Guangxi Power Grid Corporation

Nanning, China

Guangxi Power Grid Corporation

Nanning, China
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Liu Y.-N.,Guilin University of Electronic Technology | Zhong Q.,Guilin University of Electronic Technology | Xie M.,Guangxi Power Grid Company | Chen Z.-B.,Guangxi Power Grid Company
Multimedia Tools and Applications | Year: 2017

In this paper, a novel multiple-level secret image sharing scheme is proposed, which achieves the additional steganography, the authentication, and the scalable abilities. The key idea is that the secret image is revealed at different quality levels with the different priorities. Specifically, based on the weight function and Shamir’s secret sharing, the meaningful shadow images are distributed among the different level participants, and the participants with the higher priority are capable of revealing more information about the secret image. Meanwhile, the proposed scheme enables the cover images to be losslessly restored. Besides, the secret image can be progressively revealed when more participants of the different levels cooperate together. Moreover, the verifiable correctness of the shadow images prevents from cheating among the participants before the recovery of the secret image. © 2017 Springer Science+Business Media New York


Bao H.,Guangxi University | Bao H.,Guangxi Power Grid Corporation | Wei H.,Guangxi University | Guo X.,Guangxi University
Dianli Zidonghua Shebei/Electric Power Automation Equipment | Year: 2016

The wind power generation unit with DFIG (Doubly-Fed Induction Generator) has a certain capability of reactive voltage regulation when it operates in constant voltage mode. In order to precisely evaluate the voltage stability of power system with DFIG and obtain more accurate statistical information of critical power or load margin, a probabilistic evaluation model of static voltage stability is constructed, which considers the reactive power limit of DFIG operating in constant voltage mode and combines Monte Carlo method with interior point method to obtain the solution. The model takes the connecting node of wind farm as a PV node and considers the injecting reactive power of grid-side converter. The impacts of wind speed randomness and correlation on the injecting reactive power of DFIG and the voltage stability of system are analyzed. The calculated results for IEEE 118-bus and 300-bus systems indicate the proposed model and method are effective. © 2016, Electric Power Automation Equipment Press. All right reserved.


Shen C.,Tsinghua University | Wu X.-Y.,Tsinghua University | Wang Z.-W.,Tsinghua University | Zhao M.,Tsinghua University | Huang X.-Q.,Guangxi Power Grid Corporation
Dianli Xitong Baohu yu Kongzhi/Power System Protection and Control | Year: 2014

Microgrid has attracted attentions both in academia and industry in recent years because it can effectively utilize the distributed resources and enhance the reliability of distribution networks. This paper summarizes the experiences obtained from several practical projects, and rethinks about the remaining technological difficulties and possible solutions in the development and operation of microgrids, such as stability control, protection, planning and so on. An outlook of future development of microgrids is also proposed.


Tian P.,Tsinghua University | Tian P.,Wuhan Naval University of Engineering | Xiao X.,Tsinghua University | Ding R.,Tsinghua University | Huang X.,Guangxi Power Grid Company
Dianli Xitong Zidonghua/Automation of Electric Power Systems | Year: 2013

In view of the autonomous multi-microgrid (MMG) and its submicrogrid capability of off-grid operation plus steady operation in extreme conditions, an analysis is made of the characteristics of variation of accumulated unbalanced power in the MMG and submicrogrid with time parameters, including submicrogrid maximum allowable off-grid operation time, MMG maximum allowable off-grid operation time and expected maximum operation time with failure of submicrogrid and MMG. In order to ensure that the energy-type storage can compensate for the maximum insufficient energy and absorb the maximum surplus energy and the power-type storage can inhibit the maximum power fluctuation in the system, a capacity configuring method for the energy storing and power storing for MMG is proposed. For the given index of maximum allowable off-grid operation time and expected maximum operation time with failure of microgrid and MMG, the method can calculate the minimum size of composite energy storage systems (CESS) without massive time-domain simulation. Simple and convenient to use, the method has been used to improve the stability of MMG located at Weizhou island in Guangxi province. It is proved by calculating the load power loss probability that the capacity configuration can meet the system's requirement for reliability. © 2013 State Grid Electric Power Research Institute Press.


Wei H.,Guangxi Power Grid Company | Zhou D.,Harbin Institute of Technology | Wang Y.,Harbin Institute of Technology
Dianli Xitong Baohu yu Kongzhi/Power System Protection and Control | Year: 2011

On-line parameter measurement of double-circuit transmission lines based on fault recorder is presented, in order to measure the transmission line's parameter conveniently. The theory of double-circuit transmission lines' positive sequence parameter measurement and zero sequence parameter is described. The process of transmission line online measurement is introduced. Fault recorder connected with GPS is used as the synchronization data collection device. Transmission line's parameter is calculated by center computer. The simulation results prove that the new method can meet the needs of live line measurement.


Long D.,Guangxi University | Long D.,Guangxi Power Grid Corporation
China International Conference on Electricity Distribution, CICED | Year: 2014

We address the problem of security constrained unit commitment (SCUC) with power flow constraints, capturing the uncertainty of wind power and demands. We propose a modeling and algorithmic strategy based on the framework of approximate dynamic programming (ADP). A stochastic optimization model is developed for the SCUC problem with power flow constraints. We demonstrate the methodology using both stochastic and deterministic formulations of the SCUC problem. Th is paper describes the handling of power flow constraints and different sources of uncertainty. The application on IEEE-30 to -300 bus systems and a Polish-2737 bus test system fully validate the effectiveness of the ADP-based modeling and algorithmic strategy. © 2014 IEEE.


Cai H.-M.,Guangxi Electrical Power Institute of Vocational Training | Chen J.-Y.,Guangxi Power Grid Corporation | Su H.-Y.,Guangxi University
Dianli Xitong Baohu yu Kongzhi/Power System Protection and Control | Year: 2012

In order to improve the diagnosis ability of dissolved gas analysis, a novel method for the power transformer fault diagnosis based on gray cloud model is proposed. Softening factor is introduced via entropy theory, and the classification limit single value for canonical matrix of the power transformer fault diagnosis is transformed into the concept of interval numbers limit value. The gray cloud model is used to reflect the fuzziness and randomness of the classification limit value for the power transformer fault diagnosis, which is composed of the peak value, the boundary value of left and right endpoint, the entropy, and the hyper entropy. The subjectivity of the diagnosis results is effectively reduced by establishing the importance information unascertained rational numbers of indicators for the power transformer fault diagnosis, through which the weight value of each index is obtained. A gray clustering algorithm based on gray cloud whitening weighting function is used to analyze and judge the fault pattern of the power transformer. The actual numerical example results show that the proposed method has high degree of diagnosis accuracy, and is characterized by fast diagnosis and good real-time, demonstrating the model is practical and effective.


Liu Y.,Chongqing University | Zhou L.-W.,Chongqing University | Chen G.-T.,Guangxi Power Grid Company
Dianli Xitong Baohu yu Kongzhi/Power System Protection and Control | Year: 2011

Aiming at the complex stage difference coordination in DC system, the model of DC system protection device and the algorithm of stage difference coordination are analyzed, and the system of DC protection system state detection and maintenance decision is designed. At first, according to the ampere-second characteristics of protective devices, the model of the protective device is simplified and improved on the original basis. Secondly, according to the wiring diagram, measured load current, parameters of feeders and ampere-second characteristics of protective devices of one 220 kV transformer substation DC system, the stage difference coordination status when different kinds of short circuit occur is simulated, reasons for possible leapfrog are found, and the rationality of selection of protective devices is analyzed. Finally, reasonable maintenance decisions of protective devices are proposed by applying the system of DC system protective devices state detection and maintenance decision. The method proposed in this paper is unniversal and has a good operability, which can guide the design and technological improvement of DC system.


Zeng J.-M.,South China University of Technology | Bai X.-H.,Guangxi Power Grid Company | Zhang Y.-J.,South China University of Technology | Yang X.-Y.,South China University of Technology
Dianli Xitong Baohu yu Kongzhi/Power System Protection and Control | Year: 2014

Because some remaking measures can reduce the line-loss of the distribution network further and improve the voltage quality, this paper puts forward an assessment method including the energy saving and the voltage quality improving. Firstly, the lines should be classified according to the actual situation of a certain area. Then it picks up several typical lines to the comprehensive energy saving potential in six different remaking measures. At last, it can get the retrofit scheme for each type of the lines according to the ranking value of different measures. It uses the distribution line as an example to assess the comprehensive energy saving potential and puts forward the feasible retrofit scheme.


Chen J.-Y.,Guangxi Power Grid Corporation | Cai H.-M.,Guangxi Electrical Power Institute of Vocational Training | Su H.-Y.,Xiangtan Power Supply Bureau
Dianli Xitong Baohu yu Kongzhi/Power System Protection and Control | Year: 2012

Aiming at many kinds of uncertain information in the power generation system reliability evaluation under the electric power market condition, a power generation system reliability flexible evaluation model which contains evaluation theory, evaluation index, and evaluation method is proposed based on blind number theory. This model uses the blind number to express node information, which effectively deals with the impact of primitive parameter uncertainty on the reliability evaluation. The reliability index's sensitivity formula is used to effectively find the weak link restricting system reliability, and then the reliability cost-benefit assessment for the power generation system is carried out. The numerical example of IEEE-24 buses reliability test system demonstrates the correctness and availability of the proposed approach.

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