State estimator and convolutional neural networks-based fault localization approach for modern grids

Direct current distribution networks get more attention due to the high penetration of renewable energy-based distributed generation. However, these networks face protection challenges like detecting, classifying, and localizing faults. This manuscript proposes a two-stage approach for identifying and isolating faults within these critical networks. The first stage uses a cubature Kalman filter to estimate the state of the measured current and voltage signals at the faulty bus. These estimated signals represent various fault scenarios and serve as convolutional neural network training data. Then, a total harmonic distortion index was computed from the estimated fault current for fault detection. Moreover, the direction of this reactive power is then utilized to classify the fault type and locate faulty sections in these networks. Extensive simulations demonstrate that the proposed scheme achieves fault detection under five milliseconds, exhibits 98% accuracy, and requires reasonable computational resources.