Fault diagnosis of single-phase induction motor based on acoustic signals

Acoustic based fault diagnosis of three-phase induction motor

A hybrid deep-learning model for fault diagnosis of rolling bearings

As an important part of power system, power transformer plays an irreplaceable role in the process of power transmission. Diagnosis of transformer’s failure is of significance to maintain its safe and stable operation. Frequency response analysis (FRA) has been widely accepted as an effective tool for winding deformation fault diagnosis, which is one of the common failures for power transformers. However, there is no standard and reliable code for FRA interpretation as so far. In this paper, support vector machine (SVM) is combined with FRA to diagnose transformer faults. Furthermore, advanced optimization algorithms are also applied to improve the performance of models. A series of winding fault emulating experiments were carried out on an actual model transformer, the key features are extracted from measured FRA data, and the diagnostic model is trained and obtained, to arrive at an outcome for classifying the fault types and degrees of winding deformation faults with satisfactory accuracy. The diagnostic results indicate that this method has potential to be an intelligent, standardized, accurate and powerful tool.

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Classifying Transformer Winding Deformation Fault Types and Degrees Using FRA Based on Support Vector Machine

The paper deals with the identification of the furnace power transformer state. The furnace transformer was subjected to several prophylactic measurements. Their results are summarized and described in the article. In spite of that it is not a standard power oil transformer there was selected appropriate procedures and practices with respect to international standards. Identified failure was confirmed by the disassembly of the transformer in Repair Company.

Identification failure of 3 MVA furnace transformer

Abstract The authors describe experimental and theoretical analyses of faults of power transformer winding. Faults were caused by mechanical effect of short-circuit currents. Measurements of transformer were carried out in high-voltage laboratory. Frequency and time diagnostic methods (method SFRA - Sweep Frequency Response Analysis, impact test) were used for the analyses. Coils of transformer windings were diagnosed by means of the SFRA method and the time impact test. The analyzed methods had a significant sensitivity to a relatively small deformation of coil. In the analysis a new technique for analyzing the effects of short-circuit currents is introduced. This technique is developed for high-voltage transformers (different types of power). The proposed analyses show that it is necessary to analyze the value of short-circuit current. Short-circuit current represents a danger for the operation of the power transformer. The proposed approach can be used for other types of transformers. Moreover, the presented techniques have a potential application for fault diagnosis of electrical equipment such as: transformers and electrical machines.

/pdf/frequency-and-time-fault-diagnosis-methods-of-power-4150rqoglj.pdf

Frequency and time fault diagnosis methods of power transformers

The paper presents theoretical and experimental analyses of a possible effect of the short-circuit forces on the transformer winding. The first part of the paper is focused on creation and activity of the radial and axial forces during a short circuit. It shows dimensions, direction and − of course − the resulting mechanical stress. The presented equation shows basic dependencies of these mechanical forces created in the transformer winding. Finally, the paper presents experimental methods of diagnosing and analysing the effects of short-circuit forces on the transformer winding.

/pdf/measurement-of-short-circuit-effects-on-transformer-winding-3h1tgovzvd.pdf

Measurement of Short-Circuit Effects on Transformer Winding with SFRA Method and Impact Test

Paper deals with the analysis of thermal processes in oil power transformers. By means of the mathematical analysis and experimental measurements it is possible to diagnose of distribution oil transformers in terms of mechanical strength of winding. Analysis of warming at varying loads is very importance, since allows determining the load capacity and overload of the transformer under various operating conditions and respecting the variable ambient temperature.

Thermal processes in materials of oil transformers

This article presents electromagnetic effects on transformer winding. It shows dimension of force causing by short-circuits and how this force is created. In graphs are shown basics dependences for transformer and its dimension (its power) and mechanical forces. In the next is dealing with transient actions at overvoltages. There is showed how can overvoltages be created and how long overvoltages are take time. Third part of article is focused on measurement method. This method is preferred for testing big transformer. In method are described frequency ranges and possible exploitation of this method. Conclusion is proposal for next leading of this issue.

Analysis of Transformer Winding considering Transient Effects

Article presents analysis of insulating and mechanical state of transformers considering possible effect of short-circuit currents on the winding. The first part of the article is focused to negative activity thermal and mechanical effects of short-circuit currents. The last part of the article is focused to the simulation method which shows the mechanical stress caused by the short circuit-currents. Finally, the article presents experimental frequency methods of diagnostics for analysis of the short-circuit effects on insulating and mechanical transformer state.

http://ieeexplore.ieee.org/iel7/7604847/7736463/07736498.pdf

Richard Janura

Papers

Frequency and time fault diagnosis methods of power transformers

Measurement of Short-Circuit Effects on Transformer Winding with SFRA Method and Impact Test

Thermal processes in materials of oil transformers

Analysis of Transformer Winding considering Transient Effects

Analysis of short-circuit effects on transformer state by frequency method