Wavelet-based ANN approach for transmission line protection

A new approach of digital relays for transmission line protection is presented. The proposed technique consists of a preprocessing module based on discrete wavelet transforms (DWTs) in combination with an artificial neural network (ANN) for detecting and classifying fault events. The DWT acts as an extractor of distinctive features in the input signals at the relay location. This information is then fed into an ANN for classifying fault conditions. A DWT with quasioptimal performance for the preprocessing stage is also presented.