• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1608-1609
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• 2011

In this study, in order to develop the evaluation method for XLPE materials for HVDC cables, DC/Impulse superposition testing system was builded up. Throughout the P-spice simulation, optimal values of the protection resistor for the DC generation system and the blocking capacitor for the Impulse generator were calculated. DC/Impulse superposition system showed good result maintaining their proper wave shapes and amplitudes. This system would be planned to apply to the evaluation of XLPE materials for HVDC cables.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2003.10a
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• pp.81-86
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• 2003

This paper deals with the performance analysis and design of impulse turbine for OWC type wave energy plant. Numerical analysis was performed using a commercially-available software FLUENT. This parametric study includes the variation of several important parameters such as the number and shape of blades, hub ratio and tip clearance. Since parametric study at various flow coefficients requires considerable amount of computing tim, two-dimensional analysis was employed to find out optimum principal particulars in rather simple manner. Full three-dimensional calculation was also performed for several test cases to confirm the validity of two-dimensional approach. Up to the present stage, tentative result is well demonstrating the usefulness of 2-D analysis.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1416_1417
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• 2009

This paper shows the characteristic of wave tail according to inductance values in 10/$350{\mu}s$ impulse circuit with crowbar switch. The PSpice was used to simulate the 10/$350{\mu}s$ current waveform and lightning current impulse generator was used to generate real current waveform. As a capacitor of condenser bank increases, a virtual front time increases and a time to half-value decreases. To get a perfect 10/$350{\mu}s$ current waveform, we should consider the combination of circuit values of the inductance, capacitance, time difference between trigger pulses and charged voltage of capacitor bank.

• Proceedings of the KSME Conference
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• 2002.08a
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• pp.549-552
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• 2002

The objective of this study is to clarify the detailed performances of the impulse type radial turbine and to present an optimum configuration of the turbine. The impulse type radial turbine has been manufactured and investigated experimentally under steady and sinusoidally oscillating flow conditions by model testing. Then, the starting characteristics under sinusoidally flow conditions have been evaluated by a numerical simulation using a quasi-steady analysis. As a result, the running and starting characteristics of the impulse type radial turbine for wave energy conversion have been clarified. Furthermore, the recommended configuration is presented, especially for setting angles of inner and outer guide vanes.

• Journal of Ocean Engineering and Technology
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• v.19 no.6 s.67
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• pp.1-7
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• 2005

This paper deals with the design and aerodynamic analysis of a special-type impulse turbine, with an end plate for wave energy conversion. Numerical analysis was performed using a CFD code, FLUENT. The main idea of the proposed end plate was to minimize the adverse effect of tip clearance of turbine blade, and was borrowed from ducted propeller, with so-called penetrating end plate for special purpose marine vehicles. Results show that efficiency increases up to $5\%$, depending on the flow coefficient; a higher flow coefficient yields increased efficiency. Decrease of input coefficient CAwith an end plate is the main reason for higher efficiency. Performance of end plate at various design parameters, as well as flow conditions, was investigated; the advantages and disadvantages of the presentimpulse turbine were also discussed.

• Journal of Ocean Engineering and Technology
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• v.18 no.5
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• pp.1-6
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• 2004

This paper deals with the performance analysis and design of impulse turbine for owe type wave energy plant. Numerical analysis is performed using a commercial software FLUENT. This parametric study includes the variation of several important parameters, such as the number and shape of blades, hub ratio, and tip clearance. Since parametric study at various flow coefficients requires a considerable amount of computing time, two-dimensional analysis is employed to find out optimum principal particulars. Full three-dimensional calculations are also performed for several test cases, in order to confirm the validity of the two-dimensional approach. Up to the present stage, tentative results are demonstrated the usefulness of 2-D analysis.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2001.05a
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• pp.21-27
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• 2001

This paper describes numerical analysis of the impulse turbine with fixed guide vanes, a high performance bi-directional air turbine having simple structure for wave energy conversion. The numerical analysis of the 2-dimensional incompressible viscous flow based on the full Reynold-averaged Navier-Stokes equations which was made to investigate the internal flow behavior. Numerical results are compared with experimental data obtained by T.Setoguchi laboratory. As a result, as suitable choice of design factor has been clarified with the understanding of the internal flow from the numerical analysis.

• Journal of Ocean Engineering and Technology
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• v.18 no.6 s.61
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• pp.1-7
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• 2004

This paper deals with the performance analysis of the impulse turbine for a owe type wave energy conversion device. Numerical analysis was performed using the commercially-available software FLUENT. This parametric study includes variation of the setting angle of the guide vane. Since parametric study at various flow coefficients requires a tremendous amount of computing time, two-dimensional cascade flow approximation was employed to determine the optimum principal particulars in a rather simple manner. A Full three-dimensional calculation was also performed for several cases to confirm the validity of the two-dimensional approach. Results were compared to other experimental data, such as Setoguchi et al. (2001)'s extensive set of data, and found that the usefulness of 2-D analysis was well demonstrated. The advantages of each method were also evaluated.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.28 no.3
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• pp.91-96
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• 2014

Modern electronic circuits are becoming more vulnerable to damage by surges, and it is required to improve the impulse withstand voltage performance of electrical and electronic equipment. This paper presents the impulse withstand voltage performance of lighting equipment connected to power lines, and the impulse withstand voltage tests for fluorescent lamp, LED lamp and halogen lamp were carried out according to the reference standards under normal service conditions. To conduct performance tests against lightning surge, a combination wave ($1.2/50{\mu}s$ voltage - $8/20{\mu}s$ current) was employed. The test surge was applied between lines or between line and ground of the specimen to be measured. The test surge was applied synchronized at the peak value of the positive and negative AC voltage waves. As a consequence, some specimens satisfied the impulse withstand voltage test criteria, but lighting equipment such as 36W fluorescent lamps, 5W and 5.5W LED lamps and 50W halogen lamp were damaged at the test voltage levels between power lines. It is needed to improve the qualities of lighting equipment to satisfy EMC immunity requirements of equipment for general lighting purposes.

• Journal of Ocean Engineering and Technology
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• v.20 no.1 s.68
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• pp.20-25
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• 2006

This paper deals with the design and aerodynamic analysis of a so-called 'ring-type' impulse turbine for wave energy conversion. Numerical analysis was performed using the CFD cock, FLUENT. The main idea of the proposed turbine rotor was to minimize the adverse effect of tip clearance of the turbine blade; the design was borrowed from a ducted propeller with connected ring tip for special purpose marine vehicles. Results show that the efficiency increases up to $10\%$, depending on flaw coefficient, with the higher flaw coefficient yielding better efficiency. Decrease of input coefficient CA was the main reason for higher efficiency. Performance of ring-type rotor at various design parameters, as well as flaw conditions, was investigated, and the advantages and the disadvantages of the present impulse turbine were also discussed.