A Transformer Differential Relay with Second-Harmonic Restraint

Sharp, R. L.; Glassburn, W. E.

doi:10.1109/aieepas.1958.4500059

Cited by 81 publications

(40 citation statements)

References 5 publications

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“…However, the resulted inrush current has very high amplitude and it is in short-circuit current range, and it may create some dynamic stress in transformer winding [5]. The amplitude of these currents usually dose not exceed the one resulted in transformers, but the continuation of these stresses and their occurrence number usually exceeds the short circuit current that the protective relays interrupt it in few msec.…”

Section: Inrush Current Phenomenonmentioning

confidence: 99%

Synchronous Study of Ferroresonance and Inrush Current Phenomena and their Related Reasons in Ground Power Networks

Akrami¹,

Ghaderi²,

Ghadi³

2010

Scientific Journal of Riga Technical University. Power and Electrical Engineering

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Abstract. Energizing the power transformers usually results in flowing very high inrush currents. This harmful current can be minimized using controlled switching and considering the value of residual flux. But nowadays, developing the ground power networks results in high increment of ferroresonance phenomenon occurrence due to the line' capacitance reactance and nonlinear inductive reactance of power transformer's core. In this study, these transient phenomena and their cause have studied synchronously.

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Section: Inrush Current Phenomenonmentioning

confidence: 99%

Synchronous Study of Ferroresonance and Inrush Current Phenomena and their Related Reasons in Ground Power Networks

Akrami¹,

Ghaderi²,

Ghadi³

2010

Scientific Journal of Riga Technical University. Power and Electrical Engineering

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“…Also, various methods such as the restraint of dead angle [24], the inverse inductance scheme of transformer equivalent circuit [25], the restraint of voltage [26], the restraint of second harmonic [27], have been done to distinguish internal faults from inrush current. The second harmonic restraint is widely used in a standard differential protection.…”

mentioning

confidence: 99%

Control of unusual mal-operation of three-phase power transformer differential protection due to ultra saturation phenomenon based on Clarke׳s Transform and Discrete Wavelet Transform

Noshad

Ghanavati

Ahmadzadeh

et al. 2015

Renewable and Sustainable Energy Reviews

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“…Hayward [2] and Mathews [3] used all of the harmonics to restrain the differential relay for a transformer. Sharp and Glassburn [4] introduced the idea of harmonic blocking using the second harmonic. Einvall and Linders [5] introduced a composite restraint function with the second and fifth harmonics.…”

Section: Introductionmentioning

confidence: 99%

Saturation Detection-Based Blocking Scheme for Transformer Differential Protection

Lee

Won

et al. 2014

Energies

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This paper describes a current differential relay for transformer protection that operates in conjunction with a core saturation detection-based blocking algorithm. The differential current for the magnetic inrush or over-excitation has a point of inflection at the start and end of each saturation period of the transformer core. At these instants, discontinuities arise in the first-difference function of the differential current. The second-and third-difference functions convert the points of inflection into pulses, the magnitudes of which are large enough to detect core saturation. The blocking signal is activated if the third-difference of the differential current is larger than the threshold and is maintained for one cycle. In addition, a method to discriminate between transformer saturation and current transformer (CT) saturation is included. The performance of the proposed blocking scheme was compared with that of a conventional harmonic blocking method. The test results OPEN ACCESSEnergies 2014, 7 4572 indicate that the proposed scheme successfully discriminates internal faults even with CT saturation from the magnetic inrush, over-excitation, and external faults with CT saturation, and can significantly reduce the operating time delay of the relay.

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A Transformer Differential Relay with Second-Harmonic Restraint

Cited by 81 publications

References 5 publications

Synchronous Study of Ferroresonance and Inrush Current Phenomena and their Related Reasons in Ground Power Networks

Synchronous Study of Ferroresonance and Inrush Current Phenomena and their Related Reasons in Ground Power Networks

Control of unusual mal-operation of three-phase power transformer differential protection due to ultra saturation phenomenon based on Clarke׳s Transform and Discrete Wavelet Transform

Saturation Detection-Based Blocking Scheme for Transformer Differential Protection

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