• Journal of Electrical Engineering and Technology
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• v.8 no.4
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• pp.667-674
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• 2013

Wind power producers face many regulation costs in deregulated environment, which remarkably lowers the value of wind power in comparison with conventional sources. One of these costs is associated with the real-time variation of power output and being paid in frequency control market according to the variation band. This paper presents a new approach to coordination of battery energy storage in wind generation system for reducing the payment in frequency control market. The approach depends on the statistic data of wind generation and the prediction of frequency control market price to determine the optimal variation band which is then kept by the real-time charging and discharging of batteries, ultimately the minimum cost of frequency regulation can be obtained. The optimization problem is formulated as trade-off between the decrease in the regulation payment and the increase in the cost of using battery, and vice versus. The approach is applied to a study case and the results of simulation show its effectiveness.

• Proceedings of the KIPE Conference
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• 2013.11a
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• pp.125-126
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• 2013

ESS(Energy Storage System) for Improve the quality of the power grid, supply reliability, system stability and the efficient operation method of power is drawing attention. According to changes in the load of the power system frequency will be adjustable in real time in response to changes in the frequency of the grid, so thermal power output is mainly controlled in order to keep the grid frequency stable. ESS for adjusting the frequency of the grid when the frequency rises to grid and charge the energy storage device. If the frequency drops to discharge the battery power to the grid and the future is expected to replace the thermal power plant. This paper describes 4MW ESS for the frequency regulation and find out about the characteristics through the PSCAD/EMTDC.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.1
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• pp.16-22
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• 2015

As the development of Battery Energy Storage System(BESS) and the increasing of intermittent energy sources like wind power and photovoltaic, the application of BESS in load frequency control is considered as an effective method. To evaluate the effectiveness of BESS application in frequency control, we defined a governor free model of BESS to conduct dynamic simulation. Using the BESS dynamic model, we implemented the power system dynamic model including steam, gas and hydro turbine generators. In this paper we study the control performance of BESS in primary frequency control. The effect of BESS speed regulation rate and response time on governor free operation is investigated. In addition, we compared BESS from steam turbine generator in view point of frequency regulation.

• Journal of information and communication convergence engineering
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• v.6 no.3
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• pp.301-304
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• 2008

This paper presents a lossless inductor snubber-assisted series resonant high frequency inverter using the trench gate IGBTs for the electromagnetic induction eddy current-heated fixing roller in copy and printing machines in a new generation. This soft switching high-frequency inverter can completely achieve zero current soft switching (ZCS) commutation mode transitions and wide power regulation under its constant frequency pulse density modulation (PDM) scheme. Its transient and steady state operating principle is originally presented for a constant frequency PDM strategy under a ZCS operation, together with its output power regulation characteristics-based on the pulse density modulation. The effectiveness of this soft switching high-frequency inverter is confirmed for the fixing equipment with the induction-heated fixing roller.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.28 no.2
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• pp.113-119
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• 2017

In this paper, we have shown the performance analysis results of the LoRa low power wide area network under duty cycle local regulation in Korean RFID/USN frequency band. Especially, we analyzed uplink throughput and data transmission time of a single LoRa end device. From the analysis results, duty cycle regulation, in which a data transmission should be ended within 0.4 second, limits the performance of LoRa network. Therefore, it is necessary to revise Korea's duty cycle regulation referencing EU regulation in order to assess LoRa network in Korea.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.10
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• pp.1483-1494
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• 1993

Most studies analyse the frequecny polities intuitively based on the assumptin that there is no question in the frequency regulation by the government. But this paper started from the concept of frequency as economic goods. This paper conclude that frequency regulation by the government is needed to redistribute the economic surplus causing excessive demand. There are five methods in the frequency assignment-comparative healing, auction, lottery, Joint consortium and pioneer preference. The five methods are studied form the view of welfare economics and the respective political Implications are proposed in this paper.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.54 no.11
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• pp.540-547
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• 2005

One of the roles of AGC is to regulate the frequency of power systems. AGC is also used to control the frequency of Korean Power System. AGC control strategies depend on system characteristics and the requirements of the systems to which those are applied. Korean Power System consists of one control area and does not have tie-lines. In this research, an AGC control strategy is suggested to avoid conflict with governor dynamics and to enhance frequency recovery It shows good performance for regulation and frequency recovery. This control strategy is expected to be applied to New EMS in KPX to get reasonable AGC regulation and frequency recovery performance.

• KEPCO Journal on Electric Power and Energy
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• v.4 no.2
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• pp.107-114
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• 2018

In recent years, ESS (Energy Storage System) has been widely used in various parts of a power system. Especially, due to its fast response time and high ramp rate, ESS is known to play an important role in regulating grid frequency and providing rotational inertia. As the number of installed and commercially operating ESSs increases, the reliability becomes an important issue. This paper introduces control schemes and presents its test method for grid-connected ESS for primary frequency regulation. The test method allows to verify the control operation in the individual operation mode and state. A validation of the method through actual ESS test in a electrical substation is presented in the case study section.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.66 no.2
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• pp.63-68
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• 2017

This paper proposes a new non-isolated DC conversion circuit topology of the voltage source coupled inductor series resonant high-frequency PFM controlled boost chopper type DC-DC power converter using two in one IGBT power module, which can efficiently operate under a principle of zero current soft switching for wide output regulation voltage setting ranges and wide fluctuation of the input DC side voltage as well as the load variation ranges. Its steady state operating principle and the output voltage regulation characteristics in the open-loop-based output voltage control scheme without PI controller loop are described and evaluated from theoretical and experimented viewpoints. Finally, in this paper the computer-aided simulation steady-state analysis and the experimental results are presented in order to prove the effectiveness and the validity of voltage regulation characteristics of the proposed series resonant zero current soft switching boost chopper type DC-DC power converter circuit using IGBTs which is based on simple pulse frequency modulation strategy more than, 20kHz.

• Proceedings of the KIEE Conference
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• 2005.07a
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• pp.298-300
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• 2005

전력계통의 주파수조정예비력(Frequency Regulation Control)은 부하 변동에 대응하여 규정된 주파수를 유지하고 안정된 전력계통 운영이 가능하도록 단시간 내에 응동할 수 있는 예비력이다. 본 논문은 우리나라 전력계통에 적합한 위와 같은 주파수조정예비력을 제시하고 전력산업 구조개편에 따라 분리된 발전사업자들이 전력시장에서 대부분의 주파수조정예비력을 담당하는 화력발전소 예비력 확보 방안을 연구 검토한 것이다.