• The Transactions of the Korean Institute of Power Electronics
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• v.12 no.5
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• pp.424-431
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• 2007

This thesis proposed H-Bridge Multi-Level Inverter for Fluidized Bed Combustion Boiler Secondary Air Fan in 200MW thermal power plant. The adjustable speed drive systems improve the efficiency in lightly load condition and extend the life span of motor by limiting the over current at starting. H-Bridge Multi-level Inverter is composed of the several series low voltage power cell inverters, which have the independent isolated do link, in each phase. KEPRI(Korea Electric Power Research Institute) has successfully completed to develop, install, and commission H-Bridge Multi-level Inverter(6.6kV, 1MVA). This thesis gives a full detail about H-Bridge Multi-level Inverter, proposed boiler DCS(Distributed Control System) logic, and commissioning test result.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1808-1811
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• 2005

The prediction of AOV(air-operated valve) performance is normally evaluated by the allowable opening thrust margin for the opening and closing stroke. However, it is not easy to carry out the dynamic test measurement for all the valves in the nuclear power plant due to the safety and operating conditions. The analysis of the available and required thrust for the valve is simulated as an alternate method to turn around this obstacle. The required air pressures to the stem displacement are discussed for differential valve pressure obtained by experiment. The result of the simulation is compared with that of the experiment. SIMULINK in MATLAB was used for the simulation and the results show good agreement with the actual test carried out with Fisher globe valve.

• Journal of Power System Engineering
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• v.15 no.1
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• pp.11-17
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• 2011

본 연구는 라디칼 착화(Radical Ignition이하 RI) 기술을 적용한 부실직분식 CNG(Compressed Natural Gas) 엔진의 구동특성에 관한 것이다. 실험엔진은 단기통 디젤엔진을 개조하여 사용하였으며, 이는 부실식 디젤엔진처럼 연소실이 주실과 부실로 나누어져 있다. 부실에 분사된 CNG는 스파크플러그로 점화하며, 부실로 부터의 연소가스가 주실 희박 혼합기를 시켜 구동하는 엔진이다. RI 기술은 연소속도를 향상시킬 수 있다. 본 연구는 주로 저부하 RI-CNG 엔진의 성능을 연구하였다. 연료분사기간은 9 ms, 공기과잉률은 1.0, 1.2, 1.4로 하였다. 연료분사시기는 엔진의 배가밸브가 닫히는 ATDC $20^{\circ}CA$ 부터 $120^{\circ}CA$ 사이로, $20^{\circ}CA$ 간격으로 지각시켜 가며 실험하였다. 본 연구는 연료분사시기 및 공기과잉률이 연소최고압력 ($P_{max}$), 연소최고압력시기(${\Theta}_{pmax}$), 도시평균유효압력(IMEP), 사이클 변동계수($COV_{imep}$), 연소속도에 미치는 양향 등을 구하고 분석하였다.

• Journal of Internet of Things and Convergence
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• v.3 no.1
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• pp.25-31
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• 2017

In the future a future type new city and the latest apartment will be built, and the IoT technology will be constructed and combined in large numbers indoors of ordinary households. An air cleaner that makes people in it comfortable is built in, and the suction port that sucks in the air of the air purifier and the discharge port that discharges it are set up around the room and come out. However, this is impossible to adjust because there is only a central switch on / off. Also, consuming a lot of electricity so that many electricity charges are caused by huge electricity consumption will eventually be a waste of resources. This would like to be adjusted and driven through the fine dust detection device to the room built-in air purifier and that has provided a solution to save electricity. In addition, since it exists in and around the room, you can grasp the position of the person and connect to the home network to enhance the convenience. Also, through analysis of the air, we provide a health-check solution that checks the user's health and adjusts it appropriately.

• Particle and aerosol research
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• v.16 no.3
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• pp.65-72
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• 2020

In this study, the indoor fine dust concentration in an office of the Korea Knowledge Industry Center was measured for about 80 hours when the concentration of atmospheric PM_2.5 was very high. The effect of the operation of the air cleaner and the forced ventilation system on the indoor PM_2.5 was investigated, and the particle size distribution of the indoor and outdoor particles was analyzed. When forced ventilator and air purifiers were partially used, the indoor PM_2.5 concentrations were maintained between 27.7 ㎍/㎥ and 32.9 ㎍/㎥ when the atmospheric PM_2.5 was 127.7 ㎍/㎥ to 141.6 ㎍/㎥ during working hours. It is more effective to operate the air purifier without operating the forced ventilation system when the concentration of the PM_2.5 is high since the PM_2.5 penetrating the installed filter is continuously introduced indoor from the outside.

• Proceedings of the KIEE Conference
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• 2006.10d
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• pp.185-187
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• 2006

본 논문에서는 평택화력 제2호기 FDF(Forced Draft Fan : 압입송풍기, 이하 FDF) 출구의 공기량제어를 Vane Control 시스템으로 구성되어 있는 것을 구동 유도전동기에 가변속 제어시스템(이하 VFD: Variable Frequency Drive)으로 교체하여 발생한 실험결과를 보여준다. VFD는 Vane을 전개(全開)하고 전동기 속도를 변경시켜 연소에 필요한 노내 공기량을 제어하는 방식이다. VFD 운전은 정속도 Vane 개도 운전에 비해 Throttle Loss를 최소화해서 에너지 절감효과는 크지만 간단한 Vane 제어기에 비해 복잡한 전력전자제어시스템이 어우러진 기기로 신뢰도는 떨어지는 것이 사실이다. 따라서 고도의 신뢰성이 요구되는 전력생산 보일러에서 후비보호책으로 VFD 고장 시에 Vane제어 모드로 절환은 필연적으로 필요한 설비이다. VFD에서 Vane으로 절환 시에 일어나는 과도상태를 최소화하기 위해서는 보일러 연소제어 알고리즘의 최적화가 필요하다. 본 논문에서는 구현된 제어알고리즘을 정리한 것이다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.04a
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• pp.994-999
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• 2008

The necessity of diagnosis of the rotating machinery which is widely used in the industry is increasing. Because vibration diagnosis can avoid sudden breakdown of machine and reduce the maintenance costs. In the factory, Air-Compressor which can affect the performance and capacity of output is important machine. Therefore, in this paper, The measuring and analyzing is carried out for air-compressor in order to the factor of resonance and resonance avoidance for air-compressor. The result of diagnosis and solution is discussed in this paper.

• Proceedings of the KIPE Conference
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• 2007.07a
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• pp.259-261
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• 2007

논문은 동해화력발전처의 이차공기송풍기를 가변 회전수 제어하여 소내 소비 전력을 절감하고 전동기의 직입기동에 의한 스트레스를 줄이기 위하여 실증 적용된 동해화력발전처 이차 공기 송풍기 구동용 H-브릿지 멀티레벨 인버터에 관한 것이다. H-브릿지 멀티레벨 인버터는 독립적으로 절연된 직류 부를 갖는 저압의 단상 인버터(셀 인버터)를 다수 직렬 접속하여 고압 3상 전압을 출력하는 Cascaded H-브릿지 전압형 인버터이다. 본 논문에서는 동해화력발전처에 실증 적용된 6.6kV, 1MVA급 인버터의 계통 병입 후 부하 변동 시험을 통하여 신뢰성을 입증하였다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1766-1769
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• 2005

Air-operated valve(AOV) is one of principal valves that are using to control fluid flow in nuclear power plants. AOV is suffered from damage and malfunction by the abrasion, corrosion and vibration of valve parts under the long time operation. This mechanical trouble and malfunction of valve is critical for the safety of power plant. So a periodic diagnosis for safety of power plants is inevitable to guarantee the safety of the power plant. But depending on the type of the actuator and valve body, various types of AOV exist. In this study, It is developed the diagnostic system that users of power plants are easy to handle in this paper.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.1022-1025
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• 2003

Although the globe is the most typical valve to control high pressure drop in piping system, it is very hard to figure out the characteristics of flow field in the globe valve caused by its complex geometry. So there is very few studies to find out flow characteristics of globe valve. In this study, numerical analysis for flow field in the globe valve is carried out using the Fluent code which is commercial CFD program. Pressure drop through the globe valve is also measured to verify the results come from numerical analysis. Comparing experiment with numerical analysis, two results are very close to each other. Also finite element method is employed to evaluate the safety of globe valve using the results coming from the flow analysis to make the boundary conditions for FEM analysis. Maximum stress appears on the inlet channel of valve where inlet flow runs against. Because the maximum stress between 11.7 MPa to 3.6 MPa is within 3.4% of yield stress. the structural safety of valve is considered to be very sound