A comparison of techniques for fault detection in inverter-fed induction motors in transient regime

"(c) 2017 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works."[EN] Fault detection in induction motors operating in non-stationary regimes has become a need in today's industry. Most of the works published deal with line-fed motors. Nevertheless, the number of inverterfed induction motors has significantly increased in recent years. Therefore, several fault detection techniques have been proposed lately for this type of motors, based mainly on an adequate input signal processing to obtain fault signatures in the time-frequency domain. In this paper, a comparison of time-frequency techniques applied to fault detection in inverter-fed induction motors in a transient state is presented. For that purpose, the techniques are applied to two current signals acquired from two induction motors with two types of faults: bar breakage and mixed eccentricity. The paper shows the particularities and special difficulties of diagnosing under this type of feeding, reviewing the works related to each technique. The strengths and weaknesses of these techniques are discussed with the goal of providing a criterion for its application in an industrial environment and guidance for future developments in this field.This work was supported in part by the Spanish Ministerio de Economia y Competitividad and in part by the FEDER program in the framework of the Proyectos I+D del Subprograma de Generacion de Conocimiento, Programa Estatal de Fomento de la Investigacion Cientifica y Tecnica de Excelencia under Grant DPI2014-52842-P.Fernandez-Cavero, V.; Morinigo-Sotelo, D.; Duque-Perez, O.; Pons Llinares, J. (2017). A comparison of techniques for fault detection in inverter-fed induction motors in transient regime. IEEE Access. 5:8048-8063. https://doi.org/10.1109/ACCESS.2017.2702643S80488063

Detection of Broken Rotor Bars in Nonlinear Startups of Inverter-Fed Induction Motors

[EN] Fault detection in induction motors powered by inverters operating in nonstationary regimes remains a challenge. The trajectory in the time-frequency plane of harmonics related to broken rotor bar develops very in proximity to the path described by the fundamental component. In addition, their energy is much lower than the amplitude of the first harmonic. These two characteristics make it challenging to observe them. The Dragon Transform (DT), here presented, is developed to overcome the described problem. In this article, the DT is assessed with nonlinear inverter-fed startups, where its high time and frequency resolutions facilitate the monitoring of fault harmonics even with highly adjacent trajectories to the first harmonic path.Fernández-Cavero, V.; Pons Llinares, J.; Duque-Perez, O.; Morinigo-Sotelo, D. (2021). Detection of Broken Rotor Bars in Nonlinear Startups of Inverter-Fed Induction Motors. IEEE Transactions on Industry Applications. 57(3):2559-2568. https://doi.org/10.1109/TIA.2021.30663172559256857

Diagnosis of Broken Rotor Bars during the Startup of Inverter-Fed Induction Motors Using the Dragon Transform and Functional ANOVA

[EN] A proper diagnosis of the state of an induction motor is of great interest to industry given the great importance of the extended use of this motor. Presently, the use of this motor driven by a frequency converter is very widespread. However, operation by means of an inverter introduces certain difficulties for a correct diagnosis, which results in a signal with higher harmonic content and noise level, which makes it difficult to perform a correct diagnosis. To solve these problems, this article proposes the use of a time-frequency technique known as Dragon Transform together with the functional ANOVA statistical technique to carry out a proper diagnosis of the state of the motor by working directly with the curves obtained from the application of the transform. A case study is presented showing the good results obtained by applying the methodology in which the state of the rotor bars of an inverter-fed motor is diagnosed considering three failure states and operating at different load levels.This research has been partially funded by the University of Valladolid.Fernández-Cavero, V.; García-Escudero, LA.; Pons Llinares, J.; Fernández-Temprano, MA.; Duque-Perez, O.; Morinigo-Sotelo, D. (2021). Diagnosis of Broken Rotor Bars during the Startup of Inverter-Fed Induction Motors Using the Dragon Transform and Functional ANOVA. Applied Sciences. 11(9):1-12. https://doi.org/10.3390/app1109376911211

Depression and associated factors in people living with HIV/AIDS in Quindio, Colombia, 2015

Introduction: Antiretroviral Therapy has been an effective response to HIV infection, however, some psychological variables can interfere with adaptation to treatment and quality of life of patients because this is a chronic disease. Objective: To identify indicators of depression and associated factors in a group of people living with HIV / AIDS in Quindio, Colombia. Material and Methods: A cross-sectional study was performed in a group of 70 adults diagnosed with HIV were receiving antiretroviral treatment in Quindio, Colombia. The information was obtained through questionnaires Beck´s depression and anxiety, the questionnaire MOS social support and a survey on socio-demographic information, family and health aspects. Results: The average age stood at 38,2 years old; (DE 12,6) 64.5% were men, 44,9% were single, 30% scored moderate or severe levels of depression. Having relationship acted as a protective factor of depression: for each patient relationship and moderate or severe levels of depression, there were 6 separated or widowed (P = 0,006; RP = 5,769; IC 95%: 1,349 – 24,674). High or moderate levels of anxiety were associated with depression (P = 0,004; RP = 2,750; IC 95% 1,391 – 5,436). Conclusions: Depression can affect often people living with HIV and high levels of anxiety associated with it. Having a relationship could favor the mood in these patients, probably because it is a source of social support. Keywords: Antiretroviral therapy, highly active; anxiety; depression; emotional adjustment; HIV; social support.</p

Minimal information for studies of extracellular vesicles (MISEV2023): From basic to advanced approaches

Extracellular vesicles (EVs), through their complex cargo, can reflect the state of their cell of origin and change the functions and phenotypes of other cells. These features indicate strong biomarker and therapeutic potential and have generated broad interest, as evidenced by the steady year-on-year increase in the numbers of scientific publications about EVs. Important advances have been made in EV metrology and in understanding and applying EV biology. However, hurdles remain to realising the potential of EVs in domains ranging from basic biology to clinical applications due to challenges in EV nomenclature, separation from non-vesicular extracellular particles, characterisation and functional studies. To address the challenges and opportunities in this rapidly evolving field, the International Society for Extracellular Vesicles (ISEV) updates its 'Minimal Information for Studies of Extracellular Vesicles', which was first published in 2014 and then in 2018 as MISEV2014 and MISEV2018, respectively. The goal of the current document, MISEV2023, is to provide researchers with an updated snapshot of available approaches and their advantages and limitations for production, separation and characterisation of EVs from multiple sources, including cell culture, body fluids and solid tissues. In addition to presenting the latest state of the art in basic principles of EV research, this document also covers advanced techniques and approaches that are currently expanding the boundaries of the field. MISEV2023 also includes new sections on EV release and uptake and a brief discussion of in vivo approaches to study EVs. Compiling feedback from ISEV expert task forces and more than 1000 researchers, this document conveys the current state of EV research to facilitate robust scientific discoveries and move the field forward even more rapidly

Reduction of power transmission losses in high-speed rail systems through efficient scheduling

The need to reduce overall energy consumption motivates the search for ways to improve energy use by transportation. Electrification has helped to significantly reduce the energy intensity of rail transportation. On today’s high-speed lines, power flows between trains and traction transformers are generally transmitted through the 2x25 electrification system. Although most of the energy provided to the railway system is consumed by the moving trains, a part of the energy is lost in the electrification system itself. In this study, dynamic computer simulations of realistic high-speed rail operating scenarios are developed and the energy losses in the electrification system are evaluated. The results show that power transmission losses are significant, and their value depends on the operation scenario. Finally, a method for selecting the minimum transmission loss operating scenarios is proposed, without modifying the transportation capacity offered or altering the resources required for the operation of a high-speed rail

Detection and quantification of bar breakage harmonics evolutions in inverter-fed motors through the dragon transform

[EN] The problem of detecting and quantifying bar breakage harmonics in inverter-fed induction motors has not been solved by the time-frequency transforms present in the technical literature. The paper proposes a new transform, called dragon transform, to solve this problem. The dragon atoms are defined with shapes perfectly adapted to the harmonic trajectories in the time-frequency plane, no matter how complex they are, enabling the precise tracing of the harmonics to be detected. A quantification method is also proposed, which obtains for the first time in the technical literature, the time evolutions of the harmonic amplitudes during a complex transient such as the start-up and the steady state of an inverter-fed motor. The transform performance is validated testing the induction motor under different load levels.Fernández-Cavero, V.; Pons Llinares, J.; Duque-Perez, O.; Morinigo-Sotelo, D. (2021). Detection and quantification of bar breakage harmonics evolutions in inverter-fed motors through the dragon transform. ISA Transactions. 109:352-367. https://doi.org/10.1016/j.isatra.2020.10.02035236710

State of the Art and Trends in the Monitoring, Detection and Diagnosis of Failures in Electric Induction Motors

Despite the complex mathematical models and physical phenomena on which it is based, the simplicity of its construction, its affordability, the versatility of its applications and the relative ease of its control have made the electric induction motor an essential element in a considerable number of processes at the industrial and domestic levels, in which it converts electrical energy into mechanical energy. The importance of this type of machine for the continuity of operation, mainly in industry, is such that, in addition to being an important part of the study programs of careers related to this branch of electrical engineering, a large number of investigations into monitoring, detecting and quickly diagnosing its incipient faults due to a variety of factors have been conducted. This bibliographic research aims to analyze the conceptual aspects of the first discoveries that served as the basis for the invention of the induction motor, ranging from the development of the Fourier series, the Fourier transform mathematical formula in its different forms and the measurement, treatment and analysis of signals to techniques based on artificial intelligence and soft computing. This research also includes topics of interest such as fault types and their classification according to the engine, software and hardware parts used and modern approaches or maintenance strategies

Maintenance Models Applied to Wind Turbines. A Comprehensive Overview

Wind power generation has been the fastest-growing energy alternative in recent years, however, it still has to compete with cheaper fossil energy sources. This is one of the motivations to constantly improve the efficiency of wind turbines and develop new Operation and Maintenance (O&amp;M) methodologies. The decisions regarding O&amp;M are based on different types of models, which cover a wide range of scenarios and variables and share the same goal, which is to minimize the Cost of Energy (COE) and maximize the profitability of a wind farm (WF). In this context, this review aims to identify and classify, from a comprehensive perspective, the different types of models used at the strategic, tactical, and operational decision levels of wind turbine maintenance, emphasizing mathematical models (MatMs). The investigation allows the conclusion that even though the evolution of the models and methodologies is ongoing, decision making in all the areas of the wind industry is currently based on artificial intelligence and machine learning models