Power flow congestion relief by using customer‐side energy storage systems

In recent years, energy storage systems have increasingly been expected as a means of load leveling of the annual load factor. Of course there is an effect of installing the energy storage systems at the substation. But some customers operate their storage system in an integrated way and it also has an effect of increasing the load factor. In this paper the authors proposed that the energy storage systems on the customer side be used for congestion relief on transmission networks. However, it is not clear which kind of customer has the effect of relieving transmission line congestion. First, this paper assumes the authors determine the optimal configuration of energy equipment including energy storage systems. We propose a new contract whereby electric utility subsidizes a part of the entrance cost of the energy storage systems and customers change the output pattern of energy storage according to the request of the electric utility. This paper evaluates the possibility that the contract gives merit to both the electric utility and the customer. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 158(1): 36–45, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20299     

Simulation of Lag Phenomena and Pulsed I-V Curves of Compound Semiconductor FETs as Affected by Impact Ionization

Turn-on characteristics of GaAs MESFETs are simulated when the gate and the drain voltages are changed abruptly, and quasi-pulsed I-V curves are derived from them. It is discussed how the slow current transients (lag phenomena) and the pulsed I-V curves are affected by the existence of substrate traps and surface states. It is also discussed how the characteristics are influenced by impact ionization of carriers.     

Wafer bonding technology for silicon-on-lnsulator applications: A review

School of Engineering, Duke University, Durham, North Carolina, 27706. The status of wafer bonding technology especially for silicon-on-insulator (SOI) materials is reviewed. General advantages of wafer bonding as well as specific problems of wafer bonding, such as interface bubble formation, and solutions for these problems are discussed. The specific requirements for SOI materials in terms of SOI layer thickness and the appropriate thinning procedures are dealt with. Interface properties such as bonding strength and electrical properties are also reviewed. Various device results are mentioned.     

Rapid Reconstitution of Biosynthetic Machinery for Fungal Metabolites in Aspergillus oryzae: Total Biosynthesis of Aflatrem

Reconstitution of the biosynthetic machinery for fungal secondary metabolites in Aspergillus oryzae provides an opportunity both for stepwise determination of the biosynthetic pathways and the total biosynthesis of fungal natural products. However, to maximize the utility of the reconstitution system, a simple and rapid strategy for the introduction of heterologous genes into A. oryzae is required. In this study, we demonstrated an effective method for introducing multiple genes involved in the biosynthesis of fungal metabolites by using the expression vectors pUARA2 and pUSA2, each of which contains two cloning sites. The successful introduction of all the aflatrem biosynthetic genes (seven genes in total) after two rounds of transformation enabled the total biosynthesis of aflatrem. This rapid reconstitution strategy will facilitate the functional analysis of the biosynthetic machinery of fungal metabolites.     

Tensile fatigue behaviour of ultra-high performance fibre reinforced concrete (UHPFRC)

The tensile fatigue behaviour of ultra-high performance fibre reinforced concrete (UHPFRC) under constant amplitude fatigue cycles is presented. Three series of uniaxial tensile fatigue tests up to a maximum of 10 million cycles were conducted with the objective to determine the endurance limit of UHPFRC that was supposed to exist for this material. The fatigue tests reveal that an endurance limit exists in all three domains of UHPFRC tensile behaviour at S-ratios ranging from 0.70 to 0.45 with S being the ratio of the maximum fatigue stress to the elastic limit strength of UHPFRC. Rather large variation in local specimen deformations indicates significant stress and deformation redistribution capacity of the UHPFRC bulk material enhancing the fatigue behaviour. The fatigue fracture surface of UHPFRC shows features of the fatigue fracture surfaces of steel, i.e. fatigue crack propagation is identified by a smooth surface while final fracture leads to rather rough surface. Various fatigue damaging mechanisms due to fretting and grinding as well as tribocorrosion are identified.     

Development of water pipe cooling system for power cables intunnels

A full-size test line was constructed to study the water pipe cooling system for a bulk-power transmission line installed in a tunnel. Based on the test data and their analysis, a technique for designing the system has been established. The results have indicated an effective layout of the cooling pipes in the tunnel, and have validated the accuracy of the computer models to determine thermal characteristics of the tunnel system. An efficient control method to operate the cooling system according to the load changes of the cables was developed. The chosen layout is shown to be more effective than the dispersed layout because it accelerates the air convection and makes the air temperature more uniform. Furthermore, the thermal convection resistance between the tunnel wall and the air is reduced. It was also verified that the air temperature distribution along the vertical shaft could be predicted by thermal convection analysis. This cooling system is scheduled to be applied to a 154 kV power cable line in 1990