Influence of Phase Connection and Terminal Conditions on Natural Frequencies of Three-Phase Transformer Windings

Gururaj, Bharathi

doi:10.1109/tpas.1968.292229

Cited by 10 publications

(7 citation statements)

References 2 publications

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“…In view of this, a careful selection of terminal configuration (terminal connection, system function) may be exercised to minimize the influence of winding-core assembly. [30][31][32][33][34][35][36]…”

Section: • Considerations While Applying Sfra Methods In Measuring In...mentioning

confidence: 99%

“…Transformer winding-core arrangement could be perceived as a resistance, inductance, and capacitance in series/parallel combination. [30][31][32][33][34][35][36] More precisely, the winding parameters are described using resistance, inductances while the insulation parameters are represented in terms of series/parallel combination of resistance, and capacitances. Figure 1 shows the high-frequency circuit model of a two-winding transformer.…”

Section: Transformer-winding Parameters and Deduced Mechanismsmentioning

confidence: 99%

“…3,7 This behavior can be adequately represented by the impulse circuit representation of transformer windings and the same is discussed well in several literatures. [1][2][3][30][31][32][33][34][35][36][37] F I G U R E 1 High-frequency circuit model of a two-winding transformer winding describing its impulse behavior…”

Section: Transformer-winding Parameters and Deduced Mechanismsmentioning

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. In view of this, a careful selection of terminal configuration (terminal connection, system function) may be exercised to minimize the influence of winding‐core assembly Current IEEE and IEC standards and literatures on measuring interwinding capacitance The current IEEE standard recommends a terminal configuration while measuring the interwinding capacitance of transformers .…”

Section: Literature Review and Motivationmentioning

confidence: 99%

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Experimental validation of using frequency response analysis method in measuring interwinding capacitance of power transformers

Arumugam

2019

Engineering Reports

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The interwinding capacitance of transformers describes the diagnostic status of winding‐insulation and its geometry. Naturally, there is a constant drive in improvising the existing methods and to attain accurate information while measuring interwinding capacitance of a transformer. In this regard, frequency response analysis method is increasingly used in measuring the interwinding capacitance of transformers. The primary reason for applying this method is to establish a faster evaluation method for diagnosing the status of the winding‐insulation through the interwinding capacitances. However, the pertinent measurement procedures are inadequate as they tend to resolve the interwinding capacitances along with the electromagnetic influence of winding‐core assembly, thus making it difficult to diagnose the status of the winding‐insulation. This intricacy could be overcome by making an optimal choice of terminal configuration, that is, a combination of terminal connection, system function, mode of excitation that would minimize the electromagnetic influence of winding‐core in their respective spectra. In this context, the theoretical aspects of making an optimal choice of terminal configuration have already been investigated, and the suitability of the same on actual in‐service power and distribution transformers needs to be validated. This forms the primary focus of this article. A rigorous and systematic experimental study is adapted to verify the existing findings and validate the same on larger power and distribution transformers. After verification, the proposed method may be identified as sensitive in determining the interwinding capacitance of transformers and further recommended during frequency response measurements.

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Section: • Considerations While Applying Sfra Methods In Measuring In...mentioning

confidence: 99%

Section: Transformer-winding Parameters and Deduced Mechanismsmentioning

confidence: 99%

Section: Transformer-winding Parameters and Deduced Mechanismsmentioning

confidence: 99%

Section: Literature Review and Motivationmentioning

confidence: 99%

See 2 more Smart Citations

Experimental validation of using frequency response analysis method in measuring interwinding capacitance of power transformers

Arumugam

2019

Engineering Reports

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“…Further, incorporating the influence of terminal conditions, point of excitation and phase connections of single and three phase transformer windings on resonant frequencies was also reported. In the present context, it is important to note the observation made in [13], that in some terminal connections, a few natural frequencies are rendered nonexcitable. Obviously, such connections are best avoided.…”

Section: Literature Review and Motivationmentioning

confidence: 84%

Identification of Terminal Connection and System Function for Sensitive Frequency Response Measurement on Transformers

Satish

Saravanakumar

2008

IEEE Trans. Power Delivery

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Frequency response measurement on a transformer is a low voltage, off-line exercise. So, it virtually permits determination of any network/system function, by imposing any desired terminal condition for the nontested windings. The terminal conditions employed have significant influence on the achievable fault detection ability, and maximizing this ability should obviously be one of the main aims of frequency response measurements. Simply stated, this requirement translates to the ability to identify/measure as many natural frequencies as possible. However, there is a practical limitation that not all network/system functions can exhibit all natural frequencies. Hence, it is necessary to determine the most appropriate combination of terminal connection and system function for achieving this objective. Considering a two-winding transformer representation, system functions for different terminal conditions were computed. Depending on number of natural frequencies distinguishable in the amplitude frequency response of a system function, each measuring condition was ranked. Thus, it led to identification of the best configuration. Later, these findings were verified on an actual transformer. Performance of best configuration was compared with currently employed low-voltage impulse (LVI) test (used during short-circuit testing of transformers) and sweep frequency response measurement test conditions, and found to be better. In conclusion, it is believed that after adequate field verifications, the identified configuration can be declared as the preferred way of making frequency response measurements on transformers.

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A method to estimate the lightning multiline flashover on transmission line towers

Anjo

Komoda

1977

Electrical Engineering Japan

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Influence of Phase Connection and Terminal Conditions on Natural Frequencies of Three-Phase Transformer Windings

Cited by 10 publications

References 2 publications

Experimental validation of using frequency response analysis method in measuring interwinding capacitance of power transformers

Experimental validation of using frequency response analysis method in measuring interwinding capacitance of power transformers

Identification of Terminal Connection and System Function for Sensitive Frequency Response Measurement on Transformers

A method to estimate the lightning multiline flashover on transmission line towers

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