FERNANDES JÚNIOR, D.; http://lattes.cnpq.br/3630883713661678; FERNANDES JÚNIOR, Damásio.
Resumo:
CHESF (Companhia Hidroeletrica do Sao Francisco) has reported
unexpected overvoltage protective device operations in several coupling capacitor voltage
transformers (CCVTs). This has affected the reliability of the power system and caused
failure in some CCVTs. In this work, a first step is given towards the solution of the
problem. A method to obtain the CCVT parameters (resistances, inductances and
capacitances) from the frequency response curve, is proposed. Frequency response
measurements, in the range from 10 to 10 kHz, were carried out in a 230 kV CCVT at the
High Voltage Laboratory and used as input data to a nonlinear fitting routine. The
measured data were fitted to an analytical CCVT function. The magnitude and phase
errors, in the whole frequency range, were fairly small. The obtained CCVT model may
easily be used in connection with the EMTP (Electromagnetic Transients Program).