• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.1
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• pp.47-52
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• 2021

Recently, the share of wind power in energy markets has sharply increased with the active development of renewable energy internationally. In particular, large-scale wind farms are being developed far from the coast to make use of abundant wind resources and to reduce noise pollution. In addition to the electromagnetic interference (EMI) caused by offshore wind farms to coastal or air surveillance radars, it is necessary to investigate the EMI on global maritime distress and safety system (GMDSS) communications between ship and coastal stations. For this purpose, this study investigates whether the transmitted field of MF/HF band from a ship would be subject to interference or attenuation below the threshold at a coastal receiver. First, using geographic information system digital maps and 3D CAD models of wind turbines, the area of interest is electromagnetically modeled with patch models. Although high frequency analysis methods like Physical Optics are appropriate to analyze wide areas compared to its wavelength, the high frequency analysis method is first verified with an accurate low frequency analysis method by simplifying the surrounding area and turbines. As a result, the received wave power is almost the same regardless of whether the wind farms are located between ships and coastal stations. From this result, although wind turbines are large structures, the size is only a few wavelengths, so it does not interfere with the electric field of MF/HF distress communications.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.29 no.1
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• pp.141-146
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• 2005

Recently, the accidents on the sea have arisen due to the increase of the nautical traffic and the digitization of equipments for marine. Therefore, IMO(International Maritime Organization) have provided the recommendation of EMI and EMS for radio communication and equipments of marine from SOLAS cobvention at July 1st 2002. In this paper, we measured EMC environment on the HANBADA, which is Korea Maritime University training ship, for basic EMC environment of a ship. The measuring point was Bridge and Engine Control Room of the ship, we measured the test point that was set at random. Measured Band is from 30 MHz to 2 GHz, polarization measurement is processed both vertical and horizontal polarizaion. We analysed the results in consideration of permissible criteria.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.3 no.2 s.5
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• pp.119-128
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• 2004

Recently, the accidents on the sea have arisen due to the increase of the nautical traffic and the digitization of equipments for marine. Therefore, IMO(International Maritime Organization) have provided the recommendation of EMI and EMS for radio communication and equipments of marine from SOLAS convention at July 1st 2002. In this paper, we measured EMC environment on the Hanbada, which is Korea Maritime University training ship, for basic EMC environment of ship. The measuring point was Bridge and Engine Control Room of the ship, we measured at the test point that was set at random. Measured Band is from 30 MHz to 2 GHz, polarization measurement is processed both vertical and horizontal polarization. We analysed the results in consideration of permissible criteria.

• Korean Journal of Remote Sensing
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• v.15 no.4
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• pp.297-305
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• 1999

Ocean Scanning Multispectral Imager (OSMI) is a payload on the KOMPSAT satellite to perform global ocean color monitoring for the study of biological oceanography. The instrument images the ocean surface using a wisk-broom motion with a swath width of 800km and a ground sample distance (GSD) of < 1km over the entire field of view (FOV). The instrument is designed to have an on-orbit operation duty cycle of 20% over the mission lifetime of 3 years with the functions of programmable gain/offset and on-board image data compression/storage. The instrument also performs sun and dark calibration for on-board instrument calibration. The OSMI instrument is a multi-spectral imager covering the spectral range from 400nm to 900nm using CCD Focal Plane Array (FPA). The ocean colors are monitored using 6 spectral channels that can be selected via ground commands. KOMPSAT satellite with OSMI was integrated and the satellite level environment tests including instrument aliveness/functional test, such as launch environment, on-orbit environment (Thermal/Vacuum) and EMI/EMC test were performed at KARl. Test results met the requirements and the OSMI data were collected and analyzed during each test phase. The instrument is launched on the KOMPSAT satellite on December 21,1999 and is scheduled to start collecting ocean color data in the early 2000 upon completion of on-orbit instrument checkout.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.6
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• pp.1261-1267
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• 2011

Electricity meters using in Korea are about 1.8 million units. From among these, electronic meters for high voltage, about 170 thousand units were installed to the digital type meter and ones for low voltage installed hundreds of thou-sands of meters through a model project. Recently, low voltage meter are expected to complete the installation within several years. Domestic power metering technology is being beyond a simple framework with an electronic type and is rapidly evolving to intelligent smart metering systems in conjunction with promotion of a national smart grid project. Accordingly, it is important to ensure an immunity of meter for electromagnetic field and environmental noise at the installation site. In this paper, we are going to check the validity of international standard that focusing on RF electromagnetic field immunity of meter to secure the quality and improve the reliability in field operation of meter. And we will verify the validity of test specification focused on actual installation environment and are going to offer the improvement plan of test standard.

• Proceedings of the KIPE Conference
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• 2012.11a
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• pp.217-218
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• 2012

A load motor used for warship or submarine is with limited volume and weight, also specific environmental tests like impact, vibration, noise, temperature and EMC/EMI have to be satisfied. Induction motors, synchronous motors, BLDC motor and etc, are used depending on the purpose of using military equipment. Induction Motors are used for a number of military equipment more commonly due to the robust structure and simple maintenance. Domestic and foreign warships have a wide range of voltages as the DC voltage sources with battery are mainly used for them. The ${\Delta}-connection$ operation of the induction motor is required to make the maximum power in a low voltage level. But the elements' temperature of the inverter increases due to high input current when it is in the ${\Delta}-connection$ operation. Therefore, the induction motor must be driven with the Y-connection. The lack of voltage needs to be with the field weakening control. This paper suggests the optimum field weakening control algorithm to drive the induction motor with maximum power in a limited thermal and DC voltage condition.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1326-1327
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• 2008

Recently, the air pollution is supposed is to be the most serious environmental problem. Therefore, a small air cleaner is asked to make comfortable indoor environment for the moderns who have frequent indoor activity. In this study, without generating of the second pollution source, dust in the air and harmful microorganisms can be removed by the electric dust collecting technology which has high reliability and efficiency to be able to remove the impurities even though it is just 0.01${\mu}m$. Accordingly, power sources of the dust collector use, it is not inefficiency and offering to dust collector unstable. In order to overcome the point at issue, a this study, for power factor compensating use the PFC circuit, for removing the noise use EMI filter and for generating the hight voltage use the Cockcroft Walton Circuit. And we study power source on characteristic and improvement.

• Proceedings of the KIEE Conference
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• 2001.10a
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• pp.254-257
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• 2001

This paper is managing about problem and EMI by electromagnetic waves occurrence of electrical appliances and harmfulness of EMS and standard. Specially, because this paper certifies a mouse and electromagnetic waves interception effect of electricity market place which possess electromagnetic waves interception facility, there is effect that contribute in health life that do to secure safe going to sleep condition from electromagnetic waves of electricity market place that is security of computer working environment of safe state through electromagnetic waves interception and essential electric appliance of home life.

• Aerospace Engineering and Technology
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• v.7 no.1
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• pp.142-150
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• 2008

In order to ensure the individual and mutual performances among the telemetry system, tracking system, flight termination system, GPS, and inertial navigation & guidance system which are installed in the KSLV-I 2nd stage and ground equipment of the Naro space center, flight test using a light airplane is required. Since the high degree of test efficiency is fulfilled through the minute plan and analysis about selection of the equipment which are applicable to the test, harness, operation strategy, and antenna installation. KSLV-I communication environment and flight profile should be precisely taken into account during the flight test. In this document, overall aspect of the KSLV-I 2nd stage equipment specification, a rack for the installation, harness, the airplane specification, and flight route which are required for the effective flight test are presented.

• Journal of Sensor Science and Technology
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• v.31 no.6
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• pp.441-447
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• 2022

This study describes a novel method for detecting and measuring partial discharge (PD) on an electrical facility such as an insulated power cable or switchgear using fiber optic sensing technology, and a distributed acoustic sensing (DAS) system. This method has distinct advantages over traditional PD sensing techniques based on an electrical method, including immunity to electromagnetic interference (EMI), long range detection, simultaneous detection for multiple points, and exact location. In this study, we present a DAS system for PD detection with performance evaluation and experimental results in a simulated environment. The results show that the system can be applied to PD detection.