• Title/Summary/Keyword: Frequency Regulation

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Optimal Coordination of Charging and Frequency Regulation for an Electric Vehicle Aggregator Using Least Square Monte-Carlo (LSMC) with Modeling of Electricity Price Uncertainty

  • Lee, Jong-Uk;Wi, Young-Min;Kim, Youngwook;Joo, Sung-Kwan
    • Journal of Electrical Engineering and Technology
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    • v.8 no.6
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    • pp.1269-1275
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    • 2013
  • Recently, many studies have suggested that an electric vehicle (EV) is one of the means for increasing the reliability of power systems in new energy environments. EVs can make a contribution to improving reliability by providing frequency regulation in power systems in which the Vehicle-to-Grid (V2G) technology has been implemented and, if economically viable, can be helpful in increasing power system reliability. This paper presents a stochastic method for optimal coordination of charging and frequency regulation decisions for an EV aggregator using the Least Square Monte-Carlo (LSMC) with modeling of electricity price uncertainty. The LSMC can be used to assess the value of options based on electricity price uncertainty in order to simultaneously optimize the scheduling of EV charging and regulation service for the EV aggregator. The results of a numerical example show that the proposed method can significantly improve the expected profits of an EV aggregator.

Experimental investigation into infrasound and low-frequency noise radiation characteristics from large wind turbines (중대형 풍력터빈의 저주파 및 초저주파 소음 방사 특성에 대한 실험적 고찰)

  • Lee, Seung-Yub;Cheong, Cheol-Ung;Shin, Su-Hyun;Jung, Sung-Soo;Cheung, Wan-Sup
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2007.11a
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    • pp.1482-1489
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    • 2007
  • In this paper, characteristics of infrasound and low-frequency noise emission from large modern wind turbines are experimentally investigated. The sound measurement procedures of IEC 61400-11 and ISO 7196 are utilized to field test and evaluation of noise emission from each of 1.5 MW and 660 kW wind turbines using the stall regulation and the pitch control for the power regulation, respectively. It was found that the G-weighted SPLs of low-frequency noise including infrasound shows positive correlation with the wind speeds, irrespective of methods of power regulation. This highlights the potential complaint of local community against the infrasound and low-frequency noise of wind turbines. The comparison of measured data with the existing hearing thresholds and criteria curves shows that it is highly probable that the low-frequency noise from the 1.5 MW and 660 kW wind turbines in the frequency range over 30 Hz leads to the psychological complaint of ordinary adults, and that the infrasound in the frequency range from 5 Hz to 8 Hz causes the complaint by rattling the house fitting such as doors and windows.

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Pulse Density Modulated Zero Voltage Soft-Switching High-Frequency Inverter with Single Switch for Xenon Gas Dielectric Barrier Discharge Lamp Dimming

  • Sugimura, Hisayuki;Suh, Ki-Young;Lee, Hyun-Woo;Nakaoka, Mutsuo
    • Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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    • 2006.05a
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    • pp.391-394
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    • 2006
  • This paper presents soft switching zero voltage switching high frequency inverter for rare gas fluorescent lamp using dielectric-barrier discharge phenomenon. The simple high-frequency inverter can completely achieve stable zero voltage soft switching (ZVS) commutation for wide its output power regulation ranges and load variations under its constant high frequency pulse density modulation (PDM) scheme. Its transient and steady state operating principle is originally described and discussed for a constant high-frequency PDM control strategy under a stable ZVS operation commutation, together with its output effective power regulation characteristics-based on the high frequency PDM strategy. The experimental operating performances of this high frequency Inverter are illustrated as compared with computer simulation results and experimental ones. Its light dimming characteristics due to power regulation scheme are evaluated and discussed on the basis of simulation and experimental results. The feasible effectiveness of this high frequency inverter appliance implemented here is proven from the practical point of view.

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Performances of Li-Ion Batteries Using LiNi1-x-yCoxMnyO2 as Cathode Active Materials in Frequency Regulation Application for Power Systems

  • Choi, Jin Hyeok;Kwon, Soon-Jong;Lim, Jungho;Lim, Ji-Hun;Lee, Sung-Eun;Park, Kwangyong
    • KEPCO Journal on Electric Power and Energy
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    • v.6 no.4
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    • pp.461-466
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    • 2020
  • There are many application fields of electrical energy storage such as load shifting, integration with renewables, frequency or voltage supports, and so on. Especially, the frequency regulation is needed to stabilize the electric power system, and there have to be more than 1 GW as power reserve in Korea. Ni-rich layered oxide cathode materials have been investigated as a cathode material for Li-ion batteries because of their higher discharge capacity and lower cost than lithium cobalt oxide. Nonetheless, most of them have been investigated using small coin cells, and therefore, there is a limit to understand the deterioration mode of Ni-rich layered oxides in commercial high energy Li-ion batteries. In this paper, the pouch-type 20 Ah-scale Li-ion full cells are fabricated using Ni-rich layered oxides as a cathode and graphite as an anode. Above all, two test conditions for the application of frequency regulation were established in order to examine the performances of cells. Then, the electrochemical performances of two types of Ni-rich layered oxides are compared, and the long-term performance and degradation mode of the cell using cathode material with high nickel contents among them were investigated in the frequency regulation conditions.

Fatigue and Fatigue-Regulation Behaviors of Undergraduates in Courses Related to Public Health and Undergraduates in Courses not Related to Public Health (보건계열 대학생과 비보건계열 대학생의 피로와 피로조절행위)

  • Choi, Jung
    • Journal of Korean Academy of Fundamentals of Nursing
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    • v.16 no.1
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    • pp.83-91
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    • 2009
  • Purpose: The purpose of this study was to compare fatigue and fatigue-regulation behaviors in undergraduates courses related to public health (group A) and undergraduates in courses not related to public health (group B). Method: Using a structured questionnaire, data were collected from 236 undergraduates. Descriptive statistics, Pearson correlation coefficient, t-test with SAS package were used for data analysis, Results: There was a statistically significant difference between group A and group B in t-test comparison by group for fatigue, and all subcategories of fatigue and fatigue-regulation behaviors. The frequency of fatigue-regulation behavior of group A was 12.23 and the mean for total efficiency of fatigue-regulation behavior was 2.17, while the frequency of fatigue-regulation behavior for group B was 10.47 and the mean for total efficiency of fatigue-regulation behavior was 1.75. Finally, total fatigue and all subcategories of fatigue were positively related to fatigue-regulation behaviors. Conclusion: It is necessary to develop an intervention program for regulating fatigue in undergraduates courses related to public health.

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Influence of Frequency on Electromagnetic Field of Super High-Speed Permanent Magnet Generator

  • Qiu, Hongbo;Wei, Yanqi;Wang, Wei;Tang, Bingxia;Zhao, Xifang;Yang, Cunxiang
    • Journal of Power Electronics
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    • v.19 no.4
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    • pp.980-988
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    • 2019
  • When compared with traditional power frequency generators, the frequency of a super high-speed permanent magnet generator (SHSPMG) is a lot higher. In order to study the influence of frequency on the electromagnetic field of SHSPMGs, a 60000rpm, 117kW SHSPMG was taken as a research object. The two-dimensional finite element model of the generator was established, and the two-dimensional transient field of the generator was simulated. In addition, a test platform of the generator was set up and tested. The reliability of the simulation was verified by comparing the experiment data with that of the simulation. Then the generator electromagnetic field under different frequencies was studied, and the influence mechanism of frequency on the generator electromagnetic field was revealed. The generator loss, voltage regulation rate, torque and torque ripple were analyzed under the rated active power load and different frequencies. The influences of frequency on the eddy current density, loss, voltage regulation rate and torque ripple of the generator were obtained. These conclusions can provide some reference for the design and optimization of SHSPMGs.

SOC-based Control Strategy of Battery Energy Storage System for Power System Frequency Regulation (전력계통 주파수조정을 위한 SOC 기반의 배터리 에너지저장장치 제어전략)

  • Yun, Jun Yeong;Yu, Garam;Kook, Kyung Soo;Rho, Do Hwan;Chang, Byung Hoon
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.63 no.5
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    • pp.622-628
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    • 2014
  • This paper presents the SOC-based control strategy of BESS(Battery Energy Storage System) for providing power system frequency regulation in the bulk power systems. As the life cycle of BESS would be shortened by frequent changes of charge and discharge required for frequency regulation in a steady state, the proposed algorithm operates BESS within a range of SOC where its life cycle can be maximized. However, during a transient period of which occurrence frequency is low, BESS would be controlled to use its full capacity in a wider range of SOC. In addition, each output of multiple BESS is proportionally determined by its SOC so that the balance in SOC of multiple BESS can be managed. The effectiveness of the proposed control strategy is verified through various case studies employing a test system. Moreover, the control result of BESS with the measured frequency from a real system shows SOC of BESS can be maintained within a specific range although the frequency deviation is biased.

Comparison of Compensation Rules for Fast Responding Resources Providing Frequency Regulation Service in Domestic and North American ISO/RTO Power Electricity Market (속응자원의 국내 및 북미 ISO/RTO 주파수조정예비력 서비스 제공에 따른 보상규칙 비교 분석)

  • Park, Dae-Hyun;Park, Yong-Gi;Park, Jong-Bae;Kim, Balho H.;Roh, Jae-Hyung
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.67 no.5
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    • pp.617-625
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    • 2018
  • Since FERC order 755 was published, each frequency regulation market rules of the North American ISO/RTO have been revised in many parts. In 2016, the domestic CBP market has also changed its market rules to allow ESS to participate in the frequency regulation reserve services(Governor Free and Automatic Generation Control). This paper compares and analyzes the changed North American ISP/RTO market and domestic CBP market rules. In particular, we compare PJM and CAISO frequency regulation market pricing mechanism and settlement rules with the settlement rules of the domestic CBP market and compare the factors of each market used to compensate the participating resources in terms of resource dependency and accuracy.

Optimal Dispatch of Energy and Frequency Regulation Reserve Considering Contingency in a Competitive Electricity Market (경쟁적 전력시장에서 상정사고를 고려한 에너지와 주파수 제어예비력의 최적배분 기법)

  • Lee, Ki-Song;Jeong, Yun-Won;Shin, Joong-Rin;Chun, Yeong-Han;Park, Jong-Bae
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.55 no.5
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    • pp.202-213
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    • 2006
  • This paper presents a new approach for optimal dispatch of energy and frequency regulation reserve considering contingency in a competitive electricity market. It is necessary to introduce the reserve market with the spot energy market for operating efficiently and obtaining the security of the electricity market. However, the reserve market is closely connected with the energy market since the energy and reserve are produced from the same resources. Thus, it is inevitable to co-optimize the energy and ancillary service for efficient operation of energy and ancillary service market. Therefore, this paper proposes a new method for optimal dispatch of energy and frequency regulation reserve considering n-1 contingency of generator and transmission line using constraints and sensitivity based on AC power flow To verify the effectiveness of the proposed method, the numerical studies have been performed for 5-bus sample system and modified IEEE 14-bus system.

Development and Demonstration of Trial-run Automation System of Energy Storage System for Frequency Regulation (주파수조정용 에너지저장장치 시운전 자동화 시스템의 개발과 실증)

  • Lim, Geon-Pyo;Choi, Yo-Han;Lee, Seung-Min;Park, Chan-Wook
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.66 no.3
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    • pp.110-116
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    • 2017
  • System to automate the trial-run of energy storage system for frequency regulation was developed and demonstrated. Basic strategy was developed on the basis of trial-run procedure and verified in the computer simulation tool. The algorithm was developed and coded for 4MW trial-run automation system. 4MW trial-run automation system was connected to 4MW energy storage system for frequency regulation in Jocheon substation of Jeju city and demonstrated. 24MW trial-run automation system was developed on the basis of 4MW trial-run automation system and verified by operation system for 24MW energy storage system for frequency regulation. The operation system has own simulation model of energy storage system and power system. The verification was performed to improve the system in the view of user. 24MW trial-run automation system was demonstrated in 32MW Ul-san and 36MW Non-gong energy storage system. All tests of trial-run was done by manual and first they ware taken 1 week with no trial-run automation system. The manual trial-run tests were taken by maximum three times. Trial-run test by trial-run automation system was taken 2 days. The system helps reduce the trial-run test period and improve the accuracy of tests.