A method for wide frequency range modeling of power transformers and rotating machines

Soysal, A.O.

doi:10.1109/61.248288

Cited by 41 publications

(26 citation statements)

References 24 publications

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“…The main insulation of the transformer is represented as interwinding capacitance (C w ) connecting primary and secondary windings. The influence of magnetic core is not included in this ladder network since the leakage flux is predominant during impulse phenomena . A suitable terminal connection and system function pair (transfer function, ie, TF oc , TF sc , TF pr ) is selected from the numerous possibilities of 14 x 6 x 2 = 168, listed in Figure 1 and Table 1 in the work of Satish and Saravanakumar .…”

Section: Methodsmentioning

confidence: 99%

“…Suppose, if the influence of the winding‐core assembly is minimized, then there exists an opportunity to widen the high‐frequency cutoff limit. A possible way to minimize the influence of winding core assembly is via careful selection of terminal connection and system function pair . This is verified through the simulation of a circuit model representation of an insulation and ladder network model and later, experimentally verified on model coils and in‐service transformers.…”

Section: Introductionmentioning

confidence: 94%

“…The natural frequencies of a transformer are clearly defined based on the number of windings, type of windings, their spatial position, arrangement and clearances, insulation arrangements/geometry, etc . Therefore, the existence of a correlation between natural frequencies and mechanical integrity of winding‐core assembly is understood .…”

Section: Model Selection and Assumptionmentioning

confidence: 99%

“…The same must be found among the vast possibilities at least via employing the brute‐force search method. It is reported that the short‐circuited secondary winding will not influence the fundamental oscillations in the primary winding; hence, rendering itself in‐effective . Additionally, a system function pair must be identified, without which certain natural frequencies might render nonexcitable …”

Section: Introductionmentioning

confidence: 99%

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Theoretical considerations while applying sweep frequency response analysis method in determining the interwinding capacitance of power transformers at higher frequencies

Arumugam

2019

Engineering Reports

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This paper systematically investigates on theoretical and practical aspects of frequency response analysis method in evaluating the dielectric integrity of transformers. Current practices focus on interwinding capacitances as they contain sensitive diagnostic information of transformer windings, magnetic core, and insulation. However, these procedures are inadequate as they are experience based, frequency limited, and overlook the electromagnetic influence of winding core during interwinding capacitance measurements. Corresponding interpretations are subjective and require an expert's decision. Clearly, a method based on trials and involving subjective analysis procedures may render inaccurate and unreliable results. On contrary, if the influence of winding core is minimized, then the high‐frequency cutoff limit can be widened, and the interwinding capacitances can be accurately determined. Presumably, the influence of winding core can be minimized via careful selection of terminal connection, system function pair. For this purpose, resistance‐capacitance and ladder network models describing the impulse behavior of winding‐insulation‐core of transformers are simulated. A suitable terminal connection, system function pair that minimizes the influence of winding‐core is identified. Subsequently, the sensitivity of the proposed method and the accuracy of interwinding capacitance measured are ascertained through comparative analysis and experimentally verified on model coils and transformers. Pertinent interpretations are objective and reveal the sensitive diagnostic information of transformers.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 94%

Section: Model Selection and Assumptionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Theoretical considerations while applying sweep frequency response analysis method in determining the interwinding capacitance of power transformers at higher frequencies

Arumugam

2019

Engineering Reports

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show abstract

“…Therefore, the main objective is to demonstrate localization of winding deformation based on frequency response measurements. A critical analysis of research performed so far, pertaining to this topic, reveals that all earlier efforts can essentially be grouped into the following categories, viz., detecting deformation in transformer windings (Lech & Tyminski, 1966;Dick & Erven, 1978;Rahimpour et al, 2003), assessing sensitivity and correlation between type of fault and measured quantity (Ryder, 2003;Florkowski & Furgal, 2003;Islam, 2000), and, developing circuit models and rational function approximations (Morched et al, 1993;Oguz Soysal, 1993;Gustavsen & Semlyen, 1999). As a matter of fact, there has been no previous attempt to localize deformation along a transformer winding using frequency response data, and hence it is worthy of consideration.…”

Section: Objective and Backgroundmentioning

confidence: 99%