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.

진공차단기 스위칭 써지 특성 해석 및 저감 방안

김종겸(Jong-Gyeum Kim) 대한전기학회 2013 전기학회논문지 Vol.62 No.2

Vacuum circuit breaker(VCB) has been widely used for interruption of load current and fault current for high voltage motor in the industrial field. Its arc extinguishing capability is excellent compared to other breakers. But it has the potential to cause multi reignition surge by high extinguishing capability. Surge voltage is generated by the opening and closing of VCB. Multi reignition surge of VCB is steep-fronted waveform. It may have a detrimental effect on the motor winding insulation. So, most of users install a protection device to limit steep-front waveform at the motor terminal or breaker side. So, most of users install a protection device at the motor terminal or breaker side. This protective device is surge absorber(SA) such as ZnO and RC type. In this study, we analyzed whether there is any effect when two type SA is applied to the VCB multi reignition surge. We confirmed that ZnO SA is slightly more effective than RC SA for reduction of multi reignition surge.

저압 콘덴서의 열원 분포 해석

김종겸(Jong-Gyeum Kim),이동주(Dong-Ju Lee),김일중(Il-Jung Kim),박영진(Young-Jeen Park) 대한전기학회 2010 전기학회논문지 Vol.59 No.7

In this study, the heat source distributions at the end side and the center of the electrode are analyzed to estimate the electrical stress due to the harmonics from the nonlinear loads. The governing equation at the analysis area of low voltage condenser are numerically solved using the finite element software package to analyze the effects of heat source distribution due to the 5th and 7th harmonics, which can exist normally in the distribution network and can be applied to the low voltage condenser. Finally, the heat source distribution from the harmonics is compared and analyzed with the heat source distribution from the fundamental component of the applied voltage

리액터 탭 절환에 의한 유도전동기의 기동 특성

김종겸(Jong-Gyeum Kim) 대한전기학회 2014 전기학회논문지 P Vol.63 No.1

An induction motor is most widely used to obtain driving force in the industrial field. The induction motor is generated a high current at starting. A starting current is often more than five times of rated current. A high starting current can cause problems such as voltage drop in the power system. In order to solve these problems, a reactor starting method has been widely applied in a large motor capacity. There are differences in the operating characteristics of induction motor corresponding the switching time of reactor tap. In this study, I analyzed that current, torque, power of induction motor are different from changing time and tap setting values of reactor tap.

진공차단기 다중 재발호시의 서지 특성 해석

김종겸(Jong-Gyeum Kim),박영진(Young-Jeen Park) 한국조명·전기설비학회 2018 조명·전기설비학회논문지 Vol.32 No.4

Vacuum circuit breakers are widely used as power switches for high voltage motors. This breaker generates a high switching surge voltage at the time of opening under lower power factor conditions such as start-up or no-load. When the breakdown voltage of the vacuum interrupter is lower than the transient recovery voltage, high frequency current flows and multiple reignition phenomena occur. Especially, the steep-fronted surge voltage which occurs in multiple re-ignition can act as electrical stress to the motor winding. Therefore, it is necessary to identify the causes and measures to reduce the electric stress. In this paper, we analyzed the effect of steep surge voltage and its reduction method when multiple reignition and high frequency quenching current occurred under the condition that the high voltage induction motor is shut off immediately.

전압 및 전류 고조파에 의한 커패시터 동작 특성

김종겸(Jong-Gyeum Kim),박영진(Young-Jeen Park),이동주(Dong-Ju Lee),이은웅(Eun-Woong Lee) 대한전기학회 2009 전기학회논문지 P Vol.58 No.3

Capacitor is basically used for the power-factor compensation and sometimes as the passive filter to reduce harmonics of nonlinear load. Since the impedance of capacitor is inversely proportional to the frequency. The harmonic current may result in the problems of voltage distortion and resonance. Capacitor has easily fall under by two harmonic components, a nonlinear load and a distorted utility voltage. The amplified harmonic current and voltage may damage power capacitor. Hence the pre-investigation of harmonic is needed before designing and application the power factor for reducing fault rate. In this paper, we analyzed that voltage and current with harmonics components act on the capacitor under the resonance condition. we concluded that both voltage and current harmonics have an bad effect on the capacitor and current harmonics is a bitter rather than effect by voltage harmonics.

고조파 필터용 커패시터와 리액터의 특성 해석

김종겸(Jong-Gyeum Kim),박영진(Young-Jeen Park),이은웅(Eun-Woong Lee) 대한전기학회 2009 전기학회논문지 P Vol.58 No.1

Recently, application of non-linear load is gradually increased. Non-linear load produces harmonic components of current during the energy conversion transition. Passive filter is used for reducing of harmonics in the user power systems. This filter, which is composed of capacitor and reactor, frequently get out of order by electrical stress. There are voltage and current increase when capacitor and reactor are applied in the user's filter systems. If increased voltage and current is above stipulated values, they have severely an influences on the life of capacitor and reactor. This paper describes that the voltage and current of capacitor used for filter is within the limits of allowable values, but reactor is beyond the limits and reveals spike voltage. Therefore this phenomenon brings about premature fault of reactor and capacitor.

전력용 커패시터의 전기적 스트레스 해석

金宗謙(Jong-Gyeum Kim),朴永鎭(Young-Jeen Park),李殷雄(Eun-Woong Lee),李東周(Dong-Ju Lee) 대한전기학회 2008 전기학회논문지 P Vol.57 No.4

Power capacitors is widely used for power factor correction and component of passive filter in the user power systems. Recently, application of non-linear load is gradually increased. Non-linear load produces harmonic components of current. There are series resonance and parallel resonance when capacitors are applied in the user electrical application. If this harmonic component matches resonance, voltage and current is magnified and has severely an influences on capacitor. This paper purposes a new method for the magnitude of voltage and current by the frequency scan analysis without equivalent circuit for the actual circuit at the resonance condition.

고압 유도전동기 역률 보상설비의 특성 해석

金宗謙(Jong-Gyeum Kim),朴永鎭(Young-Jeen Park),李殷雄(Eun-Woong Lee) 대한전기학회 2008 전기학회논문지 P Vol.57 No.3

Reactor starring method has the advantage of simplicity and closed transition in spite of lower starting torque per kVA. This method allows a smooth start with almost no observable disturbance on transition and is suitable for applications such as centrifugal pumps or fans. Reactive power doesn't contribute to work but needs to sustain the electromagnetic field required for the induction motor to operate. Starting power factor of induction motor is specially lower than running power factor. Power factor application is needed to compensate for the lower power factor of induction motor. This power factor compensation systems is occasionally being hit by the effects of the starting reactor connection position at the starring. stopping of high-voltage induction motor. This paper describes voltage and current stress affected by the installation position of power factor compensation application at the reactor starting method.

오차의 허용범위를 고려한 수동형 필터의 특성 해석

김종겸(Jong-Gyeum Kim),김일중(Il-Jung Kim) 대한전기학회 2009 전기학회논문지 P Vol.58 No.1

Reactors are connected with capacitors to passive filter circuits for reducing harmonics caused by power conversion application. This passive filter frequently gets out of order by voltage and current stress. Especially filter reactor has too much voltage harmonics components, its trouble rate is higher than capacitor. In this paper, we analyzed voltage and current of reactor and capacitor used for passive filter by simulation and measurement. H reactor has a tolerance on variation of reactance value, series resonance frequency is different from originally filter design frequency and parallel resonance can be generated at the close point of the former. Because filter absorbs harmonic component of non-linear load, much of harmonic voltage has been impacted on reactor.