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Wang X.,CAS Shenyang Institute of Automation | Wang X.,University of Chinese Academy of Sciences | Yang Z.,CAS Shenyang Institute of Automation | Wang Y.,Shenyang Power Supply Company | Wang Z.,CAS Shenyang Institute of Automation
Yi Qi Yi Biao Xue Bao/Chinese Journal of Scientific Instrument | Year: 2013

This paper proposes a dual extended Kalman filtering (DEKF) algorithm for estimating the State-of-Charge (SOC) of lithium-ion batteries on line. First of all, the state-space representation of the battery model is established based on Thevenin battery model and Kalman filtering algorithm. The least squares method and the DEKF algorithm are used to identify the battery model parameters, which improves the model accuracy and facilitates the battery model to well reflect the actual internal state of the battery. Moreover, the principle of using DEKF algorithm to estimate the inner SOC of the battery on line is introduced, and corresponding battery test experiments are designed. Experiment results demonstrate that under various operating conditions, the algorithm has relatively high accuracy and good environment adaptability when applied to evaluate SOC on line; and the maximum error is less than 4.5%. The DEKF algorithm is proved to have good convergence and robustness, and can efficiently solve the problems of inaccurate initial-value estimation and error accumulation. Source


He X.H.,Beijing Jiaotong University | Wang W.,Beijing Jiaotong University | Wang Y.N.,Shenyang Power Supply Company | Kong J.,Liaoyuan Power Supply Company | And 2 more authors.
Applied Mechanics and Materials | Year: 2014

According to the problem of optimal power flow (OPF), the optimization objectives including minimization of total fuel cost for generating units, minimization of emission for atmospheric pollutants, minimization of active power losses and minimization of voltages deviations are established. The paper uses fuzzy membership functions instead of multi-objective functions to form fuzzy optimal power flow in the optimal power flow calculation process. The novel artificial bee colony (ABC) algorithm is proposed to solve OPF problem with multi-objective. The proposed approach is applied to the OPF problem on IEEE30 test systems. And the simulation results verify the effectiveness of the proposed method. © (2014) Trans Tech Publications, Switzerland. Source


Zheng T.,North China Electrical Power University | Pan Y.,North China Electrical Power University | Guo K.,Shenyang Power Supply Company | Wang Z.,North China Electrical Power University | Sun J.,North China Electrical Power University
Dianwang Jishu/Power System Technology | Year: 2013

A nodal impedance matrix based improved fault location algorithm for distribution network is proposed. The topological structure and parameters of distribution network will change after the fault and it leads to the change in nodal impedance matrix, in other word, the post-fault nodal impedance matrix in which the unknown fault distance and transition resistance are involved, is formed, thus based on physical meaning of nodal impedance the expression of fault location can be established. For the proposed algorithm, only current and voltage of substation outgoing line are needed as the input variables, and the voltage and current of the bus located at the upstream of the faulty zone can be calculated by iteration, and substituting the calculation results into the established fault location expression the fault distance and transition resistance can be solved. To suit the features that the load characteristics in distribution network are time-varying and not unified, it is put forward that the load in distribution network is simulated by the static voltage characteristic based load model, and adopting such a model the post-fault loads and the shunts in branches can be calculated more accurately to make the result of fault location more accurate; it is also put forward that combining with the feeder automation function of distribution network the number of pseudo fault points can be reduced and it is helpful to fault location. A model of IEEE 34-bus distribution system is constructed by PSCAD, and the proposed fault location algorithm is implemented in Matlab-based environment. Simulation results show that the proposed fault location algorithm is effective. Source


Liu X.,Northeastern University China | Fu Q.,Northeastern University China | Sun Q.,Northeastern University China | Zhang Y.,Northeastern University China | Wang Y.,Shenyang Power Supply Company
Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering | Year: 2015

This paper analyzes the influence factors of natural disasters playing on power grid from the perspective which is responding to emergencies and power grid blackout accident caused by disasters. The evaluation index system is established in view of the fuzziness and uncertainty of influence factors. A novel disaster assessment approach based on intuitionistic fuzzy rough sets is presented. It can make a timely and accurate assessment of grid disaster, identify the level of disaster and update along with the development of the situation to provide the scientific basis for the emergency decision-making. In this paper, attribute reduction is used to reduce redundancy of disaster's attributes, and value reduction is used to extract the evaluation rules. It is proved that it's available for using intuitionistic fuzzy rough sets to assess for grid disasters by exemplifying the grid disaster's assessment of snow disaster in Liaoning province, and the visualization system of disasters evaluation is realized using software design. The research which is to improve the ability of responding to natural disasters emergency response and to resist risks is of great significance. © 2015 Chin. Soc. for Elec. Eng. Source


Yao Y.-H.,North China Electrical Power University | Wang Z.-P.,North China Electrical Power University | Guo K.-Y.,Shenyang Power Supply Company | Jin P.,Shenyang Power Supply Company
Dianli Xitong Baohu yu Kongzhi/Power System Protection and Control | Year: 2014

The classic multi-objective evolutionary algorithm based on Pareto dominance criteria and crowding distance sorting method does not consider the preference of decision maker in the iterative process, which leads to the decline of convergence performance. For the problem, this paper proposes a multi-objective binary particle swarm optimization based on E-dominance to solve distribution network service restoration. By adopting E-dominance strategy of improving the origin distance, it can integrate the preference of decision makers into the evaluation process. This paper adopts roulette strategy to update the global best solution and integrated value to maintenance the external files, which can effectively guide the next generation of particle with preference of decision makers during iterative process. Finally, an example shows that the approach has better convergence performance, less quantity and better quality on solution than the classic multi-objective algorithm based on Pareto dominance criteria and crowding distance. ©, 2014, Power System Protection and Control Press. All right reserved. Source

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