The Experts below are selected from a list of 270 Experts worldwide ranked by ideXlab platform
Ernst Gockenbach - One of the best experts on this subject based on the ideXlab platform.
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Sweep Frequency response analysis for diagnosis of low level short circuit faults on the windings of power transformers an experimental study
International Journal of Electrical Power & Energy Systems, 2012Co-Authors: Vahid Behjat, Alireza Setayeshmehr, Ali Vahedi, Hossein Borsi, Ernst GockenbachAbstract:Abstract This contribution is aimed at obtaining diagnosis criteria for detection of low-level short circuit faults throughout Sweep Frequency response analysis (SFRA) measurements on the transformer windings. Significant advantages would accrue by early detection of low level short circuit faults within the transformer, since if not quickly detected, they usually develop into more serious faults which result in irreversible damage to the transformer and the electrical network, unexpected outages and the consequential costs. A Finite Element Model (FEM) of the tested transformer has been developed to assist in justifying the modifications of the winding Frequency response as a result of fault occurrence. Successful operation of the SFRA method in precisely detecting interturn faults along the transformer windings, even down to a few shorted turns on the winding, is proved through a large number of experiments and measurements. Improving the interpretation of the SFRA measurements needs complementary statistical indicators. The usage of correlation coefficient and spectrum deviation for comparison of the Frequency responses obtained through SFRA measurements provides quantitative indicators of the fault presence on the transformer windings and also the fault severity level in the shorted turns.
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Sweep Frequency response analysis for diagnosis of low level short circuit faults on the windings of power transformers: An experimental study
International Journal of Electrical Power and Energy Systems, 2012Co-Authors: Vahid Behjat, Alireza Setayeshmehr, Ali Vahedi, Hossein Borsi, Ernst GockenbachAbstract:This contribution is aimed at obtaining diagnosis criteria for detection of low-level short circuit faults throughout Sweep Frequency response analysis (SFRA) measurements on the transformer windings. Significant advantages would accrue by early detection of low level short circuit faults within the transformer, since if not quickly detected, they usually develop into more serious faults which result in irreversible damage to the transformer and the electrical network, unexpected outages and the consequential costs. A Finite Element Model (FEM) of the tested transformer has been developed to assist in justifying the modifications of the winding Frequency response as a result of fault occurrence. Successful operation of the SFRA method in precisely detecting interturn faults along the transformer windings, even down to a few shorted turns on the winding, is proved through a large number of experiments and measurements. Improving the interpretation of the SFRA measurements needs complementary statistical indicators. The usage of correlation coefficient and spectrum deviation for comparison of the Frequency responses obtained through SFRA measurements provides quantitative indicators of the fault presence on the transformer windings and also the fault severity level in the shorted turns. © 2012 Elsevier Ltd. All rights reserved.
Akshay A. Pandya - One of the best experts on this subject based on the ideXlab platform.
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Sweep Frequency RESPONSE ANALYSIS (SFRA)AN APPROACH TO DETECT HIDDENTRANSFORMER FAULTS
International Journal of Advanced Research in Electrical Electronics and Instrumentation Energy, 2020Co-Authors: Akshay A. Pandya, B. R. ParekhAbstract:Sweep Frequency response analysis is a major advance in transformer condition analysis. Frequency response is performed by applying a low voltage signal of varying frequencies to the transformer windings and measuring both the input and output signals. The ratio of these two signals gives the required response. This ratio is called the transfer function of the transformer from which both the magnitude and phase can be obtained. Changes in Frequency response as measured by SFRA techniques may indicate a physical change inside the transformer, the cause of which then needs to be identified and investigated.
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Power Transformer Core Behavior Diagnosis Using Sweep Frequency Response Analysis
2020Co-Authors: Vipul N. Rajput, Akshay A. Pandya, Gaurang K. SharmaAbstract:Abstract- Transformers, one of the most important components of the power systems, play a significant role in facilitating transfer of power to end users. Power transformer is essential equipment of electrical network. Therefore, there is a great interest is taken and researches are held in its physical state. Frequency Response Analysis (FRA) is nowadays an appreciated preventive technique used for transformer core fault diagnosis and maintenance in order to detect winding deformation and core fault. But, in spite of the advantages of FRA, a systematic diagnosis procedure has not been still developed due to the physical meaning of the Frequency Response is not really obtained. We have developed a three phase magnetic core model that provides the relations among the Frequency Response and the different parts inside the three phase transformer. The different case study and experiment results are discussed which are obtained by Sweep Frequency response analysis (SFRA).
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Conditioning Monitoring of Transformer Using Sweep Frequency Response for Winding Deformation
2020Co-Authors: Ronak H. Vaishnav, Akshay A. PandyaAbstract:Monitoring the health of power transformer is important for the reliability of electrical power supply. Sweep Frequency Response Analysis is a powerful tool for analysing transformer health and mechanical integrity is used to check the eventual change in the internal geometry of the active parts of the transformer, displacements or deformations. The main causes of such as the presence of external short-circuit. These faults may result in complete rupture of insulation which will result in complete damage of the winding. A benchmark winding is considered which has already been validated for experimental studies. The winding is modelled using finite element method (FEM) based software and parameters such as capacitance and inductance are calculated for 10 section healthy helical coil, by these parameter values, SFRA plots are obtained which are a set of reference for deformation analysis. The winding is modelled as radially and axially deformed coils using FEM software. The deformation is carried at five consecutive sections; purpose of doing so to find the location of deformation corresponding to a similar deformation in an actual transformer. The advantage of the FEM modelling is, we can deform the sections as desired unlike in an actual case and obtain the fingerprint graphs from the modified parameter values. The SFRA plots are obtained for the deformations at five sections for axial and radial deformations. A comparison is carried between the SFRA plots for deformed cases with reference set & deviations observed are in resonant frequencies & peak current magnitude. So the type and location of deformation can be found corresponding to a similar deformation in an actual power transformer.
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interpretation of Sweep Frequency response analysis sfra traces for the open circuit and short circuit winding fault damages of the power transformer
International Journal of Electrical Power & Energy Systems, 2014Co-Authors: Akshay A. Pandya, B. R. ParekhAbstract:Abstract This paper presents how interpretation of Sweep Frequency Response Analysis (SFRA) traces can be done for the open circuit and short circuit winding faults on the 10 kV A power transformer. The power transformer of rating 10 kV A, 11,000 V/440 V, 3-phase, 50 Hz, Dyn11 has been specially developed in-house for carrying out SFRA testing by practically simulated various transformer damages on it. Authors have discussed here open circuit and short circuit winding faults damages. The HV “W” phase open fault and HV “U” and “V” short fault has been practically simulated on the transformer separately. The result of these simulated faults are presented and discussed. The motivation of this presented work is to extend the guide line approach. Since the SFRA interpretation is based on experience, such databases are thought to be of great importance when interpreting SFRA response. The evaluation of the SFRA responses against guide lines and experience have to be performed and conclusions regarding usefulness of each simulation has been drawn and at last overall conclusion has also been drawn.
Vahid Behjat - One of the best experts on this subject based on the ideXlab platform.
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Sweep Frequency response analysis for diagnosis of low level short circuit faults on the windings of power transformers an experimental study
International Journal of Electrical Power & Energy Systems, 2012Co-Authors: Vahid Behjat, Alireza Setayeshmehr, Ali Vahedi, Hossein Borsi, Ernst GockenbachAbstract:Abstract This contribution is aimed at obtaining diagnosis criteria for detection of low-level short circuit faults throughout Sweep Frequency response analysis (SFRA) measurements on the transformer windings. Significant advantages would accrue by early detection of low level short circuit faults within the transformer, since if not quickly detected, they usually develop into more serious faults which result in irreversible damage to the transformer and the electrical network, unexpected outages and the consequential costs. A Finite Element Model (FEM) of the tested transformer has been developed to assist in justifying the modifications of the winding Frequency response as a result of fault occurrence. Successful operation of the SFRA method in precisely detecting interturn faults along the transformer windings, even down to a few shorted turns on the winding, is proved through a large number of experiments and measurements. Improving the interpretation of the SFRA measurements needs complementary statistical indicators. The usage of correlation coefficient and spectrum deviation for comparison of the Frequency responses obtained through SFRA measurements provides quantitative indicators of the fault presence on the transformer windings and also the fault severity level in the shorted turns.
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Sweep Frequency response analysis for diagnosis of low level short circuit faults on the windings of power transformers: An experimental study
International Journal of Electrical Power and Energy Systems, 2012Co-Authors: Vahid Behjat, Alireza Setayeshmehr, Ali Vahedi, Hossein Borsi, Ernst GockenbachAbstract:This contribution is aimed at obtaining diagnosis criteria for detection of low-level short circuit faults throughout Sweep Frequency response analysis (SFRA) measurements on the transformer windings. Significant advantages would accrue by early detection of low level short circuit faults within the transformer, since if not quickly detected, they usually develop into more serious faults which result in irreversible damage to the transformer and the electrical network, unexpected outages and the consequential costs. A Finite Element Model (FEM) of the tested transformer has been developed to assist in justifying the modifications of the winding Frequency response as a result of fault occurrence. Successful operation of the SFRA method in precisely detecting interturn faults along the transformer windings, even down to a few shorted turns on the winding, is proved through a large number of experiments and measurements. Improving the interpretation of the SFRA measurements needs complementary statistical indicators. The usage of correlation coefficient and spectrum deviation for comparison of the Frequency responses obtained through SFRA measurements provides quantitative indicators of the fault presence on the transformer windings and also the fault severity level in the shorted turns. © 2012 Elsevier Ltd. All rights reserved.
Ting Li - One of the best experts on this subject based on the ideXlab platform.
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inversion of Sweep Frequency backscatter ionogram from monostatic hf sky wave radar
IEEE Geoscience and Remote Sensing Letters, 2013Co-Authors: Ning Li, Zhengyu Zhao, Chen Zhou, Gang Chen, Guobin Yang, Shuo Huang, Ting LiAbstract:The Wuhan Ionospheric Oblique Backscattering Sounding System (WIOBSS) is a monostatic high-Frequency sky-wave radar used for ionospheric remote sensing. The Sweep Frequency backscatter ionogram (SFBI) recorded by the WIOBSS contains both backscatter echo scattered by distant terrestrial surface and vertical incidence (VI) echo reflected by local ionosphere over the sounding station. The approach for SFBI inversion introduced in this letter requires input of leading edge and peak height derived from local VI echo. The final output of this SFBI inversion approach is the 2-D electron density distribution in a vertical plane aligned in the direction of sounding. In addition, the time and geographic variation of foF2 can be obtained from a series of SFBI inversion results. Two experiments have been utilized to validate the SFBI inversion approach, and the SFBI inversion results are found to be very close to the ionosonde data. The fast-converged feature of the approach makes it possible for applications in real time. The success of the SFBI inversion approach enables us to use the WIOBSS as a vehicle-mounted system to obtain ionosphere electron density profile over a large geographic area.
B. R. Parekh - One of the best experts on this subject based on the ideXlab platform.
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Sweep Frequency RESPONSE ANALYSIS (SFRA)AN APPROACH TO DETECT HIDDENTRANSFORMER FAULTS
International Journal of Advanced Research in Electrical Electronics and Instrumentation Energy, 2020Co-Authors: Akshay A. Pandya, B. R. ParekhAbstract:Sweep Frequency response analysis is a major advance in transformer condition analysis. Frequency response is performed by applying a low voltage signal of varying frequencies to the transformer windings and measuring both the input and output signals. The ratio of these two signals gives the required response. This ratio is called the transfer function of the transformer from which both the magnitude and phase can be obtained. Changes in Frequency response as measured by SFRA techniques may indicate a physical change inside the transformer, the cause of which then needs to be identified and investigated.
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interpretation of Sweep Frequency response analysis sfra traces for the open circuit and short circuit winding fault damages of the power transformer
International Journal of Electrical Power & Energy Systems, 2014Co-Authors: Akshay A. Pandya, B. R. ParekhAbstract:Abstract This paper presents how interpretation of Sweep Frequency Response Analysis (SFRA) traces can be done for the open circuit and short circuit winding faults on the 10 kV A power transformer. The power transformer of rating 10 kV A, 11,000 V/440 V, 3-phase, 50 Hz, Dyn11 has been specially developed in-house for carrying out SFRA testing by practically simulated various transformer damages on it. Authors have discussed here open circuit and short circuit winding faults damages. The HV “W” phase open fault and HV “U” and “V” short fault has been practically simulated on the transformer separately. The result of these simulated faults are presented and discussed. The motivation of this presented work is to extend the guide line approach. Since the SFRA interpretation is based on experience, such databases are thought to be of great importance when interpreting SFRA response. The evaluation of the SFRA responses against guide lines and experience have to be performed and conclusions regarding usefulness of each simulation has been drawn and at last overall conclusion has also been drawn.
