Advanced Materials Research Vol. 748

Abstract: Ferromagnetic resonance overvoltage is an internal overvoltage and it often occurred in the power distribution system which neutral point ungrounded. A 35kV power system is used as the prototype to establish the 35 kV substation's simulation model which is based on the ATP - EMTP and ferromagnetic resonance overvoltage is researched and analyzed In this paper. The ferromagnetic resonance overvoltage which is stimulated by single-phase ground fault is studied in this paper studied and ferromagnetic resonance suppression methods were also studied. The results show that the nonlinear resistor is connected in the PT primary neutral side and small resistance is connected in the PT open delta are effectively methods which can restrain ferromagnetic resonance overvoltage.

Abstract: Islanding detection is a very essential function for a photovoltaic grid-connected system. Islanding phenomenons not only damage to equipment, but also endanger to the safety of the maintenance personnel. Passive islanding detection methods that use alone have considerable non-detection zone (NDZ); active islanding detection methods that use alone are that join disturbance to system, but the disturbance will cause system instability [1]. In this paper, an over/under voltage and over/under frequency detection method combines with an improved active power perturbation detection method are proposed. The photovoltaic system can be reduced non-detection zone (NDZ) with improved the power quality and reduced the total harmonic distortion (THD) through this method.

Abstract: As the numbers and running distance of Chinese high-speed trains increase, many electric multiple units (EMU) gradually enter into overhaul stage, EMU maintenance bases face challenges of transition from practical exploration, regular production to lean production. In accordance of business requirement, built a model of dynamic resource allocation, task splitting, and soft precedence constraints. By the design of nonlinear decline inertia weight factor, a refined particle swarm optimization (PSO), as well as the corresponding parallel transformation scheme from particle to schedule, is presented. Finally, computational analysis is performed to validate the model and algorithm on optimization capabilities, resource utilization and performance.

Abstract: With the development of society, the energy as the restriction of human society's development is tension increasingly, solar energy as one kind of green non-pollution energy is developed and used gradually. The combination of solar energy water heating system and buildings become more and more closely, however, the power consumption of the pump as the main energy consumption of a solar energy water heating system, the setting of the pump circulating temperature influent the power consumption of the whole system directly. This paper mainly analyze the content above. In order to give some useful advice on the design and operate of the solar energy water heating system in the future.

Abstract: As the technology of intelligent substation is developed gradually, the significance of he Ethernet switch in the substation is obvious increasingly.Firstly, the learning and transmitting principle of Ethernet frame are introduced, then the network program of secondary system using the switch in the hierarchial structure is described. And then a detailed analysis of the VLAN, QoS, mirror and ring network is given, also the various technical application scheme are provided according to a variety of IED features and data flow characteristics. On the basis of the different business needs and different message types, the reasonable design of network topology and the flexible use of these switching technology , can support security, stability, reliable transmission of communication message in intelligent substation , therefore the whole substation becomes more strong.

Abstract: A novel hybrid clamped dual-PWM three-level converter topology is proposed for induction motor drives in this paper. The switching states of hybrid clamp three-level converters increase to sixty-four from twenty-seven switching states of diode clamp three-level converters. In order to realize optimization of its redundant voltage space vectors by detecting voltage of clamp capacitor and difference of capacitor voltage in DC side, Generating an optimized switching pattern, The hybrid clamped three-level converter increases the voltage levels number, reducing the harmonics associated to the commutation frequency and limiting the dv/dt by all the switches . It can quickly balance the DC voltage, Realized system of 4-Quardant Running. the control circuit and main circuit was designed with DSP and CPLD, experimentation results proved it is very effective and practicability.

Abstract: The distributed generation (DG) may lead to a great impact on the reactive power flow, feeder voltage profile and the means of voltage regulation when integrated into a typical distribution system. Therefore, there is possibility that the customers voltage violate the permissible limits. In order to regulate the voltage of the distribution system with DG, local voltage and reactive power control (VQC) based on fuzzy control theory is adopted in substation and the Static Var Compensator (SVC) is installed in the appropriate node in this paper, and the fuzzy controller of VQC has been designed at the same time. A simplified model of a real 10kV radial distribution system has been simulated in MATLAB to illustrate the use of the voltage regulation method, and the simulation results show that the proposed method can regulate the line voltage of distribution system with DG within the regulated voltage ranges.

Abstract: The green design of products is highly beneficial in the alleviation of environment burdens. During the product lifecycle, energy-consumption is one of the main roots of environmental pollution. Therefore, energy optimization for green design is an important path to reduce the environmental pollution. Sequentially, the concept of the energy design factor was presented, which was applied in the energy-optimizing design of the mechanical product in the use stage. Based on the analysis of function in the use age of products, the energy consumption information of products was extracted. During the use stage of products, the energy-consuming model was established. Then the energy design factors was extracted and applied to the energy optimization design of products. Finally, the model and method in the paper were validated by a case of motorcycle’s clutch.

Abstract: This paper through patent map fuzzy cluster analysis system and method, researches development status in the fields of wind power, and the patent technology focus areas and its own characteristics , putting an emphasis analysis on patent technology of wind power around the world , we summarize and generalize technology development trends , and the future technology identified methods of the patents focus areas are discussed. Finally, we put forward a idea which comes from technology identification to prediction and evaluation.

Abstract: This paper presents a mathematical model to simultaneously optimize the cost of electricity and the satisfaction of a residential consumer using the communication infrastructure of a smart grid. For this task the concept of Pareto optimality has been used. It is possible to consider the satisfaction of the consumer as an independent objective to be maximized, and simultaneously, to minimize the cost of the electrical bill. In future works a multiobjective evolutionary algorithm will be applied along with the mathematical model presented in this paper.