• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 C
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• pp.1510-1513
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• 1999

Carried out simulation for yearly peak and March load time of the KEPCO Power System in 1999. Analysis of the problems in power system operation by powerflow, fault and stability study. Establishment of power system optimal operating plan by installation of power system stabilizer.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 C
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• pp.1472-1474
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• 1999

This paper proposes the estimation method about how much reactive power can be increased or decreased under prescribed bus voltage limits in non-linear reactive power and power flow equations. The static nonlinear reactive power voltage problem can be formulated using a linear resistive(I-V) network with voltage dependent current sources. Linear programming model is derived for finding bounds on reactive power. This method was applied to future Korean power system and proved its effectiveness.

• KEPCO Journal on Electric Power and Energy
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• 제7권2호
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• pp.249-254
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• 2021

As the spreading speed of electric vehicles increases rapidly, those are expected to be able to use them as flexible resources in the power system beyond the concern for the supply of its charging power. Especially when the Renewable Energy sources (RES) which have no intrinsic control capability have replaced the synchronous generators more and more, the power system needs to secure the additional frequency control resources to ensure its stability. However, the feasibility of using electric vehicles as the frequency control resources should be analyzed from the perspective of the power system operation and it requires the existing simulation frameworks for the power system. Therefore, this paper proposes the grid connected modeling of the primary frequency control provided by electric vehicles which can be integrated into the existing power system model. In addition, the proposed model is implemented considering technical performances constrained by the characteristics of the Vehicle-Grid Integration (VGI) system so that the simulation results can be accepted by the power utilities operating the power system conservatively.

• 전기학회논문지
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• 제65권1호
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• pp.31-39
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• 2016

Power system engineers use power systems solution programs such as PSS/E, DSATool, Power World simulators for power system analysis. In this reason, KEPCO has begun to develop independent power system program, KW-PSS(KEPCO World Power system Solution) since 2002 and KW-PSS ver2.0 development was completed in 2011. However, it did not have much better functions compared with other programs. Therefore, we focused on the development of the practical and specialized functions. Consequently, PAZ(Power system AnalyZer) ver3.0 has been developed and it realized a differentiation than previous version. In other words, previous version focused on the basic function of power system analysis, PAZ ver3.0 has implemented many automated functions for power system operators were driven maximize operational efficiency. The unique feature of the implementation is as follows : Automated check for exceeding the breaker capacity, Scheduled outage automation, Control-file wizard for various voltage stability analysis, Scenario-based multiple transient stability analysis and Auto calculation of transmission line impedance. As shown in these functions, Those functions provide to use power system analysis easily by automation and simplification for power system engineers. We will secure national expertise through PAZ ver3.0. In addition it will be able to gain competitive edge through the steady development in the world market.

• KEPCO Journal on Electric Power and Energy
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• 제6권3호
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• pp.279-284
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• 2020

This paper presents the conceptual design of a cooperative control with Energy Management System (EMS) and Distribution Management System (DMS). This control enables insufficient reactive power reserve in a power transmission system to be supplemented by surplus reactive power in a power distribution system on the basis of the amount of the needed reactive power reserve calculated by the EMS. This can be achieved, because increased numbers of microgrids with distributed energy resources will be installed in the distribution system. Furthermore, the DMS with smart control strategy by using surplus reactive power in the distribution system of the area has been gradually installed in the system as well. Therefore, a kind of hierarchical voltage control and cooperative control scheme could be considered for the effective use of energy resources. A quantitative index to evaluate the current reactive power reserve of the transmission system is also required. In the paper, the algorithm for the whole cooperative control system, including Area-Q Indicator (AQI) as the index for the current reactive power reserve of a voltage control area, is devised and presented. Finally, the performance of the proposed system is proven by several simulation studies.

• Journal of Electrical Engineering and Technology
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• 제5권3호
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• pp.400-406
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• 2010

This paper deals with parameter tuning of the Power System Stabilizer (PSS) for 612 MVA thermal power plants in the KEPCO system and its validation in a field test. In this paper, the selection of parameters, such as lead-lag time constants for phase compensation and system gain, is optimized using linear and eigenvalue analyses. This is then verified through the time-domain transient stability analysis. In the next step, the performance of PSS is finally verified by the generator's on-line field test. After the field test, measured and simulated data are also compared to prove the effectiveness of the models used in the simulations.

• KEPCO Journal on Electric Power and Energy
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• 제5권4호
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• pp.349-359
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• 2019

This paper introduces a wind turbine simulation system based on the IEC 61400-25 standard to simulate different kinds of wind turbines. A unified communication protocol was required for monitoring and control of wind turbines, because manufacturers had used their own protocols for their turbines. As a result of such an effort, the international standard IEC 61400-25 was established. To implement the schema of IEC 61400-25, the IEC61850 SCL was modified and applied to the simulation system, which enabled the system to be compatible with heterogeneous wind turbine information models. The developed simulation system can be used for interoperability tests with a new type of wind turbine information model.

• KEPCO Journal on Electric Power and Energy
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• 제5권2호
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• pp.67-74
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• 2019

최근 신재생 분산전원의 투입 확대로 배전계통 내 변동성이 커짐에 따라서 안정적인 배전계통 운영에 대한 우려가 커지고 있는 상황이다. 미래 배전계통의 효율적인 관리를 위해서 새로운 시각화 기술을 이용한 배전계통 운영시스템의 개선이 필요하다. 본 논문에서는 배전분야의 GIS 도입 현황과 관련 기술 동향을 기술하고, 배전계통 운영을 위해 GIS시스템의 필요성과 GIS기술 도입 시 해결해야할 문제점을 분석한다.

• KEPCO Journal on Electric Power and Energy
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• 제1권1호
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• pp.141-144
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• 2015

The superconducting fault current limiter (SFCL) is an electric power device that limits the fault current immediately in a power grid. Korea Electric Power Corporation (KEPCO) has been developing a 154 kV, 2 kA SFCL since 2011 to protect power grids from increasing fault current and improve the stability and quality of electric power. This SFCL adopts 2G YBCO wires and operates at 71 K and 5 bars. In this paper, a cooling system for the 154 kV SFCL and its cooling test results are reported. This cooling system uses a Stirling-type cooler to make sub-cooled liquid nitrogen ($LN_2$), which cools the superconductor modules of the SFCL. The $LN_2$ is circulated between the cooler and the cryostat that contains superconductor modules. The $LN_2$ also plays the role of a high voltage insulator between the modules and the cryostat, so the pressure was maintained at 5 bars for high insulation performance. After installation in a test site, the cooling characteristics of the system were tested. In this operation test, some important data were measured such as temperature distribution in $LN_2$, pressure change, performance of the heat exchanger, and cooling capacity of the total system. Consequently, the results indicate that the cooling system operates well as designed.

• KEPCO Journal on Electric Power and Energy
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• 제1권1호
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• pp.99-104
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• 2015

In this study, it has been initiated to investigate the specific abnormal vibration signal that has been captured in the power equipment. Array Microphone can be used in order to detect the direction and the position of the noise source. It is possible to track the abnormal mechanical noise in the power plant by utilizing the program and the microphone array system developed from this research. Array microphone system can be operated as a constant monitoring system.