Proteção de sobrecorrente direcional utilizando transformada wavelet

Abstract

Traditionally, the primary protection used in low voltage power systems, as distribution systems, is the overcurrent protection due to its simplicity and low cost. However, in these recent years, the number of distributed generation connected to the system has been growing, which changes the complexity of the system and require a directional module to complement the diagnostic about the fault, providing information whether the fault is forward or reverse according to a reference point. Therefore, in this work is proposed a directional overcurrent protection module based on the stationary discrete wavelet transform. This tool could recreate the standard directional overcurrent protection using just currents and voltages scaling coefficients (low frequency), and the overcurrent protection is recreated by using currents scaling coefficients energy, which overcomes some drawbacks by using discrete Fourier transform. The proposed method was evaluated on the IEEE 30 bus model with distributed generator and the IEEE 230 kV systems analysis with distributed parameters.