Partial discharge localization in transformer windings using multi-conductor transmission line model

Jafari, Ali; Akbari, Asghar

doi:10.1016/j.epsr.2007.08.004

Cited by 40 publications

(20 citation statements)

References 9 publications

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“…The second feature of the vector's similarity with the first one will base its assignment to the first cluster or a new cluster. The system parameters determined by the user are the amount of dissimilarity between the clusters and the maximum number of clusters M. is calculated using (10) where and are extracted features from the recorded signals at 0 and 1.…”

Section: Hadamard and Haar Transformsmentioning

confidence: 99%

“…On the other hand, the location of PD in the transformer winding can also be established using the multiconductor transmission-line model (MTLM). Through this model, a comparison between the measured and calculated transfer function allows the best model parameters to be obtained, which are then used for PD localization [10]. The capability of optical sensors for PD detection has already been proven [11]- [13]; however, the methodology for identification and localization of PD sources using optical sensors is still under investigation [14].…”

Section: Introductionmentioning

confidence: 99%

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Partial Discharge Localization in Power Transformers Using Neuro-Fuzzy Technique

Homaei

Moosavian

Illias

2014

IEEE Trans. Power Delivery

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Partial discharge (PD) is the most common sources of insulation failure in power transformers. The most important tools for quality assessment of power transformers are PD detection, measurement, and classification. As for the maintenance and repair of transformers, the major importance is the techniques for locating a PD source. The transfer function-based (TF) method for power transformers' winding in the high-frequency range is commonly used in power engineering applications, such as transient analysis, insulation coordination, and in transformer design. Although it is possible to localize PD in transformer winding using the transfer function (TF) method, this method cannot be used for transformers with no design data. Previous attempts toward finding a feature that localizes PD in transformers in general that lineate with PD location were found to be less successful. Therefore, in this paper, a neuro-fuzzy technique that uses unsupervised pattern recognition was proposed to localize PD source in power transformers. The proposed method was tested on a medium-voltage transformer winding in the laboratory. The results showed a significant improvement in localizing PD for major types of PD compared to currently available techniques, such as orthogonal transforms and the calibration line method.

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Section: Hadamard and Haar Transformsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Partial Discharge Localization in Power Transformers Using Neuro-Fuzzy Technique

Homaei

Moosavian

Illias

2014

IEEE Trans. Power Delivery

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“…In this equation, D m is the winding diameter, w is the width of the conductor axis, t p is the paper thickness in both sides of the conductor, ε 0 is the dielectric coefficient of air, and ε p is the relative dielectric coefficient of the paper [8,9].…”

Section: Calculation Of Capacitancementioning

confidence: 99%

Using the finite element method to calculate parameters for a detailed model of transformer winding for partial discharge research

Hosseini¹,

Madar²,

Vakilian³

2015

Turk J Elec Eng & Comp Sci

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Abstract:Power transformers are considered to be one of the most essential and costly pieces of equipment in a power system. Identifying insulation faults in the shortest possible time prevents the occurrence of irreparable damage. Partial discharge (PD) is one of the most significant insulation faults. The first step in the study of PD is the precise modeling of transformer winding at high frequencies. In this paper, the finite element method is used to calculate the parameters for a detailed model of transformer winding. For this reason, a detailed model of transformer winding and the analytic formulations are first presented for the calculation of the parameters of the model. Using two-dimensional finite element methods, the 20-kV transformer winding is then simulated according to exact technical specifications and designed using Maxwell software. After that, the parameters for the detailed model presented in this paper are derived and calculated.Finally, the validity of the model in the frequency range is determined by applying a similar PD pulse on the real and simulated models.

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“…It is also employed to study the behaviour of transformer windings under very fast transient overvoltage such as in [61,62] and for studying the propagation of partial discharge pulses as in [63,64]. As mentioned in [65], the concept of MTL refers to a certain number of parallel conductors which transmit electrical signals.…”

Section: Multi-conductor Transmission Line (Mtl)mentioning

confidence: 99%

“…For the ground capacitance, it is considered as the capacitance between HV and LV windings since the LV winding is connected to ground as shown in Figure 3.4. Therefore, the ground capacitance of a disc can be computed using (3.37) which is based on cylindrical or coaxial capacitor formula [59,64,71]. …”

Section:  mentioning

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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Partial discharge localization in transformer windings using multi-conductor transmission line model

Cited by 40 publications

References 9 publications

Partial Discharge Localization in Power Transformers Using Neuro-Fuzzy Technique

Partial Discharge Localization in Power Transformers Using Neuro-Fuzzy Technique

Using the finite element method to calculate parameters for a detailed model of transformer winding for partial discharge research

Frequency response analysis for transformer winding condition monitoring

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