Stator Inter-turn Short Circuit Research Articles

Analysis of the Impact of Stator Interturn Short-Circuit Faults on Induction Machines Driven by Direct Torque Control

This paper addresses the analysis of three-phase squirrel-cage induction machine (IM) with interturn short-circuit (ITSC) fault and its influence on direct torque control (DTC). The particularities of the DTC such as its behavior, its standard heuristic derivation, and its nature of been a nonlinear hysteresis-based predictive controller are exploited, thus allowing the improvement and development of alternative explanations to the phenomena. The understanding of DTC and the development of the current state–space model of the asymmetric IM, presented here for first time in the literature, enables the analytical treatment of the research topic and the discovery of several DTC reactions to the fault. The ITSC impact on DTC and its reaction leads to the following twofold characterizations: first, unobservable and visible effects, and second, compensation and tolerant reactions. For purposes of simulation, a plug-and-play configurable circuit-block for the asymmetric IM was developed based on Norton's equivalent circuit. Simulation and experimental results demonstrate the assertiveness of the developed analyses and theoretical findings, which allows future research in online fault diagnostics and condition monitoring of inverter-fed IM with this type of fault.

Effect of Voltage Unbalance and Stator InterTurn Short Circuit on the Characteristic of Three Phase Induction Motor

Effect of Voltage Unbalance and Stator InterTurn Short Circuit on the Characteristic of Three Phase Induction Motor

Information Fusion With Belief Functions for Detection of Interturn Short-Circuit Faults in Electrical Machines Using External Flux Sensors

This paper proposes a diagnosis method that exploits the information delivered by external flux sensors placed in the vicinity of rotating electrical machines, in order to detect a stator interturn short circuit. This fault induces a dissymmetry in the external magnetic field that can be measured by the sensors. Sensitive harmonics are extracted from the signals delivered by a pair of sensors placed at 180° from each other around the machine, and data obtained for several sensor positions are analyzed by fusion techniques using the belief function theory. The diagnosis method is applied on induction and synchronous machines with artificial stator faults. It will be shown that one can obtain high probability to detect the fault using the proposed fusion technique: on various series of measurements, the proposed approach has obtained a 90% detection rate on a considered machine.

Discrimination between Supply Unbalance and Stator Short-Circuit of an Induction Motor Using Neural Network

The objective of this paper is to investigate the contribution and effectiveness of the use of a Neural Network (NN) Multi-Layer Perceptron (MLP) of feed-forward type technique to discriminate between the Supply Voltage Unbalance (SVU) and the stator Inter Turn Short-Circuit (ITSC) of an induction motor. The proposed approach in this paper is based on the exploitation of any useful information existing in both the current and the voltage quantities simultaneously provided by the various instantaneous powers such as the active and the reactive powers as well as the power factor. The merits of the proposed approach using the NN technique as an effective solution to the problem of discrimination is assessed by a simulation work and then validated by an experimental work conducted by the Diagnosis Group of the LDEE Laboratory.

Three Phase Induction Motor's Stator Turns Fault Analysis Based on Artificial Intelligence

This article presents a method for fault detection and diagnosis of stator inter-turn short circuit in three phase induction machines. The technique is based on modelling the motor in the dq frame for both health and fault cases to facilitate recognition of motor current. Using an Adaptive Neuro-Fuzzy Inference System (ANFIS) to provide an efficient fault diagnosis tool. An artificial intelligence network determines the fault severity values using the stator current history. The performance of the developed fault analysis method is investigated using Matlab/Simulink® software. Stator turns faults are detected through current monitoring of a 2 Hp three phase induction motor under various loading conditions. Fault history is calculated under various loading conditions, and a wide range of fault severity.

Rotor/Stator Inter-Turn Short Circuit Fault Detection for Saturable Wound-Rotor Induction Machine by Modified Magnetic Equivalent Circuit Approach

This paper presents a new method to model healthy and faulty wound-rotor induction machines (WRIMs) with and without inter-turn short circuit fault by a single set of equations. The model is presented for a machine with arbitrary pole, and rotor and stator slot numbers. A single set of equations, including both electric and magnetic parts, is solved to obtain full dynamic behavior of the machine. Therefore, the modified magnetic equivalent circuit with non-linear elements is used for modeling and a numerical technique is employed to solve the non-linear equations. The proposed modified method has a simple calculation procedure in comparison with the conventional magnetic equivalent circuit method. Solving the electric and magnetic equations by a single set of equations is the main advantage of the presented method, which is proposed for a WRIM machine, for the first time. In addition, to increase the accuracy, the saturation phenomenon is also considered in the model. Due to the saturation effect, there are some non-linear algebraic magnetic equations, which should be simultaneously solved with differential equations. A trapezoidal technique is used to convert differential equations to algebraic ones. To solve the non-linear equations, non-linear equations, Newton Newton–Raphson method is employed. Current signature analysis is used for rotor and stator inter-turn short circuit fault detection. Finally, the finite-element method is used to verify the effectiveness of the proposed modeling method. It is worth noting that the proposed method can model a healthy and faulty machine with different faults by a single model.

Fault Diagnostic of Doubly-Fed Induction Generator in Stator Inter-Turn Short Circuit Based Wind Turbine

This paper describes a Fault Tolerant Control (FTC) of a doubly-fed induction generator (DFIG) based wind turbine model suitable for the simulation of this generator in the mode faulty mode. The dynamic model of a DFIG with stator inter-turn short circuit fault is proposed. A model (abc) is developed, which can represent both the healthy and faulty conditions. The DFIG is directly connected to the grid whereas the rotor winding is fed by back-to-back PWM converters .the Control schemes for active and reactive power regulation are designed firstly. Under different wind speed, maximum power point tracing (MPPT) control is implemented to ensure the optimum active power output. The numerical simulation developed in Matlab/Simulink studies the effects of stator inter-turn short-circuit in the DFIG. Afterward, the application of Approach technique of Adaptive Obs

Impact of Inter-Turn Short-Circuit Location on Induction Machines Parameters Through FE Computations

This paper studies the effect of the location of stator inter-turn short-circuit (ITSC) faults on the squirrel-cage induction machine (IM) model parameter's. The ITSC location can be affected in three different ways, however we studied two of them: the physical placement for a fixed number of turns fault and the variation of the number of turns short-circuited. Both different cases will influence the rotating magnetic field shape in the air gap and thus the stator and rotor parameters. Two investigations are conducted, the former one is a finite element analysis (FEA) of the four location cases of equal severity factor ITSC in the IM phase “a.” The latter is a theoretical and mathematical analysis, where the ITSC is modeled by a step-down auto-transformer in the faulty circuit. The results of the FEA corroborate that different locations impact the IM parameters. However, the effect is not substantial and the theoretical model indicates how the parameters vary with the fault. Moreover, a comparative study of two IM damaged models that present different approach to the stator leakage inductance is performed. The asymmetric mathematical model is presented, simulated, and experimentally compared.

Modeling and stator Inter‐Turn short circuit fault detection for saturable salient pole synchronous machine by a non‐linear magnetic equivalent circuit approach

AbstractThis paper presents a novel and adequate model for healthy and faulty salient pole synchronous machines with and without interturn short circuit fault. The model is presented for a machine with arbitrary pole numbers, arbitrary damper bars, and stator slot numbers. The magnetic equivalent circuit with nonlinear elements is used for modeling, and numerical techniques based on Newton‐Raphson method have been approved for solving of nonlinear equations. Because the design of electric machines is based on the knee point of a B‐H curve, consideration of saturation effect is mandatory for adequate studying. Because of the saturation effect, there are some nonlinear algebraic magnetic equations, which should be solved simultaneously with differential equations. Trapezoidal technique is used for differential equations converting to algebraic type, and Newton‐Raphson method is used for a nonlinear set equation solving. Stator current signature analysis is used for stator interturn short circuit fault detection. Finally, obtained results by finite element method are used to verify the effectiveness of the proposed modeling method. The proposed approach for magnetic equations based on nodal potential and reluctance mesh model equations is one of the paper novelties for the salient pole synchronous machine modeling in both healthy and faulty cases. This dynamic modeling method has less complexity compared to finite element method and pure nodal potential approaches. Solving the electric and magnetic equations by a single set of equations is the main advantage of the presented method, which has been addressed for a salient pole synchronous machine for the first time. Another advantage of the proposed study is the capability of modeling the healthy and faulty machine with interturn fault by a single model.

Torque ripple reduction in a surface permanent magnet synchronous machine with stator inter-turn short circuit

Torque ripple reduction in a surface permanent magnet synchronous machine with stator inter-turn short circuit

Analysis on Steady-State Electromagnetic Characteristics and Online Monitoring Method of Stator Inter-Turn Short Circuit of Turbo-Generator

The intent of this paper is to find out significant united electromechanical characteristics for online monitoring of stator interturn short circuit (SISC) faults. Different from other studies, this paper pays attention to neither the stator voltage and current, nor the winding inductance variation, but focuses on the faulty electromagnetic characteristics including the exciting current, the circulating current in the parallel branches (CCPB), and the electromagnetic torque (EMT). The simulation work is modeled for a QFSN-600-2YHG type turbo-generator and the experiment is taken on a MJF-30-6 fault-simulating generator to verify the theoretical analysis. The simulation result and the experiment data accord with the theoretical analysis and show that, as SISC occurs, second harmonics will be induced in the exciting current, first and third harmonics will be induced in the CCPB, and second and fourth harmonics will be produced in the EMT. Moreover, the corresponding time-domain waves will also fluctuate intensely, while the mean value of the exciting current and the EMT will be decreased. As SISC develops, the harmonic increment, the fluctuation intensity of the time waves, and the decreased rate of the mean value will be also increased. These united characteristics can be applied to the fault diagnosis and online monitoring on SISC fault.

Induction Motors Stator Fault Analysis based on Artificial Intelligence

This article presents a method for fault detection and diagnosis of stator inter-turn short circuit in three phase induction machines. The technique is based on the stator current and modelling in the dq frame using an Adaptive Neuro-Fuzzy artificial intelligence approach. The developed fault analysis method is illustrated using MATLAB simulations. The obtained results are promising based on the new fault detection approach.

Vibro-acoustic behaviour of an induction machine with stator inter-turn short-circuit

This paper focuses on the calculation of noise and vibrations due to electromagnetic forces in rotating electrical machines in faulty conditions. The effects of a stator inter turn short circuit is analysed through an analytical model. Theoretical results give the radial forces and explain the reasons behind the noise and vibrations. They also show how inter-turn-short-circuit is responsible for additional low-mode forces, generating noise and vibrations increase. Experimental measurements are carried out to validate the theoretical results.

EFFECT OF STATIC ECCENTRICITY AND STATOR INTER-TURN SHORT CIRCUIT COMPOSITE FAULT ON ROTOR VIBRATION CHARACTERISTICS OF GENERATOR

This paper investigates the radial rotor vibration characteristics under static air-gap eccentricity and stator inter-turn short circuit composite faults. The air-gap magnetic flux density is firstly deduced to obtain the unbalanced magnetic pull (UMP) on rotor. Then the rotor vibration characters, as well as the developing trend between the faulty parameters and the vibration amplitudes, are analyzed. Finally, the experiments are taken on a SDF-9 type simulating generator. It is shown that the radial deformation possibility, the 2nd, 4th, and 6th harmonic vibrations will be caused by the composite faults. Besides, the development of the inter-turn short circuit, the increment of the static eccentricity, and the rise of the exciting current will all get the deformation trend and the vibration amplitudes increased.

Application of morphological max-lifting scheme for identification of induction motor stator inter-turn short circuit

Application of morphological max-lifting scheme for identification of induction motor stator inter-turn short circuit

Fault Analysis of Stator Inter-Turn Short Circuit in Doubly Fed Induction Machines

The doubly fed induction generator (DFIG) is an important component of wind turbine systems,so the fault analysis is great necessary.This paper shows a way to analysis the features of stator inter-short circuit fault,which is based on multi-circuit theory.The fault features of stator inter-turn short circuit in doubly fed induction are analyzed in this paper,deeply and thoroughly.Then a multi-loop model was carried out to simulate 5.5kW DFIG ,which was in normal conditions and in cases of fault of stator inter-turn short circuit,respectively.A fourier transformation was applied to analysis the simulation results,especially about short circuit current.

The Zero-Sequence Current as a Generalized Diagnostic Mean in Δ-Connected Three-Phase Induction Motors

In this paper, a new diagnostic mean is introduced for accurate, reliable, and effective diagnosis of faults in delta-connected induction motors. This mean is the zero-sequence stator current spectrum. The study is carried out with analytical calculations and finite-element method simulations. Most common faults are examined for a 4-kW cage induction motor. The analysis will reveal that the proposed mean is able to successfully identify the static eccentricity fault, even in induction motors which produce principal slot harmonics, the broken bar fault, the unbalanced voltage supply, and the stator interturn short-circuit. It will also be shown that through the proposed method, it is possible to distinguish the interturn short-circuit from the unbalanced voltage supply.

A New Approach to Fault Diagnostics for Permanent Magnet Synchronous Machines Using Electromagnetic Signature Analysis

This paper proposes a novel approach to health monitoring and multifault detection in permanent magnet synchronous machines using direct flux measurement with search coils. Unlike other spectrum-based fault detection schemes, only the fundamental frequency component of the measured voltage is utilized for fault detection. Therefore, the performance of the proposed scheme is not affected by nonstationary speed or harmonics introduced by the power supply. In addition, location of interturn short circuits and direction of static eccentricity can be detected, which have never been done by any other scheme. In spite of the invasive nature of the technique, it is very suitable for mission-critical applications and emerging applications such as off-shore wind turbines, hybrid vehicle technology, and military applications, where early detection of faults is of paramount importance. 2-D simulations using finite element analysis have been presented to validate the proposed method under different operating conditions. Experimental introduction of stator interturn short circuit, demagnetization, and static eccentricity has been discussed, and the proposed scheme is experimentally implemented to examine its effectiveness.

Detection and Analysis of Stator Winding Inter-Turn Short Circuit Fault in Permanent Magnet Linear Synchronous Motor

A two-dimensional finite element model of PMLSM is build based on the finite element analysis software Magnet to research the diagnosis of stator winding inter-turn short circuit fault in PMLSM. The velocity, thrust, the stator current performance curve are obtained by simulation using Magnet when PMLSM is normal and under different extent inter-turn short circuit fault, the harmonic content of speed and thrust are analyzed using Matlab / Simulink , the conclusion that the thrust of the harmonic content is used as the Permanent Magnet Linear Synchronous Motor (PMLSM) stator inter-turn short circuit fault feature is proposed , which provided a basis for detection of stator winding inter-turn short circuit fault in PMLSM.

Modelling and Fault Diagnosis of Stator Inter-Turn Short Circuit in Doubly Fed Induction Generators

AbstractIn this paper, a dynamic state space model of a DFIG with stator inter-turn short circuit fault is proposed. This model can quantitatively describe the fault at any level in any single phase. Both healthy and faulty conditions can be simulated by using this model. Base on this model, an observer based fault detection and diagnosis (FDD) scheme is developed, which can not only provide a rapid detection when fault occurs but also give an accurate diagnosis of the fault position and level. In order to ensure the observer stability under a wide rang of the speed variation of DFIGs, a time varying Kalman like gain supplied with measured rotor speed is applied to the observers. Moreover, an exponential adaptive observer is employed to provide a desirable estimation of fault level. The simulation results demonstrate the effectiveness of this approach in detecting and diagnosing the faults under both stationary and speed varying operations. The latter is particularly important for fault detection of wind turbine DFIGs.