Applied Mechanics and Materials Vols. 799-800

Abstract: Drag analysis is vital to measure the performance of the autonomous underwater vehicle (AUV) as well as the AUV thruster. Most of the previous drag studies is regarding to the shape and swimming method that contribute to the AUV performance. However, few attention was given on drag which influence the development of thruster. Hence, this research was conducted to analyze the drag of the micro AUV in a laminar fluid flow in order to find the optimum thrust that must be gained by a contractile water jet thruster (CWJT). Besides, these studies also focus on the dynamic pressure and skin friction that forms the total drag which acted on the AUV surface. Drag was measured by using pull technique and simulation technique for AUV speed below 0.5ms^-1. The results show that the recorded drag was between 9.0 x 10^-4N and 1.8 x 10^-1N. The trend line between the simulation data and experimental data has no significant difference and thus it shows that the simulation data were verified. Both results exhibits that the drag increase tremendously regarding to the AUV speed increment.

Abstract: In order to solve the problem of free surface processing of tool redundancy,the tool lack problem, and the demerit of low machining efficiency, etc., based on the iso-scallop method, based on the iso-scallop method, we put forward a kind of free surface NC machining tool path optimization algorithm,make the surface boundary discrete point set, which is generated by point set ring machining path, diagonal connection and then use the path of the adjacent curve, forming cutting tool machining line.finally, the calculation of step size and line spacing in machining path based on the iso-scallop method and the process of feeding direction is optimized. Proved by the simulation process, the algorithm is feasible and can effectively avoid tool redundancy and tool lack problems,concesquently, processing efficiency improved significantly.

Abstract: This paper is devoted to the study of distributed generation units impact on pricing on the wholesale power energy market. The paper deals with results the analysis of the wholesale electricity market and power. This analysis is necessary for proper impact assessment of distributed generation units on a total optimization. Optimization calculations performed for the real power system, when distributed generation units operating the basic and peak modes, as well as the cost-effectiveness of this modes.

Abstract: This paper is devoted to four-phase electrical grids of high and extra-high voltage, principles of its formation and its possible operation and maintenance in united power system of Russia. Development of new simulation model of four-phase power grid for further realization in software is under consideration. Special attention is given to compliance with present both technical and economical requirements of this model in Russian Federation. Economic analysis of four-phase power system applying is done by means of comparison of different kinds of transmission Ural – Siberia.

Abstract: This paper presents an application of an asynchronous back to back VSC-HVDC system. Which uses multilevel converter a 7-level Diode-Clamped SPWM converters topology technique for the realization of HVDC system, rated 300MVA (±300 kV). The controller has been proposed by using PQ control and feed-forward decoupled current control algorithm. The design and experimentally controllers of VSC in lab scaled test, MATLAB/Simulink program were performed VSC-HVDC transmission system, the simulation in order to evaluate transient performance, can be controlled independently under two phase to ground faulted and three phase to ground faulted conditions. The system are used as a guideline for analysing and design of the data process control with the PQ-control HVDC system.

Abstract: A design and simulation for microstrip line filter with semicircle defected ground structure has been researched. In this paper, simulated soft (Ansoft HFSS V.6.0) used to be simulated the frequency response under different parameters such as dimensions, amounts of SDGS.The results show good performance of SDGS in high cut-off frequency, erase of harmonic frequency, smaller dimension. Final, a filter with4.4GHz center frequency,high Q-factor had been design and fabricated.

Abstract: This research focuses on evaluating and analyzing the behavior of smart grid power distribution system with multiple, interconnected distributed generations (DGs). This topic is especially relevant to Thailand, which employs a radial distribution topology and has insufficient use of energy storage system (ESS). Integration of DGs with distribution power systems is a necessity to achieve reliable and efficient performance. The characteristics of each category of DGs must be studied to improve the power system. The main task of the interconnected system is to control and maintain voltage of the power system in an acceptable range for high reliability, efficiency and quality. The proposed study consists of two critical objectives. Firstly, we will investigate the principle operation of DGs that uses renewable energy sources interconnected with the smart grid. The second and final goal is to evaluate and analyze the impact of DGs on the power distribution system. Power injection from DGs can reduce total power loss and improve system performance. In addition, the presence of DGs can increase the voltage level and robustness of the system more than traditional electrical network. However, high penetration of DGs may have an effect on voltage changes at the bus.

Abstract: Service restoration in a distribution power system aims at finding a series of switching operations - a restoration plan, that restores power given an occurrence of a fault, considering multiple objectives and constraints. In this research, we first elaborate that many of common objectives and constraints depend on plan’s physical properties that can be obtained efficiently by simulating the plan, using simulation software like DIgSILENT PowerFactory. However other objectives/constraints cannot be computed by physical simulation because they depend on non-physical and/or non-functional properties not intrinsic to the plan, such as the power company's policies and the market information. From this observation, we propose a framework for distribution service power restoration integrating multiple knowledge sources: heuristics representing the expertise of experienced operators are used to construct possible plans, DIgSILENT PowerFactory computes plan’s physical properties, while non-physical properties are provided by relevant knowledge bases. To demonstrate the appropriateness of the framework, we developed a proof-of-concept implementation.

Abstract: With the gradual expansion of China's electrical network construction, network scale and transmission capacity, a reasonable electrical network construction scale research is urgent for the optimized power system development. In this paper, a blackout risk assessment index system as well as the risk calculation model under different electrical network scales is established, followed by a series of blackout risk value calculation of constitutive units in an IEEE-14 node standard system under typical patterns, hence the validity of the model is verified via comparison with the actual blackout risk value of the system. The result indicates that that the ranking of blackout risk values under different connection patterns with the same amount of lines is polygon, quadrilateral and triangle.

Abstract: In order to reflect the influences of the stochastic uncertain of wind power on the optimal decision-making of the power system spinning reserve, a probabilistic optimization model of the spinning reserve is proposed. Considering uncertain factors such as predicted-deviation of wind, predicted-deviation of load and fault outage of generator, the capacity outage probability table is combined with predicted-deviation of wind and predicted-deviation of load. By introducing the analytic expressed probability reserve constraints into the unit commitment model considering the wind power, the spinning reserve of power system can be optimized to the expectable contingency level. Using a calculation example, the effectiveness of the model is proved, providing a new model for uncertainty analysis and optimal scheduling decisions of power system containing wind.