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Tamura Y.,Toshiba Corporation | Takasaki S.,Kyusyu Electrical Power Corporation | Irokawa S.,Toshiba Corporation | Takeda H.,Toshiba Corporation | And 3 more authors.
IEEJ Transactions on Power and Energy | Year: 2011

AC filter design method for SVC and HVDC is commonly known in the relevant CIGRE technical brochure and IEC technical report. However the conventional method requires many iterative calculations of the harmonic voltages and currents until the calculation results become within the regulation levels by changing filter parameters based on the experience. In this respect, a new improved design method is proposed, which enables efficient evaluation on the complex impedance plane to confirm as to whether the proposed filter impedance is in the permissible range. In an actual project of Okuura SVC of Kyusyu Electric Power Co., Inc., the new method was applied to the AC filter design. This paper describes on the actual procedure of the AC filter design with the new method, the actual references of the harmonic performance calculation, and the field test measurement results on Okuura SVC. The calculation results and the filed measurement results are consistent with each other, thus the validity of the new design method is verified on its accuracy and effectiveness. © 2011 The Institute of Electrical Engineers of Japan. Source


Tamura Y.,Toshiba Corporation | Takasaki S.,Kyusyu Electrical Power Corporation | Miyazaki Y.,Toshiba Corporation | Takeda H.,Toshiba Corporation | And 3 more authors.
IEEJ Transactions on Power and Energy | Year: 2011

The voltage variation in the remote system is large when the system is connected by long distance AC cables due to the cable capacitance. In Japan, the longest 54 km 66 kV AC submarine cable interconnection between Kyushyu mainland and Goto-islands was commissioned in 2005. It is requested to mitigate the voltage variation caused by switching off and on of one circuit of AC cables out of two circuits when a fault occurs. Since the conventional voltage control methods such as transformer tap changer or shunt capacitor and reactor banks are not sufficient because of their slow response time, therefore an SVC (Static Var Compensator) was installed in Goto-islands. In such application, SVC control method should be developed not to override the existing voltage control systems. This paper describes the SVC control method developed for Goto-islands AC interconnection project, which can be applied to similar applications. The effectiveness of the control method was verified by effective-value-based simulation results and field test results of which implemented before SVC commissioning in 2007. © 2011 The Institute of Electrical Engineers of Japan. Source


Matsushita Y.,Kyushu University | Mitsuhara N.,Kyushu University | Matsuda S.,Kyusyu Electrical Power Corporation | Harada T.,Kyusyu Electrical Power Corporation | Kumada N.,Kawasaki Heavy Industries
Kagaku Kogaku Ronbunshu | Year: 2012

Fundamental drying behavior of as-mined Loy Yang coal with water content of 56 wt%, a Brown coal from Victoria State, Australia, was investigated. Weight loss due to drying was measured and drying rate was evaluated at a constant temperature of 50-90°C or a constant heating rate of 1-100°C/min. At a constant temperature, the drying rate of Brown coal showed its maximum value in the first period of drying after the heating-up period and decreased gradually. The drying behavior of Brown coal was different from that of wood, one of the bestknown materials in drying, which showed two drying periods, the so-called constant-rate and decreasing-rate drying periods. From the measured data obtained at a constant temperature, the drying rate of Brown coal found to be expressed by the equation proportional to (1-X) with drying fraction X and a proportionality constant, in other words, the drying rate constant was proportional to drying temperature. The validity of the proposed drying rate equation was confirmed by comparing the predicted weight loss obtained by the equation with measured one both at a constant temperature condition and at a constant heating rate. The predicted weight loss due to drying was in good agreement with the measured one in the first and middle drying period after the heating-up period, though that in the final drying period was overestimated. Moreover, the times to achieve various drying fractions were estimated from the measured data and the drying rate equation at constant temperature condition. As a result, the time to achieve a given drying fraction increased with a decrease in drying temperature, and the time to achieve a higher drying fraction drastically increased with a decrease in drying temperature. © 2012 The Society of Chemical Engineers, Japan. Source


Watanabe H.,Kyusyu Electrical Power Corporation | Kusumoto J.,Kyusyu Electrical Power Corporation | Kanaya A.,Kyusyu Electrical Power Corporation | Sato J.,Kyusyu Electrical Power Corporation | And 2 more authors.
Nihon Kikai Gakkai Ronbunshu, B Hen/Transactions of the Japan Society of Mechanical Engineers, Part B | Year: 2011

Fatigue and creep damage of Ni-base superalloys have been investigated using the electron back-scattering diffraction pattern (EBSP) method. The damage caused by high temperature fatigue test is detected as misorientation, and localize at the surface of damaged specimens. The value of misorientation tends to increase with increasing the fatigue damage. Creep damage is also evaluated as the misorientation, but localized around grain boundaries and interfaces of precipitates. The misorientation has a good correlation with the creep strain. Among some misorientation parameters applied in this study, orientation distribution (OD) shows better sensitivity and relativity to the damage than the other misorientation parameters. © 2011 The Japan Society of Mechanical Engineers. Source

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