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3상 4선식에시 비선형 부하의 운전시 유도전동기의 특성 해석
김종겸,박영진,이은웅,Kim, Jong-Gyeum,Park, Young-Jeen,Lee, Eun-Woong 한국조명전기설비학회 2006 조명·전기설비학회논문지 Vol.20 No.8
3상 4선식 전원공급 시스템에서 단상 및 3상 부하의 운전하에서 전압 불평형은 부하의 불평형 운전에 의해 발생되고, 전류 불평형은 떨어진 전압 품질에 의해 더욱 심해진다. 에너지 변환장치로 사용되는 여러 형태의 컨버터는 3상 4선식 배전시스템에 직접적으로 고조파 전류를 주입함으로서 고조파 왜란을 증가시킨다. 고조파 전류는 전동기 출력 토크를 감소시키고, 전동기를 과열 또는 소음을 증가시키며 회전자에 토크 맥동을 증가하여 기계적인 공진과 진동을 발생하는 등 여러 가지 부작용을 낳고 있다. 따라서 본 논문은 3상 4선식 배전시스템에서 선형 및 비선형 부하의 혼합 운전시 불평형과 고조파 성분에 의해 유도전동기의 특성 변화에 대한 연구로서 선형 단독운전, 비선형 부하 결합에 따른 특성 변화를 해석한 것으로서 단상 비선형 부하의 추가 운전시 5 고조파 필터로도 저감이 어려운 고조파로 인해 토크 맥동 횟수는 줄고 리플값은 증가함을 확인할 수 있었다. Voltage unbalance will be generated by the load unbalance operation such as combination operation of single & three phase load and current unbalance will be more severe by the deteriorated voltage quality. Under the these unbalance conditions, all power electronic converters used in different types of electronic systems can increase harmonic disturbances by injecting harmonic currents directly into the feeder grid of three phase 4-wire. Harmonic current may cause torque to decrease. it may also overheat or become noisy and torque oscillation in the rotor can lead to mechanical resonance and vibration. This paper presents a scheme on the characteristics of induction motor under the combination of linear & non-linear loads at the three phase 4-wire power distribution system by the unbalance and harmonic components. It was able to confirm that the number of torque pulsation decreased and torque ripple values increased by the harmonics that reduction was difficult by five harmonics filters at additional driving time of single-phase non-linear load.
김종겸(Jong-Gyeum Kim),류연수(Yeon-Su Ryoo) 대한전기학회 2015 전기학회논문지 Vol.64 No.5
Recently, many advanced countries are devoted to the development of eco-friendly new-renewable energy to prepare for the depletion of resources. Korea belongs to the absolute lack of energy to import from abroad 97% of energy use. So, development and supply of eco-friendly energy such as small hydro power has been required even more. Our country has a large number of small-sized reservoirs and dams. So, hydro generator has been installed at the small reservoirs and dams with the economy. Since the discharge flow of agricultural reservoir is not constant, the guide vane of wicket gate is used for adjusting the output of the generator. In this study, we have confirmed that the guide vane control of water turbine under the conditions of flow variation will improve the output and efficiency of induction generator.
김종겸(Jong-Gyeum Kim),박영진(Young-Jin Park),이은웅(Eun-Woong Lee) 한국조명·전기설비학회 2004 한국조명·전기설비학회 학술대회논문집 Vol.2004 No.5월
Most of LV customer has been composed the 3-phase for wire system distribution system which is supply simultaneously at the 1-phase & 3-phase load. In this system, the composition of the power apparatus system is simple rather than conventional separation mode of the 1-phase & 3-phase. But due to uneven load unbalance or unclean power quality, various kinds such as de-rating or power losses become an issue. In this paper, we measured and analyzed voltage and current waveform in the field, compared with internationally allowable voltage unbalance limits.
유도전동기 효율향상에 따른 역률 보상 콘덴서 최적 선정에 대한 연구
김종겸(Jong-Gyeum Kim) 대한전기학회 2016 전기학회논문지 Vol.65 No.7
Induction motor requires a rotating magnetic field for rotation. Current required to generate the rotating magnetic field is immediately magnetizing current. This magnetizing current is associated with the reactive power. Induction motor is always required reactive power. If reactive power is supplied only to the power supply side, the power factor is low. Therefore, it is to compensate the power factor by connecting capacitors in parallel to the motor terminal. If the capacitor current is greater than the magnetizing current of the motor, there is a possibility that the self-excitation occurs. High voltage generated by the self-excitation leads to insulation failure on the motor. So it is necessary to calculate the power factor correction capacitor capacity the most suitable to the extent that the magnetizing current does not exceed the capacitor current. In this study, we first computed the magnetization current and the reactive power of the induction motor and then calculates a limit of the maximum power factor by comparing the magnetizing current and the capacitor current installed in order to achieve the target power factor.