Otimização de linhas de transmissão aéreas com vários circuitos em diferentes níveis de tensão na mesma torre

Author(s)

Jhair Stivel Acosta Sarmiento

• Document type: Doctoral Thesis
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Faculdade de Engenharia Elétrica e de Computação
• Defense date: 2021-02-24

Examining board members

Maria Cristina Dias Tavares; Maria Teresa Nunes Padilha de Castro Correia de Barros; Aniruddha Madhukar Gole; Fernando Augusto Moreira; Marco Aurélio de Oliveira Schroeder

• Advisor: Maria Cristina Dias Tavares

Abstract

Multi-circuit lines are a good way to increase the transmitted power using a lesser or similar right of way (ROW) than single-circuit parallel transmission lines. Although double-circuit and multi-circuit transmission lines have been used over the last years, there are few studies about non-conventional multi-circuit multi-voltage transmission lines. Thus, in the present research, it is proposed a mathematical model to increase the surge impedance loading (SIL) level of each circuit, and reduce the total costs, ROW, and height of the towers, by optimizing the tower characteristics through evolutionary computing. The model is solved with two approaches: The weighted sum method and a modified version of the Non-dominated Sorting Genetic Algorithm II (NSGA-II). As a result, it were obtained several non-conventional multi-circuit transmission lines with single, double, triple, and quadruple circuits with an overall improvement in the range of 66 to 152% computing all objectives. After initial results, it was observed that the phase sequence of each circuit in the tower has an important impact on the electric field of the transmission lines, and therefore, in the tower ROW and height. With this optimization, the overall objective function value sum was increased in the best of the cases by almost 30%, because of the additional ROW and height reduction. Regarding the transient behavior, it was observed that each circuit disturbs the others during switching or faults in their own circuits. However, with the addition of the phase sequence optimization, it was observed a reduction in the overvoltage level. Later, neutral reactors schemes were also optimized, aiming to have a successful single-phase auto-reclosing (SPAR). As a result, reductions of up-to 50% in the arc extinction time were achieved. The final part of this research included the secondary arc current (SAC) minimization as a constraint in the mathematical model related to the optimization of the multi-circuit lines. As a result, new optimized transmission lines ready to perform SPAR were achieved. These lines, present SACs with up-to 61% faster arc extinction times. Finally, since the transmission lines satisfy all constraints and have up-to 88% lower ROW than conventional lines, we considered that they are good options to implement in actual transmission line projects that have to deal with severe environmental restrictions (AU)

• FAPESP's process: 15/26096-0 - Increase of the multi-circuit transmission lines capacity by modifying the bundles geometry
• Grantee: Jhair Stivel Acosta Sarmiento
• Support Opportunities: Scholarships in Brazil - Doctorate