A current-based solution for transformer differential protection. I. Problem statement

Guzmán, Armando; Zocholl, Z.; Benmouyal, G.; Altuve, H.J.

doi:10.1109/61.956726

Cited by 108 publications

(19 citation statements)

References 21 publications

(45 reference statements)

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“…In order to ensure the reliability of the method, the current transformer saturation was also concerned in all of investigated cases. It was found that through several cases examined, the time to CT saturation often took about one cycle or longer [21,22], the influences of CT saturation was thus rarely observed. From scenarios considered in this study, although the currents may not always be a well-defined profile, the proposed method was confirmed to serve as an auxiliary alternative for transformer overcurrent recognition in addition to existing approaches.…”

Section: Measured Fault Currentmentioning

confidence: 92%

Enhancement of auxiliary overcurrent protection in transformers using novel feature extraction algorithms

Huang

Wan

2010

Int Trans Elec Energy Syst

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SUMMARYIn this paper, a feature extraction approach embedded with wavelet computation is applied to enhance the auxiliary overcurrent protection, by which the transformer inrush current discriminating from internal fault can be achieved. This proposed method starts with a feature extraction of acquired differential current waveform following the execution of wavelet computation. Then, the extracted features are expressed as a group of quantitative turning points to serve as indicators for overcurrent recognition. It is found that by this way of design, the inrush current can be effectively discriminated from the fault current. To validate the effectiveness of the method, it was applied to various simulated scenarios as well as employed to inspect a 60 MVA, 161/23.9 kV transformer connected to a 161 kV power system in Taiwan. Test results help support the feasibility of the method for the application considered.

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Section: Measured Fault Currentmentioning

confidence: 92%

Enhancement of auxiliary overcurrent protection in transformers using novel feature extraction algorithms

Huang

Wan

2010

Int Trans Elec Energy Syst

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“…The fault current has a higher slope first and then its slope decreases so a fault current behaves as a flat-toped wave. These differences originate from the different cases and nature of fault and inrush currents and are consistent for different transformer and power system parameters [1].…”

Section: Different Behaviors Of Fault and Inrush Currentmentioning

confidence: 93%

“…These systems require small fault clearing time to protect the equipments and to guarantee the system stability when short circuit occurs. In some possible conditions, the conventional algorithms such as those based on the principle of the second harmonic, cannot respond in the due time or may incorrectly respond to the transformer inrush current [1]. Therefore, researchers have been motivated to develop more secure differential protection algorithms in order to improve the operation speed and also to improve the reliability by distinguishing the transformer internal faults from short circuit fault.…”

Section: Introductionmentioning

confidence: 99%

A runs test‐based method for discrimination between internal faults and inrush currents in power transformers

Fani

Golshan

Abyaneh

et al. 2010

Int Trans Elec Energy Syst

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SUMMARYA new method based on runs test is proposed to distinguish the inrush currents from the internal faults in power transformers, which is derived from the inherent differences between these waveforms. First, two statistical hypotheses that represent these differences are defined. Then by testing these hypotheses using runs test and by comparing the outputs of the hypotheses, a criterion to identify the internal fault is obtained. A total of 200 experimental cases are used to test the performance of the technique. In all of the tests, the proposed method accurately distinguished between fault and inrush currents without any errors. Also the suitable performance of the method is demonstrated by simulation of different faults and switching conditions on a power transformer. For this purpose, a small part of Iran power system involving a power transformer and the transmission lines on both sides of the transformer has been considered. To include effective factors on differential current components, the elements of this power system have been precisely modeled in PSCAD/EMTDC.

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“…The conventional approach uses the principle of the second harmonic restraint [5]. The main drawback of the method is that the possible harmonic in the internal fault current can cause differential relay either not to operate or to operate with a long delay.…”

Section: Introductionmentioning

confidence: 99%

A frequency curves analysis-based method for transformers differential protection

Fani

Golshan

Saghaian-nejad

2010

Euro. Trans. Electr. Power

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SUMMARYThis paper uses different geometrical structure of inrush current with respect to that of fault current for the identification of transformer magnetizing inrush. For this purpose, the differential current is considered as a stochastic signal, and a scheme based on stochastic analysis of differential currents is proposed. The scheme converts changes in slope of inrush and fault currents as a major feature of difference between them into a quantitative description by using the skewness concept of frequency curves. Skewness is the degree of asymmetry of a curve, usually taken relative to a normal curve. Internal faults are discriminated from inrush conditions by investigating the signs of the skewness coefficients corresponding to three-phase differential currents. Various experimental cases verify the dependability, security, and fast operation of the proposed algorithm.

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A current-based solution for transformer differential protection. I. Problem statement

Cited by 108 publications

References 21 publications

Enhancement of auxiliary overcurrent protection in transformers using novel feature extraction algorithms

Enhancement of auxiliary overcurrent protection in transformers using novel feature extraction algorithms

A runs test‐based method for discrimination between internal faults and inrush currents in power transformers

A frequency curves analysis-based method for transformers differential protection

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