Applied Mechanics and Materials Vols. 494-495

Abstract: Focusing on the non-linear, time-varying, strong coupling and external load disturbance existing in PMLSM, a fuzzy PID controller based on genetic algorithms is designed to control the speed of PMLSM by absorbing the advantages of PID control and fuzzy control, and the genetic algorithm method is used to optimize fuzzy control rules. A simulation experiment was made to compare the effects of traditional PID control and fuzzy PID based on genetic algorithm control by Matlab. The simulation results verify that fuzzy PID control based on genetic algorithm is superior to PID control in dynamic stability performance and speed tracking power.

Abstract: Against the existing poor dynamic performance, difficult to adjusting parameters of the controllers issue in PMSMs vector control system, based on the PMSM's dq rotating coordinate model, an inverse system model of PMSM is deduced. And a pseudo linear system realizing the decoupling of the d-axis current and mechanical velocity is constructed. By synthesizing the pseudo linear system, a sliding mode variable structure controller is proposed. In order to estimate rotor's position and speed, a reduced order observer for back electromotive force is proposed. At last some simulations are proceeded to verify the proposed system's performance. The simulation results show that the control strategy mentioned in this paper has good dynamics, steady state performance. Rotors position and speed can be accurately estimated by the proposed method.

Abstract: Recently, it becomes the head of concern for the Micro-grid to derive an optimal operational planning with regard to energy costs minimization, pollutant emissions reduction and better utilization of renewable energy sources (RESs), which accompanied by a Wind Turbine/Fuel Cell/Photovoltaic and Battery hybrid power source to level the power mismatch or to store the surplus of energy when its needed. In this paper, a new method based on multi-objective Modified Honey Bee Mating Optimization (MHBMO) algorithm is proposed and implemented to dispatch the generations in a typical micro-grid considering economy and emission as competitive objectives. The problem is formulated as a nonlinear constraint multi-objective optimization problem to minimize the total operating cost and the net emission simultaneously. The proposed algorithm is tested on a typical MG and its superior performance is compared to those from other evolutionary algorithms such as GA (Genetic Algorithm) and the original Honey Bee Mating Optimization (HBMO).

Abstract: To effectively predict cascading failure in power system, a cascading failure prediction method in power system based on multi-agent and hybrid genetic algorithm is constructed. A cascading failure prediction procedure in power system was established by multi-agent and hybrid genetic algorithm to investigate the emergent behaviors of cascading failures and to further study the prediction and defense of cascading failures. Finally, the cascading failure prediction simulation system of power system based on this method was demonstrated and validated by Flexsim software. The result showed that the proposed method was available, and can provided guidance for avoiding and predict cascading failure in power system, and support for stable performance in power system.

Abstract: Retracted article: Based on the reliability theory of power communication network, reliability analytic methods arc proposed for Ethernet passive optical network (EPON) protection networking of the power distribution communication access layer. By using the system availability theory, the reliability and cost of EPON protection networking arc quantitatively analyzed for the access layer of four kinds of power distribution communication network, i. c., tree-type network of single power supply redundancy protection, hand-in-hand network of whole chain protection, dual-power dual-T network of full link protection, and ring-type protection network. The optimal networking solutions arc discussed and summed up for the EPON protection networking schemes of power distribution communication network in current operation.

Abstract: An energy optimizing operation model of BCHP distributed energy supply system is proposed in this paper. The objective function and its constraint conditions are determined so as to minimize the total cost. Not only the cooperation between BCHP and electric air conditioner, but also the influence of spot price of electricity is considered in this model. According to the demand forecast of cooling, heating and power load, operation schemes of some different typical days of BCHP system are optimized. Improved particle swarm optimization algorithm is adopted to solve the energy optimizing operation model for BCHP. Taken an actual commercial building as an example, this paper makes a comparison between BCHP system and separate supply system under the condition that electricity micro turbine generated is allowed to be sold to utility.

Abstract: Fast Cut Back condition is one of the most severe dynamic transient operation conditions for coal-fired power units. Here has carried out the study on the main parameters correlation analysis and system modeling of No. 2 unit from HaiFang thermal power plant. The prediction results show the model built here is reasonable and feasible. Besides, from the process of correlation analysis, it is obvious that Pearson correlation coefficient could be used for compression of information features in order to reduce the dimension of the model.

Abstract: Weather, industrial structure and power demand side management can affect the load, however, the power demand side management has the most direct influence on the change of load. This paper first introduces the purpose of the electric power demand side management, then it introduces the relationship between the load forecasting and the power demand side management, furthermore it respectively introduces a variety of load forecasting method according to the time distribution, finally it compares the advantages and disadvantages of load forecasting methods for each time distribution respectively, and this will provide a new basis for power grid planning.

Abstract: Western resource-based city (WRC) develops rapidly under the develop-the-west and energy resource development strategy. Both of the economy growth and the resource exploitation will make greater demands on the science of power network planning. Therefore, urban power network planning will face more specific risks. Based on fuzzy membership theory, this paper studies the risk identification of WRC power network planning, and summarizes the key risks. Finally, we identify the risks from aspects of policy, economy, environment and load systematically, establish an evaluation index system of specific risks of WRC power network planning, and provide fundamental decisions for risk aversion of WRC power network.

Abstract: Along with the construction of the strong smart grid, many intelligent terminal equipments and wireless communication devices are widely applied to the smart grid, bringing convenience to the construction of the smart grid business systems as well as some serious security issues of confidentiality. The data transmitted through the wireless channel by various types of wireless power terminals in the wireless network communication is vulnerable to eavesdropping and other attacks. In this paper, we proposed an security access architecture and authentication protocol of power terminal based on the theory of the trusted network connection (TNC) and gave the specific authentication protocol process based on the practical application in the smart grid environment. Eventually, we confirmed that the design of the scheme can ensure the integrity and security of the terminal itself according to the safety analysis, so as to build the trusted computing environment of electric power communication network system, ensuring the safety of the whole smart grid application environment.