Entity

Time filter

Source Type

Shijiazhuang, China

Niu S.,North China Electrical Power University | Liang Z.,North China Electrical Power University | Su H.,North China Electrical Power University | Gao J.,Hebei Electrical Power Institute
2010 China International Conference on Electricity Distribution, CICED 2010 | Year: 2010

With the development of measurement in node voltage, branch current and nodal injection current phasor measurement system (PMU), the phase measurement system provides a new idea for power system's online analysis. For the harmonic state estimation, we mainly use the PMU synchronized sampling which installed in different points of factory, that is, data acquisition device installed in different plants, the sampling time is synchronized to the same time base, which are the data harmonic state estimation required. Set up a simulation system layout the measurement points in a reasonable way, considering the points which measurement voltage and current values as a known quantity, establish a mathematical model. Applying the generalized ridge estimate to solve the mathematical model in order to obtain the harmonic voltage of each node in the system, and then determine the system's harmonic state. © 2010 Chinese Soc for Elec Eng. Source


Yu J.,Tianjin University | Liu K.,Tianjin University | Zhang L.,Tianjin University | Luo P.,Hebei Electrical Power Institute
International Journal of Distributed Sensor Networks | Year: 2015

The second and the third sentences of the abstract are changed and the shorter abstract is given as follows. To recover the nonstationary signal in complicated noise environment without distortion, a novel general design of fractional filter is proposed and applied to eliminate the Wigner cross-term. A time-frequency binary image is obtained from the time-frequency distribution of the observed signal and the optimal separating lines are determined by the support vector machine (SVM) classifier where the image boundary extraction algorithms are used to construct the training set of SVM. After that, the parameters and transfer function of filter can be determined by the parameters of the separating lines directly in the case of linear separability or line segments after the piecewise linear fitting of the separating curves in the case of nonlinear separability. Without any prior knowledge of signal and noise, this method can meet the reliability and universality simultaneously for filter design and realize the global optimization of filter parameters by machine learning even in the case of strong coupling between signal and noise. Furthermore, it could completely eliminate the cross-term in Wigner-Ville distribution (WVD) and the time-frequency distribution we get in the end has high resolution and good readability even when autoterms and cross-terms overlap. Simulation results verified the efficiency of this method. © 2015 Jiexiao Yu et al. Source


Liang Z.,North China Electrical Power University | Niu S.,North China Electrical Power University | Su H.,North China Electrical Power University | Duan X.,Hebei Electrical Power Institute
2010 China International Conference on Electricity Distribution, CICED 2010 | Year: 2010

Based on the wide area measurement system (WAMS), this article proposes Research of flexible wide-area measurement and analysis system in power system(Flexible Wide Area Measurement System, FWAMS). The system can flexible layout several interim measurement points in local Network, and access to Flexible Phasor Measurement Unit (FPMU), According to different time periods and different needs flexible build wide-area synchronized measurement network respectively, Measure the system state. We can use the limited measurement devices measure the whole network state "quasi-total coverage", it can effectively overcome the shortcomings of the fixed network mode of the monitoring system. © 2010 Chinese Soc for Elec Eng. Source


Li B.-Y.,Hebei Electrical Power Institute | Chen X.-D.,Hebei Electrical Power Institute
Dianli Xitong Baohu yu Kongzhi/Power System Protection and Control | Year: 2010

Through analyzing the work principle of AC-injection insulation monitoring and bridge insulation monitoring, the paper expounds the merits and demerits of several monitoring methods. The performance index and functions of the main insulation monitoring device of Hebei south power system are analyzed and the influence scope of balance bridge resistance and switch bridge resistance on the fluctuation and excursion of DC earth ground voltage is calculated. The calibration method for off-line DC system insulation monitoring device is analyzed. It uses different operation conditions of DC grounding calibrator to simulate different grounding faults of DC system and calibrate operation conditions of multi-point grounding, bipolar equilibrium grounding, AC grounding and voltage excursion. The proposed calibration method can regulate the function of insulation monitoring device, and effectively avoid the malfunction of protection device when one-point grounding occurs. Source


Duan X.,Hebei Electrical Power Institute | Gao J.,Hebei Electrical Power Institute | Liang Z.,North China Electrical Power University | Su H.,North China Electrical Power University | Zhou W.,Hebei Electrical Power Institute
2010 China International Conference on Electricity Distribution, CICED 2010 | Year: 2010

In this paper a novel flicker measurement method is proposed after studying the IEC flicker meter. This method need spectral analyze the wave component to calculate the instantaneous flicker sensation level, and then the pisarenko harmonic decomposition (PHD) is used to obtain the amplitude and the frequency of wave components. To process the wave component by PHD can acquire precise spectrums. The IEC flicker meter and novel method is compared in simulation and test. The result verified the correctness and efficiency of the theoretical prediction. © 2010 Chinese Soc for Elec Eng. Source

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