• Proceedings of the KIEE Conference
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• 1994.07a
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• pp.351-353
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• 1994

The solar cell should be operated at the maximum power point every instant. Because this maximum power point is fluctuating due to the change in the insolation and temperature. In this paper, we propose a new maximum power' point tracker by using the microprocessor. The proposed step-down chopper system tracks always the maximum power point, regardless of the change in the insolation, temperature and load.

• KEPCO Journal on Electric Power and Energy
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• v.6 no.1
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• pp.35-40
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• 2020

The purpose of this paper is to improve the grounding point measurement method for the maintenance of the earth resistance of the distribution line. This study defines the correlation among humidity of the soil, the earth resistivity and the grounding resistance. Based on the results of the study, the grounding resistance value measurement should be limited to the location where the earth resistivity change is large, and the measurement time and cost can be greatly reduced.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.52 no.8
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• pp.437-443
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• 2003

In this paper an expert system is developed to decide the resetting area of protective devices in power transmission systems. A configuration change in power transmission networks from a substation extension such as new line or bus addition need resetting of protective devices around the point of configuration changes. To find the resetting area in complex power system is very difficult, especially when the distance protective relays are considered to be reset. The proposed expert system, in this paper to find the resetting area has many rules based on the changes of fault currents and apparent factors from the power system alteration. It solves the problem to find relay resetting area using the network information in the database and the rule-base. The case study shows a result of the problem to find relay resetting area in KEPCO system when there is any configuration change.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.54 no.4
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• pp.208-216
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• 2005

Recently, the study of islanding phenomenon, maintains its operation even when the utility grid is removed has lead to the trend of utility interactive inverters in photovoltaic generation systems. In this paper, a novel Anti-islanding method is presented. the proposed method can keep the real average power component constant by MPPT control and cause the load current frequency with only change of reactive power component under the islanding condition. its periodical change of Reactive power component can decrease the NDZ(Non-Detective zone) so that the detection of various loads will be possible. the insufficient effect if additional reactive power component to the grid is proved theoretically and the islanding detection is also confirmed from a experimental result with a inverter for 3kW photovoltaic generation system applied the proposed Anti-islanding method.

• Proceedings of the KIPE Conference
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• 2002.11a
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• pp.74-77
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• 2002

Combined generation system of Photovoltaic and wind generation have shortcoming that is different output power according to change of weather. So, the combined generation system is required backup system that such as a storage battery to supply energy, when not enough photovoltaic and wind power source for power supply equally and continually, because the energy source is changeable and stable through change of weather as irradiation, temperature, wind speed, wind direction, seasons, etc..

• Proceedings of the Korean Nuclear Society Conference
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• 1997.05b
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• pp.433-438
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• 1997

It Is necessary to calculate radwaste effluent due to change in the fuel defect rate to see the overall change in radwaste effluent md, at present, for this type of calculation DAMSAM code is being used. However, often, one can not access easily to this code with many reason and so we have chosen this case, in this paper, to show a very simplified but quite accurated calculation method without the solving equations. The physical meanning of the parameters in the equations used in DAMSAM have been reviewed to simplify the equations and the result calculated with this method have been compared with that of DAMSAM.

• Communications for Statistical Applications and Methods
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• v.16 no.3
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• pp.511-518
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• 2009

We consider the problem of testing for change and estimating the unknown change-point in a sequence of time-ordered observations from the binomial and Poisson distributions. Including the likelihood ratio test, Gombay and Horvath (1990) tests are studied and the proposed change-point estimator is derived from their test statistic. A power study of tests and a comparison study of change-point estimators are done via simulation.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.19 no.1
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• pp.109-116
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• 2005

Wind power and photovoltaic(PV) systems are getting into the spotlight as substitute energy. But problem is happened stability by speed change of wind and the power output of the sun's ray. The power output amount according to velocity of wind power system. System breakdown can happen at change of sudden velocity, typhoon and night. This paper shows a automatic tail safety brake controller based on feedback control using wind velocity. The operation of automatic tail safety controller verified by manual test. PV system is a energy change system by temperature of sun's ray and cell. Maximum power point tracking(MPPT) is used in PV systems to maximize the photovoltaic array output power. In existed PV system is low output and changeable DC voltage for boost and filtering the buck-boost converter use. But, this paper established deformed DC-DC converter. Changed Buck-boost converter's unlined output current to line output current using DC-DC converter. This is effect that reduce ripple of output current. Proved through an output waveform comparison experiment. Finally, tail safety brake controller is established to wind turbine system for stability elevation and DC-DC converter is established on PV system for stability output.

• Journal of Advanced Navigation Technology
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• v.24 no.4
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• pp.291-298
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• 2020

This study proposed a model that can track MPP faster than the existing MPPT algorithm using the particle swarm optimization algorithm (PSO). The proposed model highly sets the acceleration constants of gbest and pbest in the PSO algorithm to quickly track the MPP point and eliminates the power instability problem. In addition, this algorithm was re-executed by detecting the change in power of the solar panel according to the rapid change in solar radiation. As a result of the experiment, MPP time was 0.03 seconds and power was 131.65 for 691.5 W/m2, and MPP was tracked at higher power and speed than the existing P&O and INC algorithms. The proposed model can be applied when a change in the amount of power is detected by partial shading in a Photovoltaic power plant with Photovoltaic connected in parallel. In order to improve the MPPT algorithm, this study needs a comparative study on optimization algorithms such as moth flame optimization (MFO) and whale optimization algorithm (WOA).

• IEMEK Journal of Embedded Systems and Applications
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• v.1 no.1
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• pp.1-7
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• 2006

In this paper, a novel power management structure for an energy harvesting pervasive system is proposed. The system considers the power state of each subsystem to assign proper power sources. The switch matrix structure utilizes each power source to reduce the peak current of the battery. The power management structure can be interfaced to an embedded system power supply without significant design change.