• 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 Technologic Dentistry
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• v.36 no.4
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• pp.267-275
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• 2014

Purpose: The purpose of this study is to analyze denture satisfaction by burdened cost types. Methods: All 588 subjects in Gyeongsangnam-do, Korea was surveyed randomly. The study was conducted for about 24 days from March 28th to April 20th, 2014. The objects who participated in the survey were offered self-report questionnaires for this study. Results: Satisfaction with Half Price of the National Health Insurance Support Denture patients appears the highest point of $2.98{\pm}0.22$, and The Governor Pledge Free Denture appears $2.90{\pm}0.17$ the lowest. Also Pay Denture appears $2.96{\pm}0.21$. Provincial authority regulated medical carelessness inefficiently and at all during the procedure, without having to pay the cost of individual. also provincial authority support low budget. This is the result from the lowest satisfaction of The Governor Pledge Free Denture patient. Conclusion: According to the survey results, The Governor Pledge Free Denture and The Total Pay Denture's satisfaction are higher than The National Health Insurance Support Denture. and The National Health Insurance Support Denture are more uncomfortable than pay denture to use.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.40 no.1
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• pp.10-17
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• 1991

An improved control method in turbine control system is proposed. By automatic follow-up design, power system frequency may be maintained within prespecified range. Base or half load control is possible by distributing power plant load allotment. Otherwise, diminutive frequency-load control is dine by governor-free operation in power plant. This paper proposes governor-free operation which is automatically followed by load-limitter setter. The condition which limits governor action may be somewhat improved within boiler condition by this idea. This design has been implemented at Samchunpo thermal power plant. The improved practical results are shown.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.6
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• pp.905-910
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• 2017

As the development of BESS(Battery Energy Storage System), the application of BESS in load frequency control is considered as effective method. So, KEPCO(Korea Electric Power Corporation) have installed about 236MW ESS for GF(Govner Free) function from 2014. In this paper, we implemented Simulink Model for KEPCO GF ESS and analyzed one year historical operation data generated by Simulink model and actually measured frequency data. The operation results were divided into action for maintaining SOC and frequency. In addition, we also analyzed cycle life of GF ESS using two ESS cycle life model. We concluded the ESS cycle life models are not appropriate, because Most of the SOC swing in operation results are below 10%.

• 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.

• KEPCO Journal on Electric Power and Energy
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• v.6 no.2
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• pp.123-127
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• 2020

KEPCO has installed Frequency Regulation ESS (FR ESS) of 376 MW since 2015. Frequency Regulation is ancillary service to support stabilizing system frequency, which is divided into governor free and automatic generation control. KEPCO operates FR ESS as governor free application and leads FR ESS market with capability of diverse demonstration and operation experiences. To expand FR ESS role during transient states of power system, KEPCO has extended operating time of charging and discharging. KEPCO has also changed speed droop lower than before to improve contribution on frequency compensation, and acquired much experiences of differentiating bad cells from others. Based on these technologies and know-hows, KEPCO Research Institutes received request of feasibility study and technical cooperation for overseas FR ESS business. This paper suggests the simple and practical method for making technological feasibility study of FR ESS.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.4 no.3
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• pp.39-54
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• 2009

As of July, 2009, Chungnam Province get DI (Direct Investment) of 2,502 corporations as the amount of 31 billion US dollars only for 3 years. Especially, Chungnam provincial governor make a excessive performance of 2.5 times comparing to the target number, 1,000 of inviting capital, that is public promise in the election. Now, the amount of inviting foreign capital is 1.2 billion dollars, at the end of this year it might be 1.4 billion dollars just in case of making a success on going negotiations. This outstanding performance comes from governor's leadership and aggressive strategies of well-trained subordinates. Chungnam Province has nation-wide multiple targets focused on interdisciplinary industries including strategic industries of display, auto-parts, steel, and oil-chemistry. Also, it has organic network system based on the very descriptive and accurate informations managing the task force team consisted of 35 competent members. In conclusion, the core competence of inviting foreign capital in a regional government is governor's strong leadership, activated organization consisted of specially well trained subordinates, and predominant differentiated strategies in details.

• 전기의세계
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• v.24 no.5
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• pp.97-102
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• 1975

This paper describes the result of a Study for the Optimum Operating method with Spinning reserve in case of outage of large generator unit to improve the system stability and prevent the system frequency drop. This is usually done by governor free operation, so we focused our attention to the operating Char acteristics of spinning reserve. Nexy, a study was made to mesure the upper limit of Spinning reserve and when this upper limit cannot match the required power, a relationship between the amount of spinning reserve and that of the load shedding requirement was searched with regard to several system operating conditions to use it in our future system operation. By this study, the optimum system operating method was recommended for reliable operation of power system.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.52-53
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• 2007

현 CBP(Cost Based Pool)에서 주파수조정은 전기품질유지와 전력계통 안정성 확보에 절대적으로 필요한 계통운영보조서비스의 항목이다. 이는 해외 전력계통에서도 예외없이 채택하여 적용하고 있으며 적극적인 참여를 유도하기 위하여 다양한 비용보상 방안을 시행하고 있다. 순시 주파수조정은 발전기 조속기 특성에 따라 다양한 출력응동특성을 가지고 있으며 이에 따라 계통에 기여하는 바도 달라지게 된다. 따라서 주파수조정에 참여하는 발전기의 계통기여도에 따른 주파수추종운전 능력에 대한 평가를 계량화할 수 있는 방법이 요구된다.

• KEPCO Journal on Electric Power and Energy
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• v.2 no.2
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• pp.227-232
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• 2016

To test the effectiveness of using an energy storage system for frequency regulation, the Energy New Business Laboratory at KEPCO Research Institute installed a 4 MW energy storage system (ESS) demonstration facility at the Jocheon Substation on Jeju Island. And after the successful completion of demonstration operations, a total of 52 MW ESS for frequency regulation was installed in Seo-Anseong (28 MW, governor-free control) and in Shin-Yongin (24 MW, automatic generation control). The control system used in these two sites was based on the control system developed for the 4 MW ESS demonstration facility. KEPCO recently finished the construction of 184 MW ESS for frequency regulation in 8 locations, (e.g. Shin-Gimjae substation, Shin-Gaeryong substation, etc.) and they are currently being tested for automatic operation. KEPCO plans to construct additional ESS facilities (up to a total of about 500 MW for frequency regulation by 2017), thus, various operational tests would first have to be conducted. The high-speed characteristic of ESS can negatively impact the power system in case the 500 MW ESS is not properly operated. At this stage we need to verify how effectively the 500 MW ESS can regulate frequency. In this paper, the effect of using ESS for frequency regulation on the power system of Korea was studied. Simulations were conducted to determine the effect of using a 524 MW ESS for frequency regulation. Models of the power grid and the ESS were developed to verify the performance of the operation system and its control system. When a high capacity power plant is tripped, a 24 MW ESS supplies power automatically and 4 units of 125MW ESS supply power manually. This study only focuses on transient state analysis. It was verified that 500 MW ESS can regulate system frequency faster and more effectively than conventional power plants. Also, it was verified that time-delayed high speed operations of multiple ESS facilities do not negatively impact power system operations. It is recommended that further testing be conducted for a fleet of multiple ESSs with different capacities distributed over multiple substations (e.g. 16, 24, 28, and 48 MW ESS distributed across 20 substations) because each ESS measures frequency individually. The operation of one ESS facility will differ from the other ESSs within the fleet, and may negatively impact the performance of the others. The following are also recommended: (a) studies wherein all ESSs should be operated in automatic mode; (b) studies on the improvement of individual ESS control; and (c) studies on the reapportionment of all ESS energies within the fleet.