Applied Mechanics and Materials Vols. 325-326

Abstract: The common-mode current along the harness is one of the main reasons which can not meet the automotive electromagnetic compatibility (EMC) standards for equipment or system. So, the harness model is the critical factors for the automotive EMC prediction. In this paper, the harness network equivalent model is proposed, which is based on the terminal loads and the equivalent wave impedance. The equivalent model is also demonstrated from the simulation results by finite element method.

Abstract: The focus of this paper centers on the analysis of the close coil current signal in circuit breakers (CBs). The characteristic behavior of the close coil is analyzed by the electromagnet control law and a mathematical model is made to describe the dynamic characteristics of the close coil. Results of simulation and experiment are presented in the form of curves of the current of the close coil. The results show that the accuracy of the steady-state and dynamic-state model is satisfactory.

Abstract: The increase in the number of electronic and electric systems used in the automotive industry necessitates a high level of electric power. To respond to this high electric power demand, it will be necessary to increase the voltage of the batteries and the current and to use new power connectors. A connector provides a separable interface between two subsystems of an electronic system. The main function of the connector is to transmit a signal or distribute power. For power connectors, heating can lead to an increase in contact resistance and sometimes even to contact surface melting and thus to connector damage. In this study, vibration tests and heat evolution of a commercial power connector used in the automotive industry was undertaken. The connector includes two spring lamellas on each side and the pin is flat. The pin is introduced between the two lamella springs and is submitted to vibration tests. Using an experimental set-up, the mechanical insertion force, the temperature and the resistance evolution can be measured. To quantify these parameters at the contact zone, a numerical modeling, using the finite element software Ansys, is used to give the change of the insertion force during several insertion-extraction cycles and to solve the differential equations for heat transfer in a transitory mode.

Abstract: For the complexity of the distribution network and the particularity of single-phase grounding fault, intelligent distribution network grounding fault line selection model based on the Extreme Learning Machine (ELM) information integration is proposed in the paper. When a single-phase grounding fault happened, the relation functions for the wavelet packet decomposition, the fifth harmonic method and the traveling wave method are respectively determined, the fault estimate data of transient zero-sequence current are calculated. The fault line is accurately judged by the ELM networks information fusion. Through analyzing MATLAB simulation result about different ground fault line selection, the validity and accuracy of the method are verified.

Abstract: This paper proposes an improved strategy for on-line rolling generation dispatch. Based on the framework of Lagrange dual relaxation, the problem is transformed and decomposed into primal-problem and N subproblems multipliers and system constrains are satisfied iteratively. The sub-problems are solved by an efficient dynamic programming algorithm without changing the condition of convergence of the framework. Numerical results indicate that the proposed method is fast and efficient in dealing with numerous system constrains.

Abstract: The traditional automatic switchover device installed in substation only uses local real-time information to make control strategies, with the logic of device predetermined, so it could not adapt to different operating modes. A new wide-area automatic switchover system based on energy manage system (EMS) is proposed in the paper. The wide-area automatic switchover modeling is established through automated modeling and the real-time rest oration control is implemented. The system solves the power supply restore under serial single power supply failure. By comprehensive use of information of the whole network, the automatic switchover can coordinate with other automatic security devices and protections. In addition, the control strategies and network security will be checked and modified in order to prevent from overload and improve security of automatic switchover strategies. The system has been used in Guangdong power grid of China.

Abstract: The cancellation of time-of-use tariff setting policy from State Development and Reform Commission made certain impacts on the extension of storage power saving technology. The advantages and disadvantages of storage power saving technology for involved participants are analyzed. It is concluded that storage power saving technology is not on favorable moment for promotion, however, it still worth to be promoted. The conflict of electricity coal market pricing with state-fixed electricity price should be fundamentally solved by government and the compensation for existing storage power users needs extra works. Furthermore, in order to remove the obstacles in storage power saving technology promotion, it is urgent to improve the energy consumption efficiency of energy storage apparatus.

Abstract: Ultra high voltage (UHV) AC transmission is a trend in the modern transmission technology development, the UHV substation is the center in the power system. The lightning invasion waves pose a serious threat to the safety of the substation, therefore it is very important to improve the features of the substation anti-lightning. The arresters of UHV substation bus sides, the role of restraining the lighting invasion waves on main transformer have been researched. Applying ATP-EMTP, a simulation model of the lightning over-voltage invasion substation along the double-circuit self-reliance transmission line was built. Whether and how the number of arresters influences the lightning waves were analyzed comparatively. The maximum amplitude of the lightning current can be reduced when the arresters installed in the bus side, and the protective effect of the transformer can be improved effectively.

Abstract: sland operation is a special operation mode for service restoration for the smart distribution system with distributed generation. In this paper, a model of island reconfiguration of the smart distribution system is proposed. The objection of this model is maximizing the total power supply profit. Meanwhile, load priority, controllable and uncontrollable load, and the restrictions of power balance, voltage and equipment capability are all taken into account. The island configuration problem is first simplified as a special knapsack problem, and based on the solution of this knapsack problem an initial island scheme is gained. By feasibility checking and adjusting, a island configuration is finally proposed. The results of the samples demonstrate that the model and method presented in this paper is feasible and valid.

Abstract: The transmission line is an important part of the power system, its reliability will directly affect the reliability of the power system. The reliability of the overhead line plays a crucial role for the power system reliability. This paper analyze the reasons of the falling of the overhead lines, establish a fault tree, and make qualitative and quantitative analysis of the fault tree.