Advanced Materials Research Vol. 905

Abstract: This paper presents a hierarchical hybrid mapping model for environment representation for the estimation of vehicle pose and environment feature. The environment map converted from the point cloud data gotten by LIDAR is represented with a cylindrical logarithmic polar grid, which considerably improves the efficiency and accuracy of environmental feature detection. To lower the search scope of data association and reduce the dimension of state estimation, we adopt a topology map in the top level. The autonomous ground vehicle experimental results shows that the proposed method has better performance.

Abstract: Development of environment-friendly building materials has recently been increasing with the use of industrial waste and by-products, but concrete containing blast furnace slag (BFS) is excellent in terms of environmental load and shows relatively insufficient early strength. Development of by-products to supplement this insufficiency is deemed necessary. Therefore in this study, an early strength activator blast furnace slag (A-BFS) was developed and environment performance of the developed A-BFS was assessed to assess environmental load (CO₂). As a result, early strength was developed in mortar specimen mixed with A-BFS. When environmental load (CO₂) was assessed on the mortar specimen, life cycle CO₂ emission from production of 1kg of A-BFS was found to be 0.057kg-CO₂/kg.

Abstract: In relation to global warming, there is a need for development of alternative material to reduce cement use by concrete. Accordingly in this study, A-BFS (Activator Blast Furnace Slag) mixed with an activator composed of industrial wastes such as wastewater sludge and sewage sludge was developed. Physical property for compressive strength development was tested on concrete mixed with the developed A-BFS. In addition, environmental load (CO₂) emission and reduction performance were analyzed on concrete mixed with A-BFS.

Abstract: A LCL filter is an effective device to suppress high level frequency components which are generated by PWM converter. However, the use of the LCL filter can cause the stability problems of the system. This paper presents two control methods of the LCL filter in an isolated battery-converter-wind turbine system by considering positions of control currents, the converter side currents and the grid side currents. In addition, the effect of the unit power factor control of the system is also mentioned in this paper. The simulation results show out the effectiveness of control methods.

Abstract: DSTATCOM is used for recompense of reactive power and disturb caused by different loads in distribution system.To develop a DSTATCOM with battery energy source system and control of energy flow among the system components. Multilevel inverter is used in DSTATCOM for mitigating voltage sag at the load side. Hybrid multilevel inverter with fuzzy logic and minimised switches is presented. Voltage sags are generated by faults in the distribution feeder, with the three-phase 7-level hybrid multi level inverter for mitigating the voltage disturbances. Seven level hybrid inverter which is used for low energy PV source and high power grid connected applications by applying VMC converter. DCDC converters based on the tri-state switching unit and voltage multiplier cells. VMC converter having ability to maintain current and voltage of input source and it gets maximum level for grid applications. Improving the efficiency, by harmonic reduction in the power system and fast load compensation achieved by the combination of voltage multiplier cells and seven level multilevel inverter circuits with fuzzy control techniques. Then, computer simulation by means of the program Matlab/Simulink preliminarily verifies the usefulness of the proposed device.

Abstract: This paper presents a novel, control parameter independent evolutionary search technique known as Seeker Optimization Algorithm (SOA) for the design of a eighth order Infinite Impulse Response (IIR) Band Pass (BP) filter. A new fitness function has also been adopted in this paper to improve the stop band attenuation to a great extent. The performance of the SOA based IIR BP filter design has proven to be much superior as compared to those obtained by real coded genetic algorithm (RGA) and standard particle swarm optimization (PSO) in terms of highest sharpness at cut-off, smallest pass band ripple, highest stop band attenuation, smallest stop band ripple and also the fastest convergence speed with assured stability recognized by the pole-zero analysis of the designed optimized IIR filter.

Abstract: This paper proposes a installation of a static synchronous compensator (Statcom) used battery energy storage system (BESS) for compensting the reactive power of the micro-grid in Gapa island. At present, the micro-grid in Gapa island has two squirrel cage induction generator (SCIG), and it consums a lot of the reactive power. To reduce the capacity of the Statcom, a SCIG is replaced by a permanent magnet synchronous generator (PMSG). The simulation will be carried out in two cases: (i) real system with two SCIGs; (ii) modified system with one SCIG, one PMSG and the Statcom. With the statcom, the reactive power is compensated and the grid voltage is stable. The simulation results will valuate the effectiveness of the proposed control method.

Abstract: As the development of wind generation, traditional methods for determining reserve capacity are no longer appropriate. In order to determine the optimal spinning reserve for system with wind generation, this paper set the reserve capacity based on the reliability index which includes the system reliability and wind generation uncertainties. The model is then calculated by the Lagrangian Relaxation method. According to the result, the method for determining reserve capacity proposed by this paper is applicable.

Abstract: Modular multilevel Converter (MMC) is a new type of voltage source converter (VSC) topology. The use of this converter in a high-voltage direct current (HVDC) system is called by a MMC-HVDC system. The MMC-HVDC has the advantage in terms of scalability, performance, and efficiency over two-and three-level VSC-HVDC. In this paper, the MMC-HVDC system is used to connect between main grid in Jeju Island and virtual offshore wind farms. The aim is to transfer the power from offshore wind farm to the main grid and to compensate reactive power for the main grid. The simulation is carried out by using PSCAD/EMTDC program, and the results will confirm the effectiveness of the proposed control method.

Abstract: SF₆ has been widely used in the power industry as an arc quenching and insulation medium due to its excellent physical and chemical properties since 1960. However, experience shows that SF₆ gas medium has many disadvantages under certain conditions: gas may encounter liquefaction when installed in cold areas; SF₆ is still expensive; dielectric strength is sensitive to electric field, and require higher equipment design and manufacturing processes; SF₆ is a greenhouse gas, and is used under limitations since the Kyoto Protocol was signed in 1997^[. Unfortunately, its difficult to find no environment hazards and to replace SF₆ completely at present. In view that the greenhouse impact of SF₆ is still very little (it is estimated less than 0.01%) in the atmosphere recently and it does not damage the ozone layer, it becomes a focus to find gas mixtures containing SF₆ to replace pure SF₆ gas to reduce the emissions and environmental impact of SF₆. Scientists from all countries and international major GIS manufacturers, electric power sector are working together to develop new gas mixture of SF₆-insulated electrical equipment ^[2].