configuration of sixconductors per phase, the first being implemented in Brazil with such characteristics. With theconstruction of the HSILTL the effect of the dynamic mechanical behavior of the bundle ofconductors could be measured and evaluated in real conditions, as well as the performance of solutionsfor cable vibration damping and for construction issues, was all of this being also unprecedented inBrazil. Experimental analysis to obtain parameters and validation of dynamic structural models of theasymmetric bundle will still be carried out at site. It was also established a methodology for live-linemaintenance with operations directly between phases, developed for the configurations of insulatorsstrings, hardware and towers, as well as the design of auxiliary equipment for such maintenance andthe performances of it at site.