RESONANT OVERVOLTAGES DUE TO TRANSFORMER ENERGIZATION IN THREE PHASE SYSTEMS / ANÁLISE DE SOBRETENSÕES RESSONANTES DEVIDO A ENERGIZAÇÃO DE TRANSFORMADORES EM SISTEMAS TRIFÁSICOS

AUTOR(ES)
DATA DE PUBLICAÇÃO

1982

RESUMO

Transient overvoltages involving transformer energization, in three phase HV systems, deserve special attention in insulation coordination studies due to the very high values that voltages can reach in a period of a few seconds. Some resonant effects can possibly occur due to harmonics in the magnetizing inrush current. The objective of the present study is to analyse resonant conditions with a view to foreseeing the occurrence of very high overvoltages. Chapters 2 and 3 show the physical principles involved and the solution algoritms of linear networks, with special attention to the representation of functions in convergent fourier series, in order to find their harmonic content. Chapter 5 and 6 show digital simulation of transformer energization by means of the EMTP program. The results thus obtained vere submitted to harmonic analysis by digital calculation of Fourier coefficients. Parametric analysis were made to find the influence of transformer connections, switching time, and presence of remanent flux; in voltage and current spectrum obtained by energization of a 600 MVA - 500/138 KV transformer

ASSUNTO(S)

sistemas eletricos transformadores electrical systems transformers surge sobretensao

ACESSO AO ARTIGO

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