• Nuclear Engineering and Technology
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• v.52 no.10
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• pp.2262-2273
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• 2020

Digital twin technology can provide significant value for the prognostics and health management (PHM) of critical plant components by improving insight into system design and operating conditions. Digital twinning of systems can be utilized for anomaly detection, diagnosis and the estimation of the system's remaining useful life in order to optimize operations and maintenance processes in a nuclear plant. In this regard, a conceptual framework for the application of digital twin technology for the prognosis of Control Element Drive Mechanism (CEDM), and a data-driven approach to anomaly detection using coil current profile are presented in this study. Health management of plant components can capitalize on the data and signals that are already recorded as part of the monitored parameters of the plant's instrumentation and control systems. This work is focused on the development of machine learning algorithm and workflow for the analysis of the CEDM using the recorded coil current data. The workflow involves features extraction from the coil-current profile and consequently performing both clustering and classification algorithms. This approach provides an opportunity for health monitoring in support of condition-based predictive maintenance optimization and in the development of the CEDM digital twin model for improved plant safety and availability.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.05a
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• pp.210-213
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• 2002

For insulation design of the superconducting transformer, many types of insulation tests should be carried out. To clarify the components of insulation for superconducting transformer, there are main four parts as 1ike that turn-to-turn interior of each primary and secondary windings, layer-to-layer between primary and secondary windings, and winding to grounded structures. The insulation components should meet the required withstand voltage of the system and enough safety factors must included. As the fundamental insulation characteristics, we tested surface flashover voltage of spacer that would place between the coils and would take the role of both cooling duct and insulator. The structure of spacer in practice vary depending on coil type, in this work we considered double pancake coil for the superconducting transformer. In this study we tested flashover voltages of several arrangement of spacer.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.05b
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• pp.61-64
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• 2004

Recently, the RF inductive discharge or inductively coupled plasma (ICP) continues to attract growing attention as an effective plasma source in many industrial applications, the best known of which are plasma processing and lighting technology. To the point of lighting sources, the electrodeless fluorescent lamps utilizing an inductively coupled plasma (ICP) have been objects of interest and research during the last decades, mainly because of their potential for extremely long life, high lamp efficacies, rapid power switching response. The electrodeless fluorescent lamp that is dealt with in this work comprises a bulb filled with rare gas and amalgam of vaporizable metal and has a coil provided with a winding around the ferrite. Current through a coil produces a magnetic field in the discharge space. The changing magnetic flux then produces an azimuthal electric field E around the coil, according to Faraday's laws of magnetic induction.

• Proceedings of the KIEE Conference
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• 2004.11a
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• pp.285-288
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• 2004

Recently, the RF inductive discharge or inductively coupled plasma(ICP) continues to attract growing attention as an effective plasma source in many industrial applications, the best known of which are plasma processing and lighting technology. To the point of lighting sources, the electrodeless fluorescent lamps utilizing an inductively coupled plasma(ICP) have been objects of interest and research during the last decades, mainly because of their potential for extremely long life, high lamp efficacies, rapid power switching response. The electrodeless fluorescent lamp that is dealt with in this work comprises a bulb filled with rare gas and amalgam of vaporizable metal and has a coil provided with a winding around the ferrite. Current through a coil produces a magnetic field in the discharge space The changing magnetic flux then produces an azimuthal electric field E around the coil, according to Faraday's laws of magnetic induction.

• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.6
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• pp.155-165
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• 1998

The resistance coefficient and heat transfer performance are studied for the turbulent water flow in a smooth coiled tube having variable curvature ratios and a corrugated-coiled tube having a ratio of coil to tube diameter of 22. Experiments are carried out for the fully developed turbulent flow of water in tube coils on the uniform wall temperature condition. This work is limited to tube coils of R/a between 22 and 60 and Reynolds numbers from 13000 to 53000. The tube having a ratio of coil to tube diameter of 27 among the 3 smooth tube coils shows the best heat transfer performance. A corrugated-coiled tube(R/a=60) shows more excellent performance than a smooth coiled tub (R/a=60) at a similar curvature ratio. The friction factor f is sensitive to changes in the velocity profile caused by a temperature gradient. Allowance was made for the pressure loss in the short inlet and outlet lengths and due to the presence of the thermocouple inlet and outlet as a result of separate experimental on a straight tube. It is to be expected that the allowance at the exit will be somewhat too low because of secondary flow effects carried over from the coil.

• Progress in Superconductivity and Cryogenics
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• v.24 no.4
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• pp.50-54
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• 2022

High temperature superconducting (HTS) magnets for large-capacity energy storage system need to be composed of toroid magnets with high energy density, low leakage magnetic fields, and easy installation. To realize such a large capacity of a toroid HTS magnet, an HTS cable with large current capacity would be preferred because of the limited DC link voltage and instantaneous high power required for compensation of the disturbance in the power grid. In this paper, the optimal operating strategies of the SMES for peak load reduction of the microgrid system were calculated according to the load variation characteristics, and the effect of compensation of the frequency change in microgrid with a SMES were also simulated. Based on the result of the simulation, key design parameters of SMES coil were presented for two cases to define the specification of the HTS cable with large current capacities for winding of HTS toroid coils, which will be need for development of the HTS cable as a future work.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.11B no.3
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• pp.81-85
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• 2001

Processes for optimizing the coil shape of deflection yoke are proposed A very accurate and practical winding modeler is developed and volume integral equation method (VIEM) is used for field calculation. Two steps of optimizations are done by using (1+1) evolution strategy. Those are dimensional optimization and pin-position optimization Various techniques are applied for reducing computational time for the optimization.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2004.04a
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• pp.504-507
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• 2004

Previous studies on the liquid Gallium ion sources used an electro-chemically etched tungsten wire with a coil-type heater. Such a structure requires excessive power consumption in the course of heating the liquid metal. In this work, a new structure is proposed that replaces the coil-type heater. It uses a Gallium reservoir made of six pre-etched 250 $\mu\textrm{m}$ tungsten wires that surround the needle electrode. Gallium loading at the reservoir is observed to be much more stable, resulting in an improved beam stability.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.12
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• pp.129-135
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• 1996

This paper presents the effectiveness of the dynamic vibration absorber consisting of a single mass, coil springs and oil damper on the resonance freauency ratio and amplitude ratio for damped linear systems, that is, primary vibration system with damping. The effects of the dynamic vibration absorber are investigated numerically and experimentally for values of mass ratio, natural frequency ratio, and damping ratio. The experimental results show good agreement with calculated ones. As a result, the characteristics shown by the present work are useful in optimal tuning the dynamic vibration absorber in practice.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.05a
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• pp.421-426
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• 2003

Micro-suing that used on micro mechanism should be equal to distance between pitch and correct of shape. Therefore, micro spring must make by super-precision working. But, current step of super-precision processing depends on special quality of work piece and is ineffective the aspect of cost and productivity yet. Also, to use as demandable length shearing process perform but even if make precision spring, in the aspect of quality of coil spring make difficult that produce product of good quality. Therefore, purpose of this study presented proposed process that extract the point of processing factor after perform finite element analysis applying existing sheet shearing process to suing shearing process consider cost and productivity after evaluate.