• Journal of The Korean Society of Agricultural Engineers
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• v.64 no.5
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• pp.9-16
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• 2022

Syngas, also known as synthesis gas, synthetic gas, or producer gas, is a combustible gas mixture generated when organic material (biomass) is heated in a gasifier with a limited airflow at a high temperature and elevated pressure. The present research was aimed at modifying the existing LPG engine generator for fully operated syngas. During this study, the designed gasifier-powered woodchip biomass was used for syngas production to generate power. A 6.0 kW LPG engine generator was modified and tested for operation on syngas. In the experiments, syngas and LPG fuels were tested as test fuels. For syngas production, 3 kg of dry woodchips were fed and burnt into the designed downdraft gasifier. The gasifier was connected to a blower coupled with a slider to help the air supply and control the ignition. The convection cooling system was connected to the syngas flow pipe for cooling the hot produce gas and filtering the impurities. For engine modification, a customized T-shaped flexible air/fuel mixture control device was designed for adjusting the correct stoichiometric air-fuel ratio ranging between 1:1.1 and 1.3 to match the combustion needs of the engine. The composition of produced syngas was analyzed using a gas analyzer and its composition was; 13~15 %, 10.2~13 %, 4.1~4.5 %, and 11.9~14.6 % for CO, H₂, CH₄, and CO₂ respectively with a heating value range of 4.12~5.01 MJ/Nm³. The maximum peak power output generated from syngas and LPG was recorded using a clamp-on power meter and found to be 3,689 watts and 5,001 watts, respectively. The results found from the experiment show that the LPG engine generator operated on syngas can be adopted with a de-ration rate of 73.78 % compared to its regular operating fuel.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.6
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• pp.914-921
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• 2022

The International Maritime Organization (IMO) has set a goal of reducing ship's carbon dioxide emissions by 70% and greenhouse gas emissions by 50% by 2050 compared to 2008. Shipowners and shipyards are promoting various R&D activities such as LNG propulsion, ammonia propulsion, electric propulsion, CO₂ capture, and shaft generators as a way to satisfy this problem. The dual shaft generator has the advantage that it can be directly applied to an existing ship through remodeling. In this paper, the total fuel reduction rate that can be obtained by applying the shaft generator to the existing ship was verified through simulation. For this purpose, the size of the medium-sized ship was defined, and the governor, diesel engine, propeller, torque switch, generator for shaft generator, propulsion motor for shaft generator, and ship model were modeled and simulated.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.2
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• pp.176-187
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• 2016

It takes considerable time to generate accurate clutter signal using conventional clutter generation scheme. In this paper, real-time schemes are proposed, which have reasonable accuracy and are applicable to testing the radar performance. Proposed methods are compared through the simulation, which represented that clutter signal can be generated in real-time when using proposed methods for simulated signal generator.

• KEPCO Journal on Electric Power and Energy
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• v.3 no.2
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• pp.113-117
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• 2017

As the competition in the manufacturing market for small and medium sized generators is intensifying, there is increasing pressure to reduce production cost. Manufacturing the generator stator windings with global vacuum pressure impregnation (GVPI) is a very effective way to reduce costs. However, the stator winding has a fatal disadvantage in that the insulation wears due to vibration in the slot. KEPRI (KEPCO Research Institute) conducted insulation diagnosis for three generators in KOMIPO (Korea Midland Power Co., Ltd.) which were manufactured by GVPI and operated for about 17 years. Insulation diagnosis showed that deterioration of insulation has progressed significantly. Therefore, KEPRI recommended replacing the stator windings of all three generators. In this paper, the insulation properties of the generator stator winding with global GVPI are described by comparing and analyzing the insulation diagnosis results and visual inspection for stator windings.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.11
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• pp.1565-1570
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• 2012

Nuclear power generation is increasing domestic power supply ratio by lower CO2 emission and fuel prices. Currently, nuclear power generator has been operated with maximum power output. Therefore, nuclear power generator could be no effect to managing the reactive power reserve on power system. The reactive power reserve is calculated to the difference between maximum facility and operation generation capacity of the power system. This paper was proposed that load following of nuclear power is control by using 15-bus power system model. In the simulation result, power system is shown to safety state by operating load following of nuclear power generator. This method has be improved the supplied reliability through economic and efficient operation.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.5
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• pp.97-102
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• 2018

In this paper, W-band Waveform Generator for compact radar has been designed and fabricated. DDS (Direct Digital Synthesizer) is applied to generate CW (Continuous Wave) and FMCW (Frequency Modulation Continuous Wave) waveform at high speed. We designed two LO (Local Oscillator) paths for functions of distance delay and distance tracking tests at the prpposed system without extra test equipment. Two mode selections are provided by switch. It is observed that fabricated waveform generator performs -91 dBc/Hz phase noise at offset 1 kHz and -63.2 dBc spurious. Proposed W-band Waveform Generator is expected to apply for W-band compact radar transceiver module.

• Journal of Drive and Control
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• v.12 no.2
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• pp.7-13
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• 2015

In this study, we suggested the wave power generator using horizontal motions of the wave for use in the coastal sea. The length of the horizontal movement of the wave in the vicinity of the sea surface is larger than the length of the vertical reciprocating movement of the wave, hence the proposed device has a wave power transmission plate. In addition, because the motion of the wave is maximum to the sea surface, by arranging the buoyancy tanks at the top of the wave power transmission plate, it is always capable of vertical movement in accordance with the sea surface. To confirm the usefulness of the proposed wave power generator, we constructed a mathematical model of the wave power generator and carried out simulation using bondgraph. Furthermore, the efficiency was verified by measuring the degree of electrical energy production through a preliminary experiment.

• Journal of Applied Reliability
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• v.14 no.3
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• pp.176-181
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• 2014

In these days, new and renewable energy is getting popular around globe and wind power generator is one of the renewable energy. In this study, we conducted a study on defect detection of composite material blade for wind power generator by applying active infrared thermography and produced a defect test piece by applying composite material used for blade of wind power generator. An infrared thermal camera and 2 kW halogen lamp are used for the purpose of research as equipments. Also, we analyzed temperature characteristic by using infrared thermal camera after checking a heat source on a test piece and found effectiveness of infrared thermography to blade of wind power generator by detecting defects resulting from temperature difference of a test piece, which eventually improve the safety and reliability of the composite material blade.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.5
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• pp.601-610
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• 2018

The purpose of this paper is to establish a new optimum Generator Maintenance Scheduling(GMS) considering renewable energy generator. In this paper, the total renewable energy generation is estimated using hourly capacity factor of renewable energy generator. The GMS was optimized with the objective function of maximizing the minimum reserve rate, minimizing the probabilistic production cost, minimizing the loss of load expectation, and minimizing $CO_2$ emissions. In the case study of this paper, GMS considering renewable energy and GMS not considering renewable energy are shown by each objective function. And it shows scenarios of the reliability, the environmental and economical factors when two nuclear power plants inputted and ten coal thermal power plants shut downed respectively.

• Korean Journal of Environmental Agriculture
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• v.42 no.3
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• pp.231-238
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• 2023

We analyzed the variations in the CO₂ concentration and temperature between a CO₂-enriched and control greenhouse. We cultivated Alstroemeria 'Hanhera' in the two greenhouses and assessed the growth parameters (stem length, stem thickness, and the number of flowers) and yield. The CO₂-enriched greenhouse had a CO₂ generator that produced CO₂ at rate of 0.36 kg/h and its windows were programmed to open when the temperature exceeded 20℃ and close when it dropped below 15℃. The control greenhouse had no additional CO₂ supplementation, and its windows were programmed to open when the temperature exceeded 20℃ and close at approximately 17:00. In the morning, CO₂ concentration remained above 500 ppm in the CO₂-enriched greenhouse, which was higher than that in the control greenhouse (approximately 370 ppm). The ventilation effect only through the side windows to reduce the temperature in both greenhouses did not appear dynamically. CO₂ supplementation promoted plant growth, resulting in a significant increase in plant yield of over 60% compared to that of the control greenhouse. Our findings suggest that elevated CO₂ concentration in the morning can significantly promote the growth and development of Alstroemeria during the winter.