Efeito de condições ambientais sob a luz da Norma IEEE 738 na parametrização de relés de distância em linhas de transmissão

• Autor(a) principal: Nascimento, Diogo Andrade do
• Data de Publicação: 2020
• Tipo de documento: Trabalho de conclusão de curso
• Idioma: por
• Título da fonte: Repositório Institucional da UFU
• Texto Completo: https://repositorio.ufu.br/handle/123456789/30039
• topic: Linhas de transmissão; Impedância; Relés de distância; Ventos; Temperatura; IEEE738; CNPQ::ENGENHARIAS::ENGENHARIA ELETRICA::SISTEMAS ELETRICOS DE POTENCIA::TRANSMISSAO DA ENERGIA ELETRICA, DISTRIBUICAO DA ENERGIA ELETRICA

An adequate power system transmission project must agree with certain guiding principles, among them: continuity, reliability, and selectivity of each action. Using a set of equipment that guarantees protection and trustability to the system is necessary − the protecting relay and the circuit breaker. In this scenario, there are distance relays responsible for protecting the transmission lines from possible faults. Although this device is largely used in the electrical sector nowadays, many failures still occur due to its reference impedance’s equivocal adjustment. Often, this error is due to temperature changes in the conductor cable, which cause a change in the transmission line impedance, thus making the adjustment inaccurate. The main factors that cause changes in temperature of the conductor cable - ambient temperature, electric current, wind speeds, solar radiation, and geographical position of the cables - were exhaustively detailed in this work. Therefore, the work’s main objective was to develop a computational system that corrects the impedance of the transmission line from input data related to climatic conditions, according to the IEEE738 standard. For this, the author used the tool SIMULINK from MATLAB software. The obtained results showed that, for sudden variations in the ambient temperature, the conventional relays showed a precision error of up to 16% in the measurement of the transmission line impedance. Another observed case of great relevance was the temperature versus electric current relationship, where the conventional relay had an accuracy error of up to 12% in the impedance measurement. Both the electric current and the ambient temperature are directly proportional to the temperature of the conductor cable. Finally, by correcting the impedance of the transmission line using the input data, it is possible to guarantee a more precise adjustment and a more reliable protection system.