This document presents a novel technique for fault detection and classification on double circuit transmission lines using artificial neural networks (ANNs). The technique uses high frequency transients caused by faults to identify internal and external faults. ANNs with suitable numbers of neurons are used to analyze voltage and current signals and decompose them to identify faults. Extensive simulation studies show the proposed approach can accurately discriminate between internal and external faults, providing fast, effective, and efficient protection. The document describes modeling a double circuit transmission line system in MATLAB, selecting ANN input/output parameters, developing a 3-layer 45-neuron ANN structure, and presenting simulation results demonstrating the ANN can detect and classify different fault types within a few milliseconds.