Chongqing Jiangbei Power Supply Bureau

Chongqing, China

Chongqing Jiangbei Power Supply Bureau

Chongqing, China
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Lei Y.,Tsinghua University | Lei Y.,Chongqing Jiangbei Power Supply Bureau | Zhao Z.,Tsinghua University | Yuan L.,Tsinghua University | Lu S.,Tsinghua University
Dianli Xitong Zidonghua/Automation of Electric Power Systems | Year: 2012

LCL filters are increasingly used in grid-connected photovoltaic inverters as the preferred option. Its inherent resonance character makes the damping strategy a hot topic for research. LCL filter, inverter and the grid are modeled and studied as a whole. The commonly used virtual resistor method of passive and active damping, the impacts of inverter's behavior and the grid stiffness on the damping effect are studied in detail. The results show that the non-ideal characteristics of the grid, the proportional gain and the control delay affect the damping properties the most. A hybrid damping method combining active and passive damping is proposed. The method can reduce the impact of control delay and is adaptable for grid change. Experimental results show its effectiveness. © 2012 State Grid Electric Power Research Institute Press.


Yao C.-G.,Chongqing University | Zhou D.-B.,Chongqing University | Chen P.,Chongqing University | Chen P.,Chongqing Jiangbei Power Supply Bureau | And 2 more authors.
Gaodianya Jishu/High Voltage Engineering | Year: 2011

We researched the UHF-based method for PD monitoring of electrical equipment in the substation, which could use a fixed antenna array and relevant corollary equipment to monitor PD for the whole substation and to achieve early warning. Omnidirectional antenna array was placed in the centre of substation to receive UHF signals triggered by faulted equipment in substation space, PD existing in substation could be detected and the electrical equipment with PD could be found according to the measured signals. Thereby, we built a monitoring system with wideband, good gain and horizontal plane omnidirectional disc-cone antenna as UHF sensor, in the substation test, system detected the discharge signals and discharge source in disconnector were located by the signals. The site measurement results prove that this is a useful method for PD monitoring of the whole substation and early warning.


Feng W.,Chongqing University | Liu G.,Chongqing University | Liao Y.,Chongqing Jiangbei Power Supply Bureau | Zhao W.,Chongqing University
Journal of Information and Computational Science | Year: 2013

Clustering is an efficient way of network topology management, and the hierarchical structure obtained by clustering algorithm can largely improve the performance of Mobile Ad Hoc Network (MANET). To better accommodate MANET, we propose a Multi-parameter Weighted Clustering (MWC) algorithm which takes into consideration three parameters: residual power, connectivity, and average mobility. We also designed different average mobility parameter for two typical MANET models, that is, Relative Stability (RS) for Random Walk Mobility (RWM) networks and Moving Correlation (MC) for Reference Point Group Mobility (RPGM) networks. Simulation results showed that the proposed algorithm has a better performance than HD and MOBIC in three aspects: topology simplicity, environment adaptability, and cluster stability. © 2013 Binary Information Press.


Lu Z.,Chongqing University | Liu J.,Chongqing University | Zheng L.,Chongqing University | Ma Z.,Chongqing University | And 2 more authors.
Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering | Year: 2010

A novel input-series output-series high gain Boost converter was proposed in this paper. Operation principle and property of this converter were analyzed. The new topology was composed of two identical high gain subtopologies with input-series and output-series connection. As the Cf1 and Cf2, the new topology not only had high voltage gain, but also automatically evenly could share current without any sensing when the duty cycle was greater than or equal to 0.5. Compared with the traditional two phase interleaved Boost converter, the ripple of the inductor current, the ripple of the input current and the voltage stress of the switches were reduced because of the double-series structure of the new topology. Consequently, the new topology is very suitable for the application (for example, the fuel cell power system) in which it has low input voltage but high output voltage. Finally, the experiment was built to verify the theoretical analysis. © 2010 Chinese Society for Electrical Engineering.


Tang J.,Chongqing University | Xie Y.,Chongqing University | Zhang X.,Chongqing University | Zhou Q.,Chongqing Jiangbei Power Supply Bureau
Gaodianya Jishu/High Voltage Engineering | Year: 2012

Radio frequency (RF) measurement has become a hot issue for partial discharge detection. However, its application is hampered by the difficulty to establish a relationship between the RF measurements data and apparent discharge quantity. In this paper, on the basis of an experimental model of metal protrusion, the relationship between the results of RF measurement and pulse current method (IEC 60270) was investigated. The energy, double integration, peak voltage, peak-peak voltage and the area of RF signals were plotted versus either the apparent discharge quantity or the square of the apparent discharge quantity in order to evaluate the optimal regression curve. At the same time, the impact of voltage and the distance between protrusion and plate were also investigated. The results indicate that the optimal match to a linear regression curve can be gained by plotting the RF signal energy versus the square of the apparent discharge quantity. The variation of voltage has no significant impact on the regression curve; that is, data from different voltages match one line. However, when the distance between protrusion and plate is changed, the slope of the regression curve changes accordingly; the same energy corresponds to a bigger discharge quantity. The results are significant enough to be applied in the estimation of the discharge quantity by measuring RF partial discharge signals.


Xie Y.,Chongqing University | Tang J.,Chongqing University | Zhou Q.,Chongqing Jiangbei Power Supply Bureau
European Transactions on Electrical Power | Year: 2010

Ultra-high-frequency (UHF) partial discharge (PD) detection is an effective means for evaluation of dielectric condition of gas insulated switchgear (GIS). Time-resolved data pattern is utilized to recognize insulation defect because of its attractive advantages that there exists some direct relationship between the shape of PD signal and the physics of the defect. Therefore, the main task is feature extraction of time-resolved data. However, it is hard to extract features in time domain because there is no obvious difference in types of signals. UHF PD signals are non-stationary, so feature extraction in frequency domain is not suitable as well. Feature extraction in time-frequency domain based on discrete wavelet transform (DWT) is a solution for this problem, but there is a weak point which hampers the application of this method, that is, lack of shift invariance, which means that small shifts in the input signal can cause major variations in the distribution of energy between DWT coefficients at different scales. In this paper, a new method of feature extraction of UHF PD signal on the basis of dual-tree complex wavelet transform (CWT) which can reduce shift sensitive is proposed. UHF PD signals are acquired in lab and decomposed by a dual-tree CWT. Then the feature space is constructed through the energy on all frequency bands and modulus maxima on all scales. At last feature space is inputted into a radial base function (RBF) neural network classifier. The results show the superiority of this method over traditional ones. Copyright © 2009 John Wiley & Sons, Ltd.


Xie Y.,Chongqing University | Tang J.,Chongqing University | Zhou Q.,Chongqing Jiangbei Power Supply Bureau
European Transactions on Electrical Power | Year: 2010

Online partial discharge (PD) detection still remains a very challenging task because of the strong electromagnetic interferences. In this paper, a new method of de-noising, using complex Daubechies wavelet (CDW) transform, has been proposed. It is a relatively recent enhancement to the real-valued wavelet transform because of two important properties, which are nearly shift invariant and availability of phase information. Those properties give CDW transform superiority over other real-valued wavelet transform. On the basis of CDW transform, complex threshold algorithm and combined information are devised. In order to take into account the difference of the real part and imaginary part of complex wavelet coefficients, complex threshold is devised to modify the real part and imaginary part respectively. Because the restored signal by inverse CDW transform is complex one, combined information is devised to combine the real part and imaginary part of complex signal to construct a real one, furthermore making full use of the simple information from complex signal. Copyright © 2009 John Wiley & Sons, Ltd.


Tang J.,Chongqing University | Xie Y.,Chongqing University | Zhou Q.,Chongqing Jiangbei Power Supply Bureau | Zhang X.,Chongqing University
Diangong Jishu Xuebao/Transactions of China Electrotechnical Society | Year: 2010

Ultra-high frequency (UHF) method has been widely used for partial discharge (PD) detection in gas insulated switchgear (GIS), but the feature extraction for UHF PD signals is a difficult issue all the while. In this paper, a method using wavelet packet transform (WPT) is proposed to decompose the UHF PD signals, and the best basis is selected using minimum entropy criterion based on UHF PD mathematical model of four typical defects in GIS, then the energy in each frequency range, maximal values of module and absolute average values in each scale are computed according to WP coefficients, and the features space is constructed integrally; Kernel principal component analysis (KPCA) is also proposed for reducing dimension of features, and dimension crisis is resolved well, and the divergence matrix strangeness in every class is eliminated. At the same time, the characteristics of signals are retained the farthest. The classification results show that the features used in this paper are quite well for UHF PD defect identification.


Hu N.,University of Sichuan | Li X.,University of Sichuan | Li K.,University of Sichuan | Mu Z.,Chongqing Jiangbei Power Supply Bureau | Zhu R.,University of Sichuan
Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering | Year: 2013

With the rapid development of synchrophasor based wide area monitoring systems (WAMSs), measurements from the phasor measurement units (PMUs) can be used for online identification of the low frequency oscillations in power systems. To solve the problem that colored Gaussian noise produced by low pass filters may impact the accuracy of oscillation mode indentification, this paper proposed a modified matrix pencil method based on fourth-order mixed mean cumulant (FOMMC) for oscillation mode identificaion. Substituting the sampled signal by its fourth-order mixed mean cumulant sequence along the diagonal line, the method can reduce the impact of the noise effectively. The simulation result shows using the proposed method, the dominant oscillation modes can be identified in the environment with additive colored Gaussian noise. © 2013 Chinese Society for Electrical Engineering.


Mu Z.,Chongqing Jiangbei Power Supply Bureau | Li H.,Chongqing Jiangbei Power Supply Bureau | Li Z.,Chongqing Jiangbei Power Supply Bureau
Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering | Year: 2014

Taking the fast controllability of HVDC system into consideration, the model of supplementary subsynchronous oscillation damping controller (SSDC) on the basis of proportional-integral-derivative (PID) control was established to solve the potential sub-synchronous oscillation (SSO) problem in the sending end of ultra-high voltage direct current (UHVDC) transmission system from Xiangjiaba to Shanghai. A new method which combining mini-max value principle and improved particle swarm algorithm together is put forth so that the parameters of the controller could be designed and optimized conveniently. The time domain simulation results of different operation modes show that the SSDC designed is with strong robustness and can effectively restrain the shaft torsional vibration of steam turbine units. ©2014 Chin. Soc. for Elec. Eng.

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