This paper presents a Multi-Agent and WAN Based Adaptive Coordinated protectionsystem (MAWBACPS). The system utilizes IP Intranet to realize real-time wide area information exchange of a powersystem. Multi-agent sys...
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The paper studies a practical project of 2MVA dynamic Voltage Restorer on the basis of transformer-less cascade multilevel topology, it discusses each part working principle of DVR, but also provides a practical volta...
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In order to implement real time detection of harmonic voltage, a method for any harmonic voltage detection based on instantaneous reactive power theory was presented. In the detection the standard current signals were...
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In order to implement real time detection of harmonic voltage, a method for any harmonic voltage detection based on instantaneous reactive power theory was presented. In the detection the standard current signals were additional, so the detection precision was not affected by the distorted system current and the detection results could also reflect the changes of frequency shift. To make the dynamic response speed quicker, an algorithm with feedback compensation was presented. The simulation results show that the algorithm can quicken the dynamic response speed effectively, the feedback compensation value also has a bigger effect on the response speed and detection precision, and the detection performance are not affected by frequency shift.
Along with the increment of disturbing loads in the powersystem, the effect on network that is brought by the power quality problems, become increasingly serious. Based on the market bargaining principles, the power ...
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The reflection and refraction of fault-generated wave on EHV lines were investigated and the equations of transient current detected by relay were deduced. Theoretical analysis shows that the protection based on the e...
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The reflection and refraction of fault-generated wave on EHV lines were investigated and the equations of transient current detected by relay were deduced. Theoretical analysis shows that the protection based on the energy ratio of higher frequency components is more adaptive to various faults and can distinguish between the internal and external faults near the remote busbar more effectively. Such protection also has similar performance when used on EHV lines and series compensated EHV lines. The wavelet packet transform technique was employed to determine the energy ratio. Simulation results show that the proposed conclusions are correct.
To avoid the mal-operation of transformer differential protection when out-zone fault occurs under current transformer (CT) saturation, a new algorithm based on the mathematical morphology is put forward in this paper...
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To avoid the mal-operation of transformer differential protection when out-zone fault occurs under current transformer (CT) saturation, a new algorithm based on the mathematical morphology is put forward in this paper. Unlike the traditional time-differential method, which is based on the time difference between fault occurrence and the differential current increase, this algorithm only needs detecting the time of fault occurring, while the time of differential current increasing is no more needed. A new current waveform is obtained by a symmetrical transformation of the initial part of differential current after fault occurred, and then its characteristic is extracted by morphological gradient. In the case of CT's serious saturation, a discrimination of out-zone fault and inner-zone fault can be clearly made by this algorithm, which needs a little calculation and a short data window. Simulation results of EMTP validate its feasibility and reliability.
A method of powersystem cascading outages assessment based on support vector machine (SVM) was provided in this paper. Taking full advantages of the ability of SVM to solve the problem with small sample, nonlinear an...
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A method of powersystem cascading outages assessment based on support vector machine (SVM) was provided in this paper. Taking full advantages of the ability of SVM to solve the problem with small sample, nonlinear and high dimension, this method constructs an assessment mode which uses resampling classification technique based on boosting method, pretreatment technique based on distance criterion and information fusion technique. This mode can help to improve the precision and stability of assessment, hence better generalization ability of assessment is guaranteed. At the end of this paper, an example is provided to demonstrate the validity of the proposed approach.
Attributes are require to be discrete when using data mining methods to establish forecasting model, for example, rough set, ANN and decision tree. But most discrete methods used before can't consider the relation...
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Attributes are require to be discrete when using data mining methods to establish forecasting model, for example, rough set, ANN and decision tree. But most discrete methods used before can't consider the relationship of conditional and decision attributes well, so the discrete results are not very satisfaction. This paper presents a new discrete method which combines clusters and entropy. First, cluster is adopted to get the waiting breakpoints. Then finally results are decided by their rate of entropy. According to clustering, the boundary value is greatly reduced. Meanwhile, through entropy which considers the condition attributes and decision attributes, attributes can be discreted more exactly. At last, the discrete results compared with the method based on the importance of breakpoints show that the proposed method assurance the quality of classing. The space of sample can be compressed effectively, which lightens the training load of model and the gotten rules are with good adaptability and useful value. The correctness and effectiveness are validated by the practical application and the accuracy of forecasting will be increased.
Restoration of a powersystem after a complete blackout is a very important issue to the safety of the powersystem. Reasonable black start schemes arc necessary to restore the powersystem as soon as possible. Based ...
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In electricity market, it is widely accepted that short-term load forecast is a key problem of market operation. In this paper, a novel model for load forecasting based on Intelligence Information Processing is presen...
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ISBN:
(纸本)9810544693
In electricity market, it is widely accepted that short-term load forecast is a key problem of market operation. In this paper, a novel model for load forecasting based on Intelligence Information Processing is presented. Here, we make full use of the excellent property reconstruction ability of independent component analysis, which is a new intelligence information processing technology for separating signals and making them independent mutually, and presents STLF model based independent property reconstruction. The load properties of different kinds are restructured to enhance its representation ability and simplifying STLF modeling by ANN. After neural network is trained by new properties with lower dimension, STLF model is built. Finally, the real load data of spot market in New England is applied to demonstrate the validity of the proposed approach.
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