Proposed Fault Diagnosis Model Research Articles

Research on fault diagnosis of electric gate valve in nuclear power plant based on the VMD-MDI-ISSA-RF model

Electric gate valve (EGV) is an essential equipment within nuclear power plant (NPP). This paper presents an advanced fault diagnosis (FD) approach, leveraging Variational Modal Decomposition (VMD), Mutual Dimensionless Indicator (MDI) and the Random Forest (RF) optimized through Improved Sparrow Search Algorithm (ISSA), aimed at improving the accuracy of fault diagnosis and optimizing the FD model during EGV failure events. To commence, we employ the VMD algorithm for modal decomposition of raw electric gate valve signals. This process yields several Intrinsic Mode Function (IMF) components with diverse frequencies, enabling the capture of the underlying dynamics of the signals and facilitating a more comprehensive analysis of the fault conditions. We subsequently apply the K-L divergence to identify key IMF components that closely resemble the original signals. These selected key IMF components serve as the foundation for extracting dimensional indicators (DI) and mutual dimensionless indicators (MDI) as signal features. Furthermore, the Improved Sparrow Search Algorithm (ISSA) is enlisted to optimize the maximum feature count and the number of decision trees in the Random Forest (RF) algorithm. Ultimately, the optimized RF algorithm is deployed for fault diagnosis. Our paper offers a comparative analysis, pitting the VMD method against Empirical Mode Decomposition (EMD) and Local Mean Decomposition (LMD). Additionally, we compare our proposed fault diagnosis model with traditional RF algorithm and the SSA-RF algorithm. Through rigorous experimentation, our results achieved an average fault diagnosis accuracy of up to 96.375%.

Multi-scale deep residual shrinkage networks with a hybrid attention mechanism for rolling bearing fault diagnosis

The fault diagnosis of rolling bearings based on deep networks is hindered by the unexpected noise involved with accessible vibration signals and global information abatement in deepened networks. To combat the degradation, a multi-scale deep residual shrinkage network with a hybrid attention mechanism (MH-DRSN) is proposed in this paper. First, a spatial domain attention mechanism is introduced into the residual shrinkage module to represent the distance dependence of the feature maps. Then, a hybrid attention mechanism considering both the inner-channeled and cross-channeled characteristics is constructed. Through the comprehensive evaluation of the feature map, it provides a soft threshold for the activation function and realizes the feature-map selection adaptively. Second, the dilated convolution with different dilation rates is implemented for multi-scale context information extraction. Through the feature combination of the DRSN and the dilated convolution, the global information of the rolling bearing fault is strengthened and preserved as the fault diagnosis network is deepened. Finally, the performance of the proposed fault-diagnosis model is validated on the dataset from Case Western Reserve University (CWRU). The experimental results show that, compared with common convolution neural networks, the proposed neural diagnosis model provides a higher identification accuracy and better robustness under noise interference.

Power transmission system’s fault location, detection, and classification: Pay close attention to transmission nodes

For transmission systems to operate safely and reliably, fault identification and classification are essential. However, power network physical architecture and data information cannot be fully utilized by conventional intelligent approaches. This study,therefore,presents a fault localization, detection, and classification model for transmission systems that concentrate on the key distribution nodes. The model makes use of a deep graph neural network with multi-scale attention and multi-linear perceptron block which accounts for the power network's structural composition during learning. The model's capacity to manage unusual data input and unidentified application situations is improved by the inclusion of multi-scale attention. Furthermore, it enables the model to precisely pinpoint fault areas by identifying patterns and connections among system parts, concentrating on specific areas or nodes. In addition, a multi-linear perceptron block is designed to enhance the capturing of amplitude information and increase comprehension. The efficiency and generalizability of the proposed model are improved by the implementation of a multi-task training approach for locating faults and their type. With the use of two IEEE 13-Bus systems and the PSS/E 23-Bus system, the proposed fault diagnosis model is tested. Examining various setups for fault analysis allows for a more thorough evaluation of the model's ability to generalize and disturbance resilience. Experimental findings show that the proposed model outperforms existing cutting-edge techniques in terms of efficacy with a balanced accuracy of 0.8204 for classification, 0.556 for localization, and a Macro MAE of 38.780 for detection.

Dual-source gramian angular field method and its application on fault diagnosis of drilling pump fluid end

Under complex drilling working conditions, it is difficult to completely describe the working state of the drilling pump fluid end with a single-source signal to achieve a high fault diagnosis accuracy. This paper proposes to use dual-source signals (vibration signal and strain signal) to describe the working state of the fluid end. Especially, a dual-source gramian angular field (DS-GAF) method is proposed to fuse vibration-strain signals to provide more fault information. In DS-GAF method, the dual-source signal is converted to points in spherical coordinates, and the arccosine of the normalized amplitude of the two signals is assumed as the polar angle and the azimuthal angle, respectively. Three DS-GAF matrices are generated with the position of the points. These three matrices are respectively encoded as three colors (red, green, and blue) channels of the image to achieve signal fusion. A fault diagnosis method based on DS-GAF and ResNet for the drilling pump fluid end is proposed to improve the fault diagnosis accuracy under multiple working conditions. First, by the DS-GAF method, the vibration-strain signals of the fluid end are fused and converted into a fault diagnosis image dataset. Second, a fault diagnosis model based on ResNet is established and the effect of batch size on the performance of the fault diagnosis model is discussed. Finally, fault diagnosis experiments are carried out on the proposed fault diagnosis model and its performance is investigated. The results show that the diagnosis method proposed in this paper has the highest diagnostic accuracy of 98.97% for nine fault types under multiple operating conditions, with a maximum improvement of 18.91% compared to the original GAF method. The DS-GAF method for signal fusing proposed in this paper not only improves the accuracy of fluid end diagnosis, but also provides a reference for the signal-fusion diagnosis of other equipment.

Fault diagnosis model of main equipment in substation based on multi-mode time-frequency combination

The conventional fault diagnosis method of the main equipment in substations has strong limitations and the fault diagnosis accuracy is low, so this paper introduces the multi-mode time-frequency combination method and designs the fault diagnosis model of the main equipment in substations. First, the transmission mode of fault information of main transformer equipment is analyzed and the fault source is diagnosed. Secondly, the UHF partial discharge method is used to detect the partial discharge signal of the main substation equipment. On this basis, the main equipment fault diagnosis model of the substation is established based on the multi-mode time-frequency combination, and the equipment fault degree is obtained to complete the fault diagnosis. According to the experimental results, the proposed fault diagnosis model is highly feasible, and the accuracy of an insulation fault, overheating fault and discharge fault diagnosis is more than 98%.

Rotating machinery fault diagnosis using dimension expansion and AntisymNet lightweight convolutional neural network

Deep learning-based methods have made remarkable progress in the field of fault diagnosis for rotating machinery. However, convolutional neural networks are not suitable for industrial applications due to their large model size and high computational complexity. To address this limitation, this paper proposes the Antisym module and constructs AntisymNet, which is combined with dimension expansion algorithms for fault diagnosis of rotating machinery. To begin with, the original vibration signal of the rolling machinery is subjected to time-frequency transformations using the discrete Fourier transform and discrete wavelet transform. Subsequently, each transformed time-frequency signal is expanded in dimensions, resulting in two-dimensional matrix single channel images. These single channel images are then fused into RGB images to enhance the sample features. Finally, the proposed AntisymNet is utilized for recognizing and classifying the expanded signals. To evaluate the performance of AntisymNet, the MiniImageNet image dataset is employed as a benchmark, and a comparison is made with other state-of-the-art lightweight convolutional neural networks. Additionally, the effectiveness of the proposed fault diagnosis model is validated using the CWRU bearing dataset, Ottawa bearing dataset, and the hob dataset. The model achieves an impressive accuracy rate of 99.70% in the CWRU dataset, 99.26% in the Ottawa dataset, and an error rate of only 0.66% in the hob dataset. These results demonstrate the strong performance of the proposed fault diagnosis model.

A Dense ResNet Model with RGB Input Mapping for Cross-Domain Mechanical Fault Diagnosis

In actual engineering applications, the mechanical machine is exposed to uncertain conditions such as noise interference and various loads. The commonly used fault diagnosis models suffer degradation in the prediction accuracy in such complex industrial environments where the available label samples are insufficient and the conditions are varied. To combat this challenge, a cross-domain mechanical fault diagnosis method based on the deep-learning networks is proposed. It utilizes small samples, i.e., 10% of the total, and operates on the time-series signal collected from the mechanical equipment. It provides a classification accuracy of more than 97% on the dataset from Case Western Reserve University (CWRU) under variable conditions and 97.56% with the noise interference of 0 dB. The one-dimensional vibration signal is first converted into an image through RGB mapping. Then, the derived RGB image is capable of the time dependent and spatial properties of the time sequence signal and can be directly used as the input of the deep-learning networks. The deep-learning networks model, i.e., the ResNet, is adopted for the fault feature extraction and additional dense connections are added among the residual blocks to supplement the insufficient labeled samples within the networks. Then, an RGB-DResNet is constructed, capable of retaining the robust features for the classification of the mechanical faults in different working conditions. Finally, through retraining the model by use of transfer learning, the derived RGB-TDResNet model gives a fine adaption to the feature distribution with a small amount of target domain information. The performance of the proposed fault diagnosis model was validated on the dataset from CWRU. The results show that it provides a high identification accuracy and strong robustness in variable operating conditions as well as the noise environment. It is a rather promising approach for dealing with the cross-domain tasks of mechanical fault diagnosis.

A Mechanical Equipment Fault Diagnosis Model Based on TSK Fuzzy Broad Learning System

In an intelligent manufacturing context, the smooth operations of mechanical equipment in the production process of enterprises and timely fault diagnosis during operations have become increasingly important. However, the effect of traditional fault diagnosis depends on the feature extraction quality and experts’ empirical knowledge, which is inefficient and costly, and cannot match the needs of mechanical equipment fault diagnosis in intelligent manufacturing. The TSK fuzzy system has a strong approximation capability and the ability to interpret expert knowledge. The broad learning system (BLS) has strong feature extraction and fast computation capabilities. In this paper, we present a new model—the TSK fuzzy broad learning system (TSK-BLS). The model integrates the advantages of the BLS and the fuzzy system at the same time, which can be calculated quickly and accurately by pseudo-inverse and symmetry methods. On the other hand, the model is an embedded model-building mechanism, which extends the application scope of BLS theory. The model was tested on a bearing fault data set, provided by Case Western Reserve University, and the model’s fault diagnosis accuracy was as high as 0.9967. The results were compared with those of the convolutional neural network (CNN) and the BLS models, whose fault diagnosis accuracies are 0.6833 and 0.9133, respectively. Comparison showed that the proposed fault diagnosis model—TSK-BLS, achieved significant improvements.

Cross-domain intelligent fault diagnosis of rolling bearing based on distance metric transfer learning

Rolling bearings are present ubiquitously in mechanical equipment, timely fault diagnosis has great significance in guaranteeing the safety of mechanical operation. In real world industrial applications, the distribution of training dataset (source domain) and testing dataset (target domain) is often different and varies with operating environment, which may lead to performance degradation. In this study, a cross-domain fault diagnosis of rolling bearing method based on distance metric transfer learning (DMTL) and wavelet packet decomposition (WPD) is proposed. The Mahalanobis distance is adopted for learning the intrinsic similarity or dissimilarity between instances and learned by simultaneously maximizing the intra-class distances and minimizing the inter-class distances for target domain. The features of source domain and target domain are first extracted from original vibration signals by WPD which is a powerful tool in dealing with non-stationary signals and can provide meticulous analysis. Then, the DMTL model is adopted to eliminate the error propagation across different components, which can weaken the weight of low-quality instances and enhance the weight of high-quality samples. Finally, the k-nearest neighbor (KNN) classifier is applied to accomplish the cross-domain intelligent fault-type classification. The superiority and effectiveness of the proposed fault diagnosis model is validated by two diagnosis cases. The experimental results demonstrated that the proposed method performs better than other compared methods in recognizing various fault types and has the capability in handling the complex cross-domain adaptation scenarios.

CNN-Based Feature Fusion Motor Fault Diagnosis

Artificial intelligence fields have been using deep learning in recent years. Due to its powerful data mining capabilities, deep learning has a wide-ranging impact on the diagnosis of motor faults. A method for diagnosing motor faults based on the multi-feature fusion of convolutional neural network (CNN) is presented in this paper. As far as the method is concerned, CNN is used as the basic framework, and the CNN model has been improved. First, the collected vibration and current signals are preprocessed. Second, segmented multi-time window synchronous input is performed on the processed data. In addition, a multi-scale feature extraction process and time series fusion of vibration and current signals subject to synchronous input in the same time window can be performed, which ultimately enables the identification of motor faults with a high degree of accuracy. In order to verify the validity of the proposed fault diagnosis model, an experimental platform for fault simulation was built for the motor, and vibration and current signals of different motor states were collected and verified by experimentation. According to the results of the experiment, the method can effectively combine motor vibration and current signal fault features, and thus motor fault diagnosis can be improved. In comparison with a single signal input, a multi-signal input provides greater accuracy and stability. As compared to other multi-signal feature fusion methods, such a deep learning model is able to extract fault features in a more comprehensive manner, which helps to improve the accuracy of motor fault diagnosis.

Cycle temporal algorithm-based multivariate statistical methods for fault diagnosis in chemical processes

Multivariate statistical process monitoring methods are often used in chemical process fault diagnosis. In this article, (I) the cycle temporal algorithm (CTA) combined with the dynamic kernel principal component analysis (DKPCA) and the multiway dynamic kernel principal component analysis (MDKPCA) fault detection algorithms are proposed, which are used for continuous and batch process fault detections, respectively. In addition, (II) a fault variable identification model based on reconstructed-based contribution (RBC) model that paves the way for determining the cause of the fault are proposed. The proposed fault diagnosis model was applied to Tennessee Eastman (TE) process and penicillin fermentation process for fault diagnosis. And compare with other fault diagnosis methods. The results show that the proposed method has better detection effects than other methods. Finally, the reconstruction-based contribution (RBC) model method is used to accurately locate the root cause of the fault and determine the fault path.

Fault Diagnosis Method for Rolling Bearing Based on Sparse Principal Subspace Discriminant Analysis

Rolling bearings are omnipresent parts in industrial fields. To comprehensively reflect the status of rolling bearing and improve the classification accuracy, fusion information is widely used in various studies, which may result in high dimensionality, redundancy information of dataset, and time consumption. Thus, it is of crucial significance in extracting optimal features from high-dimensional and redundant feature space for classification. In this study, a fault diagnosis of rolling bearings model based on sparse principal subspace discriminant analysis is proposed. It extracts sparse discrimination information, meanwhile preserving the main energy of original dataset, and the sparse regularization term and sparse error term constrained by l2,1-norm are introduced to improve the performance of feature extraction and the robustness to noise and outliers. The multi-domain feature space involved a time domain, frequency domain, and time-frequency domain is first derived from the original vibration signals. Then, the intrinsic geometric features extracted by sparse principal subspace discriminant analysis are fed into a support vector machine classifier to recognize different operating conditions of bearings. The experimental results demonstrated that the feasibility and effectiveness of the proposed fault diagnosis model based on a sparse principal subspace discriminant analysis algorithm can achieve higher recognition accuracy than fisher discriminant analysis and its extensions, and it is relatively insensitive to the impact of noise and outliers owing to the sparse property.

A novel multivariate signal processing-based fault diagnosis approach of rotating machinery under various operating conditions

Compared with signals collected by the single sensor, the collected multivariate signals contain more information to reflect the state of mechanical equipment, which has a positive effect on fault diagnosis. However, different acquisition channels and various operating conditions interfere with the extraction of fault features of rotating machinery. To solve this problem, taking rolling bearings as an example in this paper, a novel method is adopted to alleviate these interferences and combined with an improved extreme learning machine (ELM) to achieve intelligent fault diagnosis of rolling bearings under various operating conditions. First, adaptive projection intrinsically transformed multivariate empirical mode decomposition is used to decompose multivariate signals and obtain intrinsic mode functions of each channel to construct feature matrices. Then, nuisance attribute projection (NAP) is employed to alleviate the interference components in the feature matrix, which are originated from different channels and operating conditions. Finally, vectors belonging to the processed feature matrix as samples are input into the proposed weighted extreme learning machine (WELM) for intelligent fault classification. The weighted matrix of the WELM can compress the dimension of the sample and extract sensitive features, and the effectiveness of the proposed fault diagnosis model via the above methods is verified by experiments. Furthermore, comparative experiments show that the proposed fault diagnosis model has higher accuracy than the model combined with NAP and traditional single-hidden layer feedforward neural network or ELM. Therefore, the proposed fault diagnosis model may potentially aid experts on fault diagnosis of rotating machinery under various operating conditions.

A fault diagnosis method for wind turbines with limited labeled data based on balanced joint adaptive network

Traditional machine learning or deep learning relies on a sufficient amount of labeled data for the training of fault diagnosis models. However, for new wind farms, insufficient data and limited labels hinder the establishment of such models. In order to cope with these two challenges, we proposed a new domain adaptive method for wind turbine fault diagnosis: balanced joint adaptive network (BJAN), which can transfer wind turbine data from other wind farms to the target new wind farm. In this method, we proposed a new pseudo-label prediction method that combines the sub-domain majority voting and overall iterations (SMV-I) to label the unlabeled data. In addition, BJAN uses long short-term memory model (LSTM) to replace common convolutional neural network (CNN) as the feature extraction module to improve diagnosis efficiency. Moreover, we also proposed a new distributed adaptive distance for BJAN: balanced joint maximum mean discrepancy (BJMMD), which can balance the data of different states during the distributed adaptive process to improve diagnostic accuracy. Numerical experiments with real wind turbine data in three wind farms not only show that the proposed SMV-I has excellent pseudo-label prediction performance, but also verify that the proposed fault diagnosis model BJAN has higher diagnostic accuracy and efficiency.

Fault diagnosis model for photovoltaic array using a dual-channels convolutional neural network with a feature selection structure

The effective fault diagnosis algorithm for the DC side photovoltaic (PV) array of a PV system (PVS) plays an important role in the operation efficiency and safety for PV power plants. But for fault diagnosis models it may fail to diagnose PV array (PVA) faults without detailed and quite fine fault features, especially line-line faults (LLF) occurring in the PVS that works under complex working conditions like low irradiance conditions and LLF with fault impedance. To address these challenges, this paper proposes a fault diagnosis scheme to diagnose different PVA faults using a proposed Dual-channel Convolutional Neural Network (DcCNN), which is able to automatically extract features and weight these features for fault classification. The important and fine features from the current and voltage electrical time series graph (ETSG) are extracted respectively by DcCNN in a double input way. Then, a proposed feature selection structure (FSS) is designed to improve the proposed fault diagnosis model capacity for diagnosing PVA faults under various conditions, including LLF, partial shading condition (PSC) and open circuit faults (OCF). Comparing to manually designed features, FSS not only helps DcCNN extract important features from PVA current and voltage automatically but also evaluates extracted features for further classification of DcCNN. Moreover, in the training stage, a proposed penalty is applied on DcCNN to constrain FSS, resulting in its sparse weight distribution. A comprehensive experiment based on a laboratory roof grid connected PVS is conducted. The results demonstrate the superior performance of the proposed approach compared with other algorithms as it can extract high-discriminative features from PVA current and voltage for different PVA faults, which is also effective on diagnosing LLF under low irradiance conditions and LLF with fault impedance.

Compressor fault diagnosis system based on PCA-PSO-LSSVM algorithm.

On the basis of the principal components analysis-particle swarm optimization-least squares support vector machine (PCA-PSO-LSSVM) algorithm, a fault diagnosis system is proposed for the compressor system. The relationship between the working principle of a compressor system, the fault phenomenon, and the root cause is analyzed. A fault diagnosis model is established based on the LSSVM optimized using PSO, the compressor fault diagnosis test experimental platform is used to obtain the fault signal of various fault occurrence states, and the PCA algorithm is employed to extract the characteristic data in the fault signal as input to the fault diagnosis model. The back-propagation neural network, the LSSVM algorithm, and the PSO-LSSVM algorithm are analyzed and compared with the proposed fault diagnosis model. Results show that the PCA-PSO-LSSVM fault diagnosis model has a maximum fault recognition efficiency that is 10.4% higher than the other three models, the test sample classification time is reduced by 0.025 s, the PCA algorithm can effectively reduce the input dimension, and the PSO-LSSVM fault diagnosis model based on the PCA algorithm for extracting features has a high recognition rate and accuracy. Therefore, the proposed fault diagnosis system can effectively identify the compressor fault and improve the efficiency of the compressor.

MILP-Based Fault Diagnosis Model in Active Power Distribution Networks

With a rapid growth in the deployment of renewable and distributed energy resources (DERs) in active power distribution networks, especially the inverter-interfaced distributed generators (IIDGs), existing fault section estimation methods are facing additional challenges. This paper proposes an optimization model for fault diagnoses in active power distribution systems, which aims at simultaneous identifications of suspected fault line sections and potential false alarms sent by remote fault indicators (RFIs). First, mathematical expressions of expected and false alarms of oriented RFIs (ORFIs) and non-oriented RFIs (NRFIs) are formulated to construct a basic fault diagnosis model. Minimizing the number of false alarms is chosen as the objective function to find the most credible one from all possible fault hypotheses which represent different combinations of elements in the outage area. Next, considering IIDGs, a modified fault diagnosis model is established by eliminating misleading components from the objective function which are produced by incompetent RFIs and have failed to detect weak currents. The monitoring data provided by distribution level phasor measurement units (D-PMUs) for weak IIDG fault currents are leveraged to construct the equivalent RFI current, which is compared with the trigger threshold to find incompetent sensors. The proposed problem is formulated as a mixed-integer linear programming (MILP) model, which is solved by off-the-shelf commercial solvers. The effectiveness of the proposed fault diagnosis model is validated by test cases representing several DERs and false alarms applied to a utility feeder.

A pairwise graph regularized constraint based on deep belief network for fault diagnosis

An enhanced intelligent fault diagnosis method is proposed based on pairwise graph regularized deep belief network (PG-DBN) model. In this novel framework, two different graph constraints are imposed on hidden layer of the Restricted Boltzmann Machine (RBM). The first graph constraint defines the representation of preserving the feature manifold structure in same class of the data and the second graph constraint defines the representation of the penalty of the feature manifold structure in different class of the data. The two graph constraints introduce feature manifold structure to RBM and make the extracted features contain more intrinsic information, which contributes to a better classification result. Meanwhile, the convergence and stability analysis of the proposed method is presented. Finally, the advantages of the proposed fault diagnosis model are evaluated by Tennessee Eastman process.

Quantum computing assisted deep learning for fault detection and diagnosis in industrial process systems

Quantum computing (QC) and deep learning techniques have attracted widespread attention in the recent years. This paper proposes QC-based deep learning methods for fault diagnosis that exploit their unique capabilities to overcome the computational challenges faced by conventional data-driven approaches performed on classical computers. Deep belief networks are integrated into the proposed fault diagnosis model and are used to extract features at different levels for normal and faulty process operations. The QC-based fault diagnosis model uses a quantum computing assisted generative training process followed by discriminative training to address the shortcomings of classical algorithms. To demonstrate its applicability and efficiency, the proposed fault diagnosis method is applied to process monitoring of continuous stirred tank reactor (CSTR) and Tennessee Eastman (TE) process. The proposed QC-based deep learning approach enjoys superior fault detection and diagnosis performance with obtained average fault detection rates of 79.2% and 99.39% for CSTR and TE process, respectively.

Particle Swarm Optimization-Support Vector Machine Model for Machinery Fault Diagnoses in High-Voltage Circuit Breakers

According to statistic data, machinery faults contribute to largest proportion of High-voltage circuit breaker failures, and traditional maintenance methods exist some disadvantages for that issue. Therefore, based on the wavelet packet decomposition approach and support vector machines, a new diagnosis model is proposed for such fault diagnoses in this study. The vibration eigenvalue extraction is analyzed through wavelet packet decomposition, and a four-layer support vector machine is constituted as a fault classifier. The Gaussian radial basis function is employed as the kernel function for the classifier. The penalty parameter c and kernel parameter δ of the support vector machine are vital for the diagnostic accuracy, and these parameters must be carefully predetermined. Thus, a particle swarm optimization-support vector machine model is developed in which the optimal parameters c and δ for the support vector machine in each layer are determined by the particle swarm algorithm. The validity of this fault diagnosis model is determined with a real dataset from the operation experiment. Moreover, comparative investigations of fault diagnosis experiments with a normal support vector machine and a particle swarm optimization back-propagation neural network are also implemented. The results indicate that the proposed fault diagnosis model yields better accuracy and efficiency than these other models.