Recurrent neural network (RNN) is one of the most used deep learning techniques in fault detection and diagnosis (FDD) of industrial systems. However, its implementation suffers from some limitations presented in the hard training step and the high time complexity. Besides, most used RNN-based FDD techniques do not deal with system uncertainties. Therefore, this paper proposes enhanced RNN techniques that detect and classify faults in wind energy conversion (WEC) systems. First, we develop a reduced RNN in order to simplify the model in terms of training and complexity time as well. Reduced RNN is based on Hierarchical K-means clustering to treat the correlations between samples and extract a reduced number of observations from the training data matrix. Second, two reduced RNN-based interval-valued-data techniques are proposed to distinguish between the different WEC system operating modes. The proposed techniques for interval-valued data are able to improve both fault diagnosis robustness and susceptibility while maintaining a satisfactory and stable performance over long periods of process operation. The presented results confirm the high feasibility and effectiveness of the proposed FDD techniques (an accuracy greater than 98% for all the proposed methods).

Modern photovoltaic (PV) systems have received significant attention regarding fault detection and diagnosis (FDD) for enhancing their operation by boosting their dependability, availability, and necessary safety. As a result, the problem of FDD in grid-connected PV (GCPV) systems is discussed in this work. Tools for feature extraction and selection and fault classification are applied in the developed FDD approach to monitor the GCPV system under various operating conditions. This is addressed such that the genetic algorithm (GA) technique is used for selecting the best features and the artificial neural network (ANN) classifier is applied for fault diagnosis. Only the most important features are selected to be supplied to the ANN classifier. The classification performance is determined via different metrics for various GA-based ANN classifiers using data extracted from the healthy and faulty data of the GCPV system. A thorough analysis of 16 faults applied on the module is performed. In general terms, the faults observed in the system are classified under three categories: simple, multiple, and mixed. The obtained results confirm the feasibility and effectiveness with a low computation time of the proposed approach for fault diagnosis.