Sweep frequency response analysis (SFRA) for the assessment of winding displacements and deformation in power transformers

Secue, J.; Mombello, Enrique E.

doi:10.1016/j.epsr.2007.08.005

Cited by 129 publications

(65 citation statements)

References 12 publications

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“…For inexperienced personnel, numbers come in handy to detect the problem based on some criterion given to them. Recent literature survey [9][10][11][12][13][14][15][16][17] indicates various important numerical techniques for the detection of a defect. Definitions of some of these numerical parameters [20][21] Viz., Correlation Co-efficient (CC), Mean square error (MSE), Absolute Sum of Logarithmic Error (ASLE) , Maximum absolute difference(MABS), Min-Max ratio(MM) and Standard Deviation(SD) and they are computed.…”

Section: Application Of Numerical Parametersmentioning

confidence: 99%

“…Many attempts have been made and are being continued to develop an evaluation method that can be applied by inexperienced personnel using numerical methods [9][10][11][12][13][14][15][16][17]. This paper presents the results of SFRA measurement work and investigations carried out on a transformer for inter turn and radial displacement simulated faults to study the applicability of various numerical tools for diagnosing the integrity of transformer windings.…”

Section: Introductionmentioning

confidence: 99%

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Application of numerical techniques to FRA data for diagnosing integrity of transformer windings

Prameela¹,

Nirgude

2015

2015 International Conference on Condition Assessment Techniques in Electrical Systems (CATCON)

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The paper presents the investigations carried out on a transformer for various simulated faults to obtain FRA data and study the applicability of various numerical techniques. The numerical parameters Viz., Min-Max ratio (MM), Mean Square Error (MSE), Maximum Absolute Difference (MABS), Absolute Sum of Logarithmic Error (ASLE), Standard Deviation (SD) and Correlation Coefficient (CC) computed in three different frequency bands are presented to aid the interpretation of SFRA data. Frequency responses among identical phases of the sister units and different phases of a healthy three phase transformer were used to obtain the proposed representative numerical parameters for comparison. Deviation of the numerical parameters from the proposed representative parameters for different types of simulated faults is analyzed to diagnose the condition of the transformer. The analysis of the deviations in the parameters suggests the possibility of using the numerical approach to diagnose the transformer winding displacements and deformations. Interpretations of the results presented also indicate the possibility of discriminating the faulty winding using numerical parameter, computed from reference base data, symmetry of the windings, sister units and type of winding approach, and comparing them with the proposed representative numerical parameters presented in the paper.

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Section: Application Of Numerical Parametersmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Application of numerical techniques to FRA data for diagnosing integrity of transformer windings

Prameela¹,

Nirgude

2015

2015 International Conference on Condition Assessment Techniques in Electrical Systems (CATCON)

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“…La RF puede ser utilizada para realizar diagnóstico en transformadores, técnica FRA o SFRA (Secue, 2008), o para obtener modelos matemáticos bien sean circuitos eléctricos o funciones de transferencia (Velilla, 2008). En este trabajo se optó por ajustar las RF mostradas en la Fig.…”

Section: Ajuste De La Ganancia De Tensión a Funciones De Transferenciaunclassified

“…Por otra parte, la técnica del análisis de respuesta en frecuencia se ha utilizado en el diagnóstico de fallas en transformadores a partir de la comparación de varios registros de respuestas en frecuencia (Secue, 2008). Este trabajo, abordó el tema de la transferencia de tensión, evaluando el comportamiento de transformadores monofásicos de baja potencia utilizados en aplicaciones electrónicas ante excitaciones tipo impulsos de tensión, considerando tanto el vacío como carga resistiva en el lado de baja.…”

Section: Introductionunclassified

Transferencia de Impulsos y Ganancia de Tensión en Transformadores Monofásicos de Baja Potencia

et al. 2012

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ResumenSe evaluó la transferencia de impulsos de tensión 1.2/50µs y 3/23µs del primario al secundario, en tres transformadores monofásicos utilizados en aplicaciones electrónicas, uno de 18W, otro de 85W y un autotransformador de 50W, considerándolos en vacío y con carga resistiva en el secundario. El autotransformador fue el que presentó mayor amortiguamiento y menor valor máximo en el impulso transferido. La máxima transferencia de tensión ocurrió en vacío y se analizaron las respuestas en frecuencia de la ganancia de tensión de los transformadores en vacío entre 10Hz y 1MHz, ajustándolas a funciones de transferencia para modelar la transferencia de impulsos de tensión. La confrontación de los resultados experimentales y teóricos tanto en el dominio del tiempo como en el dominio de la frecuencia, mostraron información valiosa sobre la transferencia de los impulsos de tensión en los transformadores monofásicos. Palabras clave: transformador monofásico, impulsos de tensión, ganancia de tensión, respuesta en frecuencia, función de transferencia. Impulse Transfer and Voltage Gain in Single Phase Low Power Transformers AbstractThe voltage impulse transferences of 1.2/50µs and 3/23µs from the primary to the secondary winding was tested in three single phase transformers used in electronic applications; two transformers of 85W and 18W, and one autotransformer of 50W were used under no load and under resistive load conditions. The autotransformer showed higher damping and lower peak value in the transferred voltage impulse than the other transformers. The maximum voltage value in the secondary winding was obtained at no load condition and the frequency response of the voltage gain of the transformers between 10Hz and 1MHz were analyzed and fitted to transfer functions to model the voltage impulse transferences. The comparison of experimental results with those obtained from transfer functions in the frequency and time domain provides valuable information about the transferred voltage impulses in single phase transformers.

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“…After the introduction of ASLE in 2005, various literatures have implemented the indicator such as [37][38][39]. A newer indicator was proposed in [40] which is known as comparative standard deviation (CSD).…”

Section: Statistical Analysis For Comparing Responsesmentioning

confidence: 99%

Frequency response analysis for transformer winding condition monitoring

Yousof¹,

Fairouz²

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The large power transformer is one of the most expensive assets in a power system network.Special attention needs to be taken to monitor this expensive asset. Among the most critical aspect of a transformer that needs to be monitored is the mechanical condition of the windings and core.One of the best approaches to achieve this is by performing the Frequency Response Analysis (FRA) test on the transformer. The test measures the transfer function response of the transformer winding. If any physical changes occur, it will affect the original response, which can be used to detect any abnormality. However, the critical challenge in this technique is to correctly interpret the measured response in determining the transformer status. Although various investigations have focussed on this issue, the interpretation aspect of FRA is still not fully established.In order to contribute to the improvement of a FRA interpretation scheme, this thesis investigates the sensitivity of FRA measurement on several common winding deformations and explores a new potential diagnostic scheme of FRA. A wide range of power transformers have been used throughout this study ranging from a small sized prototype laboratory transformer to a 30 MVA power transformer installed at a substation.Initially, a mathematical model is established to simulate the frequency response of a power transformer. This is achieved by comparing three models, which are available in the literature.These models are compared in terms of their accuracies to simulate the response and their applicability to studying winding deformation. The comparison shows that the multi-conductor transmission line model is the best approach due to its ability to model each turn of a winding.With the developed model, the sensitivity of the winding response is investigated. This study shows that a minor change to the winding geometrical parameters could cause a considerable change on the response. On a different issue, it is found that a similar winding failure mode may cause a different response variation depending on the winding type. A study based on measurement is also conducted to investigate the influence of windings from other phases to the tested winding. It reveals that the end to end open circuit response is susceptible to the condition of an adjacent winding. Additionally, investigation on the winding response sensitivity due to the tap changer setting is also carried out.This thesis studies several winding deformations, which includes tilting and bending of conductors and inter-disc fault. These three faults are examined in terms of their severity of damage and location of the fault. Statistical analysis is applied to determine the overall condition of the winding. On the other hand, transfer function based analysis is proposed to extract further iii information if the winding is found to be faulty. This includes using the pole plot and Nyquist plot, in which the latter proved to be useful for all winding failure modes. The transfer function is achieved by applying vec...

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Sweep frequency response analysis (SFRA) for the assessment of winding displacements and deformation in power transformers

Cited by 129 publications

References 12 publications

Application of numerical techniques to FRA data for diagnosing integrity of transformer windings

Application of numerical techniques to FRA data for diagnosing integrity of transformer windings

Transferencia de Impulsos y Ganancia de Tensión en Transformadores Monofásicos de Baja Potencia

Frequency response analysis for transformer winding condition monitoring

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