Desempenho da função de sobrecorrente aplicada à proteção de linhas de transmissão: avaliação de falha de seletividade

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Data

2021-01-18

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Editor

Universidade Federal de Goiás

Resumo

The protection of Electrical Power Systems has relays as main components. When there is a defect or disturbance in the system, the relays must be sensitized and, in a coordinated action, they act by isolating the defect by disconnecting the smallest possible portion of the system. This paper aims to analyze the performance of the phase overcurrent and neutral function (ANSI 51 / 51N), in order to check possible situations of improper performance, especially regarding the loss of selectivity. For this purpose, several simulations of fault conditions were applied in a system consisting of two parallel transmission lines, disregarding the magnetic coupling, at a voltage of 230 kV, based on a real system. All modeling was performed in the ATP environment. The following faults were simulated: single-phase, two-phase, twophase-ground, and three-phase. The faults were applied along the entire length of the transmission lines, at intervals of 10% of their length, maintaining a healthy circuit and a defective one. Faults with 0.1 Ω and 40 Ω fault resistance were considered. The results were analyzed according to the TRIP signals of each relay after the fault was applied. It was found that the overcurrent function is insufficient for satisfactory protection of the analyzed system, with regard to the selectivity of defect elimination, considering that situations were observed in which there would be the opening of at least one of the sides of the healthy line. On the other hand, it was observed that the neutral overcurrent function contributes to increase the sensitivity of the protection system, facilitating the adjustment of the phase overcurrent protection, complementing it.

Descrição

Palavras-chave

Electric power systems, Protection of transmission lines, Overcurrent protection, Relay 51

Citação

LABRE, João Victor Moraes; PAULA, Matheus Vicente. Desempenho da função de sobrecorrente aplicada à proteção de linhas de transmissão: avaliação de falha de seletividade. 2021. 17 f. Trabalho de Conclusão de Curso (Graduação) - Escola de Engenharia Elétrica, Mecânica e de Computação, Universidade Federal de Goiás, Goiânia, 2021.