A5070662707- Electrical Fault Detection and Protection
- Thermal Analysis in Power Transmission
- High voltage insulation and dielectric phenomena
- Superconducting Materials and Applications
- Power Systems Fault Detection
- Non-Destructive Testing Techniques
- Concrete Corrosion and Durability
- Integrated Circuits and Semiconductor Failure Analysis
- Particle Accelerators and Free-Electron Lasers
- HVDC Systems and Fault Protection
- Solar-Powered Water Purification Methods
- Magneto-Optical Properties and Applications
- Physics of Superconductivity and Magnetism
- Ultrasonics and Acoustic Wave Propagation
- Lightning and Electromagnetic Phenomena
- Dielectric materials and actuators
- Advanced Sensor and Energy Harvesting Materials
- Electromagnetic Launch and Propulsion Technology
- Gold and Silver Nanoparticles Synthesis and Applications
- Seismic Waves and Analysis
- Power System Reliability and Maintenance
- Solar Thermal and Photovoltaic Systems
- Electrostatic Discharge in Electronics
- Conducting polymers and applications
- Electrical Contact Performance and Analysis
Hanbat National University
2024
Lawrence Berkeley National Laboratory
2022-2023
Pukyong National University
2021
Government of the Republic of Korea
2021
Yonsei University
2016-2020
Fault localization is one of the most significant aspects in maintenance high-voltage direct current (HVdc) submarine cables that have unconventional installation characteristics, such as long cable lengths and underwater locations. In order to protect diagnose cable, an improved fault technique, is, time-frequency domain reflectometry (TFDR) tangent distance pattern recognition are proposed this paper. The location information HVdc can be obtained from distance, support results TFDR. To...
The demand for cable diagnostics and monitoring techniques has increased significantly in recent decades. Various diagnostic tests such as partial discharge, dielectric loss, elongation-at-break are available real-world applications. Among the methods, reflectometry can be used to detect location of a fault according reflected signal at impedance-discontinuity point. Because it is nondestructive method applied regardless type, commonly Time-frequency domain reflectometry, an improved type...
For the electrical insulation of a high-temperature superconducting (HTS) cable, wrapped polypropylene laminated paper (PPLP) tape is typically used. Unfortunately, it possible that unexpected faults at layers will be present in cables as result either problematic manufacturing process or an incomplete installation procedure. In order to protect against operational failures grid-connected HTS cable systems, this proposes nondestructive diagnostic technique, i.e., time-frequency domain...
Operation of high-field superconducting magnets relies on diagnostic instrumentation for measuring strain, temperature, and magnetic field variations, detecting quenching, identifying performance problems. Discrete sensor implementation is costly, requires multi-channel data acquisition systems, density often insufficient to resolve problematic locations spatially. Distributed sensing a viable alternative approach providing location-specific information over single terminal output. In...
A high-temperature superconducting (HTS) cable system with the 22.9 kV, 50 MVA, and 410 m length is installed operated at 154 kV Icheon substation of Korea Electric Power Corporation (KEPCO). Unfortunately, it a difficult task to diagnose monitor electrical thermal characteristics HTS in real-time manner. In order protect operational failures grid-connected systems, this paper proposes time-frequency domain reflectometry (TFDR) analysis techniques, i.e., cross correlation instantaneous...
High-temperature superconducting (HTS) cables are expected to be installed in cable tunnels that already constructed urban districts. Therefore, the installation of normal joint boxes is inevitable, and it necessary develop a diagnostic methodology considers both existence joints electrical characteristics HTS cables. In this work, temporal sliding long short-term memory (TS-LSTM) proposed estimate locations can hidden by multiple reflections. TS-LSTM includes long-term for analyzing various...
In this paper, we propose a new time-frequency based analysis method that monitors the state of high temperature superconducting (HTS) cable system in real-time manner and detects current imbalance HTS system. The time-frequency-based utilizes cross Wigner-Ville distribution to analyze localized phase difference reflected signal, which varies depending on insulation characteristics Also, real-world AC 22.9 kV 50 MVA source are used validate performance monitoring order detect phenomenon.
In this paper, new time-frequency-based anomaly detection methodology is proposed for the condition monitoring of high-temperature superconducting (HTS) cable systems. The includes two indices, which are obtained via cross Wigner-Ville distribution and scattering parameter. For validation methodology, applied to an ac 22.9-kV/50-MVA HTS system connected real power grid network. Furthermore, changes in dielectric properties during cooling process current imbalance failure monitored. indices...
When a fault occurs in the high-temperature superconducting (HTS) cable, current consisting of extremely high frequency components is generated and propagated based on transient response HTS cable. Therefore, simulation model characteristic cable essential to obtain accurate results analysis. In this paper, result time domain reflectometry used design To determine parameters, general regression neural network kernel density estimation utilized. After modeling procedure, accuracy evaluated by...
Abstract Solar thermoelectric (TE) generators may potentially provide a viable alternative to photovoltaic devices for producing electrical energy from renewable sources. In this approach, the conversion of solar radiation into heat is essential enhance performance TE devices, which necessitates development efficient light absorbers. Metal nanoparticles (NPs) have gained much attention in regard because they can convert via plasmon‐mediated photothermal effects. study, porous nanocomposites...
A high-temperature superconducting (HTS) cable system requires cooling to maintain a state. If local fault occurs in the HTS cable, current that causes heat can flow. This leads quench, where superconductivity breaks down, inflicting critical damage on system. Conventional reflectometry method detect quench point, but it is difficult distinguish between reflected signals from around joint box and box. In this paper, we propose two steps solve problem. (1) Anomaly detection step: integrating...
The characteristics of the HTS cable including conductivity, permittivity, and insulation vary depending on conditions temperature pressure during operations. We propose a diagnostic method that estimates propagation constant detect location degree fault using stepped frequency waveform reflectometry. performance proposed is verified by experiment regarding estimation detection. results cooled liquid nitrogen are also compared with at room to analyze change according state. expected be...
Quench localization is one of the most important aspects in identifying performance limitations high-temperature superconductor (HTS) devices and applications. In order to localize quench improve spatial resolution, an acoustic-based detection technique using shear-horizontal waves chirplet transform proposed this paper. To verify method, acoustic signals are collected by shear piezoelectric transducers mounted on REBCO tape, heating points localized via time-frequency cross-correlation...
Scattering-mediated photothermal process in the PES/Au membranes enabled local temperature heating inside composite membrane to accelerate kinetics of a model chemical reaction.
High temperature superconducting (HTS) cables are drawing attention as transmission and distribution in future grid, related researches on HTS have been conducted actively. As come to the demonstration stage, failures of cooling systems inducing quench phenomenon become significant. Several diagnosis developed but there still some limitations experimental setup. In this paper, a non-destructive diagnostic technique for detection local change point is proposed. Also, simulation model with...
Instrumentation and control (I&C) cable connected between numerous sensors main room contributes to the safe operation of nuclear power plants (NPPs). Some I&C cables are installed in place exposed degradation causes such as mechanical damage, heat, radiation. In this paper, two aging assessment parameters extracted from results time-frequency domain reflectometry (TFDR) is proposed maintain reliable stable NPPs. To verify method, different EPR insulated distinct manufactures adopted...
Colliders are built on a foundation of superconducting magnet technology that provides strong dipole magnets to maintain the beam orbit and focusing enable extraordinary luminosity required probe physics at energy frontier. The strength plays critical role in dictating reach collider, arguably dominant cost driver for future collider facilities. As community considers opportunities explore new frontiers, importance advanced - both terms performance technology's potential reduction is...
A new quench detection and diagnostic system is required for the reliable operation of high-field superconducting magnets fusion which fabricated with high-temperature superconductor (HTS) cables. The conventional voltage-based methods have a limitation in detecting local temperature changes large-scale HTS magnets. To address limitation, an acoustic-based method using torsional waves applied by piezoelectric transducers proposed. In addition, from sensor data collected transducers,...
High temperature superconducting (HTS) cable operates under relatively low and its unique operating condition brings new challenges in the area of maintenance diagnostics cable. As an example, a difference occurs on connection systems between instruments room HTS cables which eventually leads to thermal energy loss. The loss affects frequency characteristics are critical aspects for simulation systems. In this paper, attempt reduce is introduced with improved connector applying Peltier...
Abstract Impregnation plays a crucial role in the performance and protection of superconducting magnets. To investigate impregnation status during quench training, vector network analyzer (VNA)-based time domain reflectometry (TDR) is introduced. The proposed method analyses focus on demonstrating their applicability within canted-cosine-theta (CCT) magnets, covering both artificially induced quenches using spot heaters naturally occurring quenches. verify method, VNA-based TDR applied to...
Future colliders will operate at increasingly high magnetic fields pushing limits of electromagnetic and mechanical stress on the conductor [1]. Understanding factors affecting superconducting (SC) magnet performance in challenging conditions cryogenic temperatures is only possible with use advanced diagnostics. Diagnostics provide a unique observation window into processes associated operation, give essential feedback to design, simulations material research activities. Development novel...
Fault localization is one of the most significant aspects in maintenance high-voltage direct current (HVDC) submarine cables that have unconventional installation characteristics such as long cable lengths and underwater locations. In order to protect diagnose cable, an improved fault technique, i.e., time-frequency domain reflectometry (TFDR) tangent distance pattern recognition are proposed this paper. The location information HVDC can be obtained from distance, support results TFDR. To...