A new ultra high-speed protection scheme is proposed in this paper. Using wavelet transform with multiresolution analysis, the current signals is decomposed into a series of detailed wavelet components. The spectral e...
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ISBN:
(纸本)9810544693
A new ultra high-speed protection scheme is proposed in this paper. Using wavelet transform with multiresolution analysis, the current signals is decomposed into a series of detailed wavelet components. The spectral energies of the wavelet components are calculated and then employed to detect the faults. Characteristics of the proposed ultra high-speed protection algorithm are analyzed and results of simulation studies are given. The results show that the proposed algorithm is promising and easy to implement for computer relaying application.
A new method, which integrates the virtue of the probability and mathematical statistics with that of the fuzzy mathematics for power quality assessment, is proposed in this paper. The index showing an aspect of power...
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A new method, which integrates the virtue of the probability and mathematical statistics with that of the fuzzy mathematics for power quality assessment, is proposed in this paper. The index showing an aspect of power quality is evaluated using probability and mathematical statistics respectively; the global unique index of these indexes can be obtained. The results obtained from each index unified are unified again using fuzzy synthetic appraisal in order to give an objective, overall and unique index of power quality. The special assessment method for voltage sag using the average sag energy index is also discussed. Finally, a transaction mode makes the maximum benefits for different unit commitment as objective function and takes the power quality into account is presented, and then power energy really becomes a commodity which would be evaluated a price according to power quality
Condition-Based Maintenance is an advanced maintenance strategy which is based on the monitoring of equipments status and according to the results of monitoring and analysis people can arrange maintenance scientifical...
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power quality becomes an emphasis of related researches. Based on the detailed study on QCC (Quality control Center) of the FRIENDS first advanced by Japanese scholars, the functions of QCC are expanded and Its basic ...
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Based on mathematical morphology and grille fractal, a novel approach on power quality disturbance detection and location is presented in this paper. At first a parallel composite morphological filter with multiple-st...
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This paper presents an integrated framework for the optimal management of electricity purchase allocation and risk for load service entities (LSEs). To the practice of China power Markets, we propose the framework of ...
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The dynamic voltage restorer (DVR) has become popular as a cost effective solution for the protection of sensitive loads from voltage problems such as sags. There are many investigations on DVR dealing with the unbala...
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ISBN:
(纸本)9810557027
The dynamic voltage restorer (DVR) has become popular as a cost effective solution for the protection of sensitive loads from voltage problems such as sags. There are many investigations on DVR dealing with the unbalanced operation situations, however, few found in the area relating to DVR self zero sequence component control in power grid with different neutral point grounded modes. In fact, incorrect control strategy of zero sequence will lead DVR to instability in a special system condition. This paper studies the generating mechanism of self zero sequence component in systems with different neutral point grounded modes and presents effective control strategy to get rid of its influence. Simulations are carried out to verify the validity of proposed self zero sequence component control strategy
High current of HVDC grounding electrode will induce a high potential in the nearby substation ground grid if the soil resistivity is high. Once there are potential differences among the ground grids, direct current w...
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High current of HVDC grounding electrode will induce a high potential in the nearby substation ground grid if the soil resistivity is high. Once there are potential differences among the ground grids, direct current will flow through the neutral grounded transformer. If the direct current through transformer winding is high enough core saturation will occur. The paper presented a method of series of additional resistance between the transformer neutral point and ground grid from the point of view of network configuration. A novel optimized algorithm is adopted in order to calculate the grounding resistance. Method presented in the paper is tested with China South Grid data. Results show that current through transformer neutral point can be reduced greatly and thus core saturation can be avoided
This paper puts forward a novel topology of controllable reactor, the structure is based on many small capacity thyristor controlled reactor (TCR) modules and a three-windings transformer connecting to system. The tra...
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This paper puts forward a novel topology of controllable reactor, the structure is based on many small capacity thyristor controlled reactor (TCR) modules and a three-windings transformer connecting to system. The transformer secondary adopts duplex winding structure and each has multi-bank TCR modules being in delta connection. In this topology, the harmonic current injected into the powersystem is very small. It not only possesses all the functions a traditional TCR has, but also has many other merits such as occupying small floor space, generating little loss, easy implement control and protection scheme, and high reliability etc. A 500 kVar industrial prototype is under construction in Langfang, Hebei province of ***. Digital simulation based on EMTDC/PSCAD and field test were carried out to verify the perfect harmonics characteristics of topology proposed
A new load detection method was presented based on its running status of powersystem. The loads are sorted according to their index of capacitive, inductive, and none-linear. The static character of each load was got...
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