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Zhang Z.,Qingdao University | Wen L.,Liaocheng Electrical Power Company | Li G.,Qingdao University | Zhang W.,Liaocheng Electrical Power Company
Dianwang Jishu/Power System Technology | Year: 2014

To mitigate the impact of fluctuation of renewable generation output on power grid and accelerate the population of electric vehicles (EV), taking the minimized output fluctuation of renewable generation and the maximized income of EV users as objective function and considering the constraints of the electricity quantity stored in the battery, the charging/discharging power and the charging/discharging times, a multi-objective coordinated scheduling model, in which the grid-connectible EV, wind power generation system and photovoltaic (PV) generation system are taken into account simultaneously, is established. A virtual ideal molecular based multi-objective improved chemical reaction optimization algorithm(CROA) is proposed, and the established model is solved by the proposed algorithm. In allusion to such defects of CROA as slow convergence and low accuracy, the update mode of particle swarm optimization algorithm is integrated with the improved CROA. Results of calculation example show that through reasonably arranging the charging/discharging of EV, the output fluctuation of renewable generation can be effectively suppressed and the income of EV users can be increased. Comparison results show that the virtual ideal molecular based improved multi-objective CROA possesses strong searching ability.


Liu Y.,Shanghai JiaoTong University | Sheng G.,Shanghai JiaoTong University | Sun X.,Liaocheng Electrical Power Company | Gao S.,Shandong EHV Power Transmission Company | Jiang X.,Shanghai JiaoTong University
Dianli Xitong Zidonghua/Automation of Electric Power Systems | Year: 2012

The relationship between the transmission line length and the operating states of transmission line, including the conductor temperature, equivalent icing thickness and wind speed, is analyzed based on the equation of state in transmission line. The corresponding method to calculate the transmission line length is also proposed by considering the operating states of transmission line. Correctness of this method is verified by the conductor tension and conductor temperature practical running data from Northeast China. Finally, the conversion equation is established according to relationship between the transmission line length and the operating states of transmission line, and then the actual distance to fault position is converted into the horizontal distance. © 2012 State Grid Electric Power Research Institute Press.


Liu Y.,Shanghai JiaoTong University | Sheng G.,Shanghai JiaoTong University | Shen X.,Shanghai JiaoTong University | Jiang X.,Shanghai JiaoTong University | And 3 more authors.
Proceedings of 2012 IEEE International Conference on Condition Monitoring and Diagnosis, CMD 2012 | Year: 2012

This paper delineates a novel analytical and computational approach to fault location for power transmission grids. The distributed fault location methodology involves three locators installed along the line. The fault section methodology is proposed using the deviation between the fault currents at different detection points and the energy of the first traveling wave head of fault current. The required positions of locators are analyzed according to the relationship between the detected traveling wave and its reflected and refracted waves. The location equation is established by the fault section. PSCAD Simulation experiment indicates that this distributed fault location method has good application value. © 2012 IEEE.


He Z.M.,Shanghai University of Engineering Science | Liu Y.D.,Shanghai JiaoTong University | Shen W.,Shanghai JiaoTong University | Sun X.R.,Liaocheng Electrical Power Company | And 3 more authors.
Applied Mechanics and Materials | Year: 2014

In order to improve the economy of operation of transformer, this study presents a strategy to ensure the safety of power transformer for the situation of overload operation of parallel transformer. According to the variation of actual transformer operation, the authors divide the daily load curve into two typical time periods. In the high load operation period, except the constraint of minimum power loss for the economic operation, the factor for hot-spot temperature rise of the transformer should also be considered, so that an economic operation mode and parallel switching time could be obtained. This strategy estimates the hot spot temperature by the finite difference method, and obtains the optimal switching time through binary searching, according to the environment temperature and load curve. The analysis of the example of the operation of two sets of three winding transformers in parallel with different capacity shows that the method of optimization of the operation could reduce the loss. In the meantime, it could ensure the operation safety of the transformer, and prolong the service life of transformer. © (2014) Trans Tech Publications, Switzerland.


Liu Y.,Shanghai JiaoTong University | Sheng G.,Shanghai JiaoTong University | Hu Y.,Shanghai JiaoTong University | Jiang X.,Shanghai JiaoTong University | And 2 more authors.
IEEE Power and Energy Society General Meeting | Year: 2014

Identification of lightning type can provide directive guidance for the operation and maintenance of transmission lines. In this study, a corresponding relationship satisfied by the polarities of three phases of fault traveling wave current is built under the condition that a fault of transmission line is caused by lightning. On the basis of the lightning overvoltage theory and the boundary condition of transmission line, it is proposed that the back flash should be identified according to the differences and similarities in polarities of three phases of current traveling waves. Based on the modified energy ratio, a method is proposed for the judgment of the transmission line fault caused by lightning and shielding failure, in accordance with the energy variation feature of transient traveling wave. Finally, the identification of types of lightning on the transmission line is achieved. The method is proved to be correct and have good application value by performing simulations and field experiments. © 2014 IEEE.


Wang H.,North China Electrical Power University | Li G.,North China Electrical Power University | Li M.,North China Electrical Power University | Jiang Z.,North China Electrical Power University | And 2 more authors.
Proceedings 2011 International Conference on Mechatronic Science, Electric Engineering and Computer, MEC 2011 | Year: 2011

The lead acid battery, which has been used in electric vehicle since a long time, are now even studied because of the low cost. In this paper some common battery models are recommended, and a third-order dynamic model for lead acid battery is implemented. The identification and validation of the parameters of the proposed lead acid battery model is also mentioned. Finally, the battery model is used in the Fuel cell vehicle (FCV) simulation. The results show that the model can delegate the battery behavior and FCV that includes lead acid batteries has good work performance. © 2011 IEEE.


Zhang F.,Shandong University | Liang J.,Shandong University | Li J.,Liaocheng Electrical Power Corporation | Gao H.,Binzhou Electrical Power Corporation | And 2 more authors.
Dianli Xitong Zidonghua/Automation of Electric Power Systems | Year: 2013

A novel single ended fault location algorithm based on the initial reverse polarity traveling wave (RPTW) detection is proposed. Research shows that the RPTW has less influencing factors, which ensures the high detection reliability, moreover, the time when the RPTW arrives has a certain relationship with fault location, has a piecewise linear characteristic. According to the characteristics of RPTW and combining the initial traveling wave, the fault section and the primary fault location can be determined as soon as the initial RPTW can be identified. After that the exact fault point will be located using other fault information contained in the single ended traveling waves. Only the initial traveling wave and initial PRTW have been used in the present algorithm, which will guarantee the detection accuracy. Simulation results show that the proposed algorithm can effectively locate the fault point, and obviously improve the single ended fault location's reliability and accuracy. © 2013 State Grid Electric Power Research Institute Press.


Liu Y.,Shanghai JiaoTong University | Sheng G.,Shanghai JiaoTong University | Sun Y.,Liaocheng Electrical Power Company | Liang J.,Xian Electrical Engineering Co. | Jiang X.,Shanghai JiaoTong University
Dianwang Jishu/Power System Technology | Year: 2012

On the basis of analyzing characteristic of fault current in overhead transmission line, a method to comprehensively judge the fault zone by utilizing deviation degree among zero-sequence components of the fault current measured at different detecting points and the energy of the first traveling wave of the fault current is proposed. Corresponding relationships among the measured traveling wave of the fault current and its reflected and refracted waves obtained by fault detector installed at different positions are analyzed, and the number of detecting points needed by the distributed fault location system for single-phase ground fault and the installation positions of detectors are put forward. Finally, according to the fault zone corresponding fault location equation is chosen to determine the position of fault point. Simulation results show that by use of the proposed fault location method a more accurate result of fault location can be attained.

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