Fault Detection in Three Phase Induction Motor using Artificial Intelligence: A review P.D.Duhat , C.A.Kshirsagar Dept. of Electronics & Power, Dept. of Electronics & Telecomm, Amaravati University B.N.C.O.E,Pusad(India) pdduhat@rediffmail.com chanchal.kshirsagar@gmail.com Abstract— This paper describes a overview of induction motors signature analysis as medium for fault detection, as well it describes a generalized model of the three phase induction motor using matlab simulink. This paper aims at developing mat lab based machine model with neuro fuzzy techniques for detecting the faults of induction motor. Keywords- neurofuzzy technique, motor signature analysis, simulink model, neural network, induction motor I. INTRODUCTION Induction motor are used in many fields of industrial production system, due to their advantages like quick start, less maintenance etc. Long term working failure is very crucial for production system. Like other types of electrical machines these motors are exposed to a wide variety of environmental conditions electrical and mechanical errors. Because of these motor defects will bring about labour and maintenance cost. Motor operating life is reduce if these faults left undetected. In addition, it causes delay of production process and financial losses , due to stopping of motor. Therefore, it is always desirable to provide prevention of motor failure rather than protection. This is achieved by continuous condition monitoring. It avoids unexpected failure of a critical system. Hence, there is a considerable demand for electrical machines and drive system with fault diagnostics and prediction features. Before studying fault diagnostic methods, it is necessary to know the most common faults found in induction motor . The faults occur in a motor depends upon construction and working conditions, it has two main parts stator and rotor, thus faults are classified according to their location that is in stator part or in rotor parts. These faults are classified as follows: Stator Faults: 1) Abnormal connection of the stator winding 2) Turn to ground faults 3) Opening or shorting of the stator winding 4) Stator core related faults Rotor Faults: 1) Rotor winding related fault 2) Bearing and gear box faults 3) Eccentricity related faults 4) Broken rotor bar fault While detecting the above mentioned faults in an induction motor many parameters are taken into consideration such as temperature, vibration, noise, supply voltage, current and load etc. The main causes of stator core failure are as follows: 1) Core end region heating resulting from axial flux in the end winding region. 2) Core melting caused by ground faults currents. 3) Manufacturing defects in laminations 4) Inter laminar insulation failure. 5) Stator rotor rubs during assembly and operation. Rotor faults: The most common rotor faults in an induction motor may be classified as: 1) Rotor winding related faults 2) Broken rotor bar faults 3) Bearing and gearbox faults 4) Eccentricity related There are some parameters of motor which are affect when faults occur in a rotor such as short circuit turns in rotor windings cause operational problems that is a vibration levels. Bearing fault may account for 42 – 50% of all motor failure. The bearing fault may lead to excessive audible noise, uneven running, reduced working accuracy and increased vibration. Eccentricity is a condition of the asymmetric air gap between stator and rotor , eccentricity develops high unbalanced radial forces ,vibrations and noise in the motor. Thus each occurred faults will produce some uneven parameters of the motor such as vibration, noise, unbalanced voltage etc. Thus by condition monitoring we can identify the actual fault occurred. II LITERATURE REVIEW There are fault monitoring techniques such as Invasive and Non-invasive methods .These can be explained as model based technique, signal processing technique, AI based techniques etc. A. Model Based Technique : This technique is categorized into invasive method by using the actuators and sensors the task consist of the different measurable signals. These measurable signal consist of some dependencies. These signal dependencies are expressed by mathematical model. Issermann [12] has presented a unified model based fault detection and prediction (FDP) techniques. Based on the measured signal the detection model generates residuals, parameter estimation or state estimates which are called features. By comparing these measured features with the normal features, the changed features are detected leading to analytical symptoms. This technique is developed for non – linear multiple input multiple output discrete time system. The stability of the fault detection and prediction scheme enhances the detection and time to failure accuracy. The main disadvantage of these methods is it requires accuracy while building mathematical model so more time spent for building the model, possibly more complex design procedure. B. Signal Processing Technique: This is also known as non –invasive method. The faults in induction motor are detected by using stator current analysis. The above proposed system was able to diagnosis of induction motor faults such as breakage of rotor bar, air gap eccentricity , bearing faults, fault in stator winding etc. this method also be applied on line[2],[1]. As in [3] some of the main stator current signature depending upon the frequency analysis is: Classical (FFT) fast Fourier transform techniques are applied to the measured sensor signals in order to generate features or parameters. As in [4] instantaneous power FFT in which instantaneous power is used as a medium for motor signature analysis. However the power spectra are still noisy. Bispectrum is term of the two dimensional Fourier transform of the third order sequence of process, this preserves both magnitude and phase information. The technique should be particularly applied to detect electrical based faults. High resolution spectral analysis based on Eigen analysis of the autocorrelation matrix in the digital signal, that is keep only the principle spectral components of signal and to decrease noise. With the above analysis wavelet and short time Fourier techniques (STFT) are used which analyse small sections of the signal at a time. Park’s vector analysis in [2] based on the locus of the instantaneous spatial vector sum of three stator currents that allows the detection of faulty condition by monitoring the deviation of the acquired pattern. Results obtained by the parks vector approach are more discriminative than those obtained by traditional FFT based MCSA. The above conventional methods are expensive to realize are unsuitable for online implementation, require the knowledge of an expert or utilize a rigorous mathematical model. To overcome this problem, soft computing techniques such as artificial intelligence, artificial neural network (ANN), fuzzy system etc. have been employed to build model based fault detection technique. C. Soft Computing Techniques These are the non-invasive measurement technique which are inexpensive and as in [6] ANN is proposed for fault detection and identification, it can be used as computational model of the brain. As in [7] has suggested a neural network approach for the detection and location automatically of an inter turn short circuit fault in the stator windings of an induction motor. a multilayer feed forward neural network along with back propagation algorithm are used to train the neurons. Neural network is the computational model which cannot provide the heuristic interpretation of the solution. The neural network with fuzzy logic principle enables the neurofuzzy system to provide more accurate fault detection and knowledge behind the fault detection. In [11] induction motor have been applied an adaptive neural fuzzy inference system for detection of inter turn insulation and bearing wear faults. it proved here that ANFIS technique provide more accurate results. As in [10] fuzzy logic methodology used for detection of stator winding fault in induction motor. The fuzzy logic method able to detect the motor condition with high accuracy for both noise and without noise. The stator current three phase rms values have been used as the input to the fuzzy logic system. The drawback of this method is a current unbalanced originating from the supply source may be identified as a faulty condition of the motor. In [7] generalized feed forward neural network is used for fault detection the number of input processing elements are equal to that of number of statistical parameters. Minimum thirteen parameters are calculated with RMS value of zero mean signals. These parameters are classifying under four conditions to developed generalized feed forward neural network. In [8] support vector machine are learning machines that are able to avoid the curse of dimensionality in both computation and generalization. Various fault of induction motor are detected using SVM to classify different faults, the statistical parameters are calculated from current data. These statistical parameters are RMS value of zero mean signal, maximum and minimum values that is skewness coefficient and kurtosis coefficient. Here SVM is used for non linear mapping to generate classification feature from the original data. The SVM classification task consist of selection of kernel function. It consist of RBF, Linear, and MLP kernals which are tested using matlab. Thus total data which includes thirteen input features is divided into three groups. These three groups classified as healthy and faulty groups with various fault identification class. The classification accuracy is influenced by the percentage of data tagged for training and testing. In previous studies various methods are used to detect the faults in induction motor from above review the various faults of motor can be diagnosed. The various techniques can be implemented by overcome the drawback of the previous one. The most suitable technique now a days used are AI techniques. To give better performance of AI technique, these can be used with signal processing technique which are also called Hybrid technique. In this paper matlab simulink software is very useful to implement these techniques. This will help to design precise model of induction motor. This model is of practical use which can be provided with AI system this can trained to model the general behaviour of a class motor. In the proposed work these techniques are explained. III PROPOSED WORK IV DISCUSSION As in [9]y.k.wong has given the modeling of three phase induction motor using MATLAB simulink. This modeling of motor is done on the basis of d-q machine model theory. Simulink model is helpful for faulty data generation, so as numerical data is generated for training the artificial intelligence for normal as wel as faulty condition. But still this dynamic model simulation requires expertise for mathematical simulation of this d-q model. In this paper matlab simulink model is used. Instead of experimental data the training data is generated by this simulation model that is constructed using the information found on nameplate of the motor.[5] This simulink model uses neural network and nerofuzzy system to train the artificial intelligence for healthy and faulty condition of the motor. This simulink motor model provided with stator current, voltage, speed, torque as input. This input parameters are provided in terms of three cases. Case1 – here input parameter of the motor is under the consideration of no load for standard condition that is given on the name plate of the motor. Second case – is the same input parameters under half load condition. Third case is for full load condition. After applying this input parameter case by case we are taking the output from the simulink motor model, this output from model are stator current (I), voltage (V), speed (N), and torque (T). For first case the output parameter will also gives standard output as per name plate of motor. But for second case and third case there must be fault will be occur. But for training the ANN the selection of the best inputs and making structure compact feature extraction is important. This feature extraction at different condition that is no load, half load, full load to collect data. Before this the output from motor model processed with the FFT algorithm, so as the best input data is made. The data generated from feature extraction process is used for training the ANN. The same process is done for faulty data that is for second and third case condition. When the ANN trained properly it will provide normal and faulty decision. This set up can be test using experimental data of the induction motor. The experimental data is provided as input to this set up and depending on this input it will provide the decision whether the motor is normal or faulty. The motor used for the following method is 5HP, 440V,1450 rpm. The matlab simulink based motor model is proposed. The proposed model uses neural network and ANFIS network. So as to detect the fault for minimum experimental data. The proposed model will also compare the result from neural network and ANFIS. This model will reduce amount of experimental data that are needed to design fault detector. The proposed model is shown as follows: DSP Processor (FFT, WT) Training Set up of Induction Motor Data Generation (Feature Extraction) ANN (Neural network, ANFIS) Testing Set up of Induction Motor I DSP Processor (FFT, WT) Data Generation (Feature Extraction) REFERENCES [1] Prof. Kalpesh J Chudasama, Dr. vipul shah, “Induction motor Noninvasive fault diagnosis techniques : A Review,” , International journal of reaserch & technology,ISSN 2278-0181 [2] M A karand S.Billal,Hiralal M.Suryawanshi and Mahesh K.Mishra,”Detection of Incipient Faults In Induction Motor using FIS, ANN, ANFIS Techniques,” JPE8-2-9,vol.8,2 April 2008. [3] Mohamed EL Hachemi Benbouzid, senior Member IEEE,” A Review of Induction Motors Signature Analysis as a Medium for Faults Detection,” , IEEE transaction on industrial electronics vol. no. 47,October 2000. 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