Oriented to wye-delta connected three phase transformer, a new configuration of current transformer (CT) in transformer differential protection is proposed. In this configuration, only one single phase CT connected in...
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Oriented to wye-delta connected three phase transformer, a new configuration of current transformer (CT) in transformer differential protection is proposed. In this configuration, only one single phase CT connected in any phase of the delta side is more needed than the traditional scheme. Worked with line currents measured by other current transformers connected in both sides of the transformer, any phase current in the delta side can be calculated based on the Kirchhoff's Current Law. This new scheme ensures the accurate calculation of the equivalent instantaneous inductance, which is immune to the loop current existed in the delta side of transformer, as well as no dead zone in transformer differential protection. A new algorithm based on the distribution of the normalized equivalent instantaneous inductance for the discrimination between inrush current and fault current is proposed. The normalization of equivalent instantaneous inductance makes the setting-value have little relation with the parameter of transformers, which has more universal meaning in the determination of setting values. Utilizing the distributive characteristic of the normalized equivalent instantaneous inductance, the variety of the normalized equivalent instantaneous inductance is effectively revealed. At last, experiment data obtained from HYBRISIM (Hybrid Simulator) validates the reliability and sensitivity of this algorithm. This algorithm has good prospect of engineering application in the EHV transformer protection.
Unbalanced element brings a big problem to fault analysis of symmetrical components method. According with fault analysis of phase components, a residual voltage transformation method for short-circuit current calcula...
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Unbalanced element brings a big problem to fault analysis of symmetrical components method. According with fault analysis of phase components, a residual voltage transformation method for short-circuit current calculation is presented with matrix translation in the place of classical sequence networks connection, which is suitable for both phase coordinates and symmetrical components coordinates. Calculation formulas are proposed with matrices calculation to deal with unsymmetrical faults and parameter matrices for various faults are listed. Analysis of simultaneous faults with unbalanced parameter element is done without calculation qualities increased. Simple examples have shown that the method is practical and suitable for programming.
Electromagnetic interference (EMI) on secondary dc cable in cable tunnel due to a direct lightning strike in substation threatens the safe operation of electronic equipment and system connected to the cable. In order ...
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An improved subcell model is presented for including thin material sheets method in the finite-difference time-domain (FDTD) method. This improved subcell can be used to simulate a thin magnetic (μs ≠ μo) sheet. Th...
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An improved subcell model is presented for including thin sheets in the finite-difference time-domain (FDTD) method. This improved subcell model can simulate thin multilayer material sheets and was verified by compari...
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TheAsiaInformationRetrievalSymposium(AIRS)wasestablishedbytheAsian information retrieval community after the successful series of Information - trieval with Asian Languages (IRAL) workshops held in six di?erent locati...
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ISBN:
(数字)9783540318712
ISBN:
(纸本)9783540250654
TheAsiaInformationRetrievalSymposium(AIRS)wasestablishedbytheAsian information retrieval community after the successful series of Information - trieval with Asian Languages (IRAL) workshops held in six di?erent locations in Asia, starting from 1996. While the IRAL workshops had their focus on inf- mation retrieval problems involving Asian languages, AIRS covers a wider scope of applications, systems, technologies and theory aspects of information retrieval in text, audio, image, video and multimedia data. This extension of the scope re?ects and fosters increasing research activities in information retrieval in this region and the growing need for collaborations across subdisciplines. We are very pleased to report that we saw a sharp increase in the number of submissions and their quality, compared to the IRAL workshops. We received 106papersfromninecountriesinAsiaandNorthAmerica,fromwhich28papers (26%) were presented in oral sessions and 38 papers in poster sessions (36%). It was a great challenge for the Program Committee to select the best among the excellent papers. The low acceptance rates witness the success of this year’s conference. After a long discussion between the AIRS 2004 Steering Committee and Springer, the publisher agreed to publish our proceedings in the Lecture Notes in Computer Science (LNCS) series, which is SCI-indexed. We feel that this strongly attests to the excellent quality of the papers.
To improve the computation accuracy of the transient radiation fields in gas insulated substation (GIS), surface-patch model is proposed in this paper, and the method of vector fitting combining with recursive convolu...
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In order to research the transient current and voltage along the busbar in substations, the ground return impedance of aerial multiconductor transmission lines above a multilayer soil is researched and its time-domain...
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