• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2000년도 추계종합학술대회
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• pp.669-672
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• 2000

This paper presents the methodology which analyze the effect of harmonics in power system. Considering the effect of less-harmonics, economic life and system loss, we have made the comprehensive countermeasure. According to the results of studying harmonics diagnosis and countermeasure, the following problems are pinpointed: protection of power system double investment space of the field. Therefore, in the initial stage, the countermeasure of harmonics trouble are set up. h a results, the following work has been done: $\circled1$ Generation source of harmonics and it's effect into en power system $\circled2$ Review of law related to harmonics, $\circled3$ Countermeasures to reduce the harmonics

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 추계학술대회 논문집 전력기술부문
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• pp.59-61
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• 2003

This paper demonstrates an analysis of harmonics at the high speed railway substation and proved on this countermeasure using the PSCAD/EMTDC simulation tool. First, high speed railway feeding system is composed using PSCAD/EMTDC electrical railway feeding system model in advance. Second, This paper applications line capacitance values as feeder-trolley, trolley-rail and feeder-rail to analysis harmonics more accuracy in advance did not application. This capacitance values calculate using the EMTP(Electro Magnetic Transient Program). Third, the tractions are arranged in the section that substation supplies power, and this paper take the simulation each case(fractions composition amount) to see harmonic propagation from traction to substation. As a result, generated harmonics at traction can confirmed that harmonics did not reduce at utility source. This harmonics have an influence on bulk power system. Finally, this paper introduces the methods of harmonics effect minimum. This paper proved harmonics reduce effect through the passive filters application.

• 전기학회논문지P
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• 제58권3호
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• pp.257-262
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• 2009

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.

• 조명전기설비학회논문지
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• 제15권2호
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• pp.105-110
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• 2001

본 연구에서는 아파트의 각종 전력설비에서 고조파 실태와 영향을 파악하기 위하여 이를 측정하고 분석하였다. 그 결과 세대에 전력을 공급하는 전등전열변압기에서는 제5고조파, 동력변압기에서는 제5고조파 및 제7고조파가 많이 발생되는 것으로 분석되었다. 또한 아파트 수변전설비의 인입점에서 측정한 전압의 종합왜형률(THD) 은 평균 2.4[%]로서 비교적 양호한 것으로 나타났으나, 향후 가전기기의 대용량화 추세에 따라 아파트의 전력설비 계획에서도 고조파에 대한 고려가 필요한 것으로 분석되었다.

• Journal of Power Electronics
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• 제15권3호
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• pp.819-829
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• 2015

This paper presents a shunt active power filter (SAPF) for compensating inter-harmonics and harmonics when inter-harmonics content is evident in the grid. The principle of inter-harmonics generation in the grid was analyzed, and the inter-harmonics effect on repetitive controllers was discussed in terms of control performance. Traditional repetitive controllers are not applicable in inter-harmonic compensation. Moreover, the effect of an ideal controller on harmonics signals was analyzed on the basis of the internal model principle. The repetitive controller was improved in the form of a basis function according to theoretical analysis. The finite-dimensional repetitive controller, which is also called the multiple-period repetitive controller, was designed for the control of multiple periodic signals. A selective harmonic compensation system was developed with SAPF. This system can be used to compensate harmonics and inter-harmonics in the grid. Finally, system control performance was verified by simulation and experimental results.

• 전기학회논문지
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• 제60권6호
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• pp.1280-1285
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• 2011

Recently, due to the use of fossil fuels for electric power production, carbon emissions increased excessively. Thereby, in order to replace fossil fuels, many studies about fossil fuels such as solar and fuel cell energy source are progressing. Fuel cell system has high energy conversion efficiency. Also, fuel cell system is environmentally friendly system because the carbon emission is almost not occur. Therefore, the fuel cell system is considered as the core technology of in the fields of the future energy and environmental. Fuel cell system has an effect on distribution power system because another power source of other than large power plants. So, fuel cell system can be degradation reason of power quality in the power system. In this paper, we constructed the system for an assessment on harmonics effect. The system is composed with power source, harmonics generation and linear load, fuel cell system. we also performed assessment on harmonics effect in customer and the distributed power system during grid connection of residential fuel cell system. An assessment cases are divided into three. A Case 1 is state that residential load and fuel system are connected to grid, Case 2 is state that residential load and harmonics load are connected to grid, and Case 3 is state that all loads are connected to grid. As a output of fuel cell system is increase, analysis results based on assessment system showed that power quality became more aggravation as effect of harmonics.

• 전기학회논문지P
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• 제59권1호
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• pp.18-23
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• 2010

As the increasing of Non-linear load, we have been growing interest for the harmonics. Harmonics has been focused on the current component rather than voltages. Voltage harmonics can be mainly generated at the PCC with non-linear load and act on voltage unbalance. Voltage harmonics can be enlarged at the capacitor with low impedance as frequency increases. Capacitor is basically used for the power-factor compensation and sometimes as the passive filter. Small voltage of low-order acts on quite a few at the capacitor by the current increase. Capacitor has easily fall under by harmonic components. In this paper, we measured the magnitude and phase angle of asymmetrical voltage with harmonics components at the PCC and calculated with the same condition. we concluded that voltage harmonics of higher order increase each current component but have a little effect on capacitor rating.

• 한국안전학회지
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• 제20권2호
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• pp.67-72
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• 2005

This paper proposes the influences of harmonic current on electrical characteristics of an induction motor. Recently, a power system gets more worse as nonlinear load makes harmonics to affect energy lose of system and shorten lift of machines. In this paper, the electrical effect and THD(Total Harmonic Distortion) of harmonic current to an induction motor which is of great use in the industrial fields are measured and analyzed. A power conversion equipment(inverter) is installed to produce harmonics and variable reactors are installed to reduce the harmonics having an effect on the input terminal. Then the effects of the reactors are measured and analyzed. Also average voltage, current, power and 110 by harmonics are analyzed. The results show that Inn is increased by increasing load of the induction motor and installing reactors. And the harmonics affecting the input terminal are decreased by increasing reactor 3[mH] to 6[mH], however, average power of the induction motor is decreased. Therefore, it is very important that reactors should be carefully installed considering the merits and demerits resulting from the installation of reactors.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 제4회 영호남학술대회 논문집
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• pp.142-145
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• 2002

This paper describes an influence of system voltage harmonics on arrester deterioration diagnostic techniques based on leakage current measurement because the resistive current is composed of two components caused by nonlinear characteristics of arrester and by system voltage harmonics. Resistive leakage currents of arresters, which can be evaluated by the third harmonic component of total leakage currents, increase with its deterioration progress. In this paper, we developed a PSpice model for ZnO arrester to simulate the harmonics' effect described above. In simulation, pure sinusoidal voltage and the $3^{rd}$ harmonic voltage are applied to the model, and the leakage current changes are compared. The simulation results showed that the magnitudes of resistive leakage current depend not only on the phase of system voltage harmonics but also on the magnitude of it.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 하계학술대회 논문집 A
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• pp.12-14
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• 1995

It is necessary to analyze exactly the torque ripple components in the harmonics as to decrease the torque ripple. Lower harmonics influence mainly on torque ripple. Among the harmonics, the pairs of 5's, 7's and 11's, 13's are dominant, and the magnitude of each pairs of current harmonics are very significant. Therefore, for decreasing the torque ripple, current harmonic pairs of 6n ${\pm}$1's orders must be simultaneously eliminated. In the case of eliminating one of current harmonic pairs, even though the magnitude of the current harmonics is small, It has great effect on torque ripple.