• KEPCO Journal on Electric Power and Energy
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• v.5 no.2
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• pp.113-120
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• 2019

We have developed 1 kW-class PEMFC-battery hybrid system independently powering to the building, through the process of system design, current load characteristics analysis, power system configuration for demonstration site and performance evaluation. In order to use the fuel cell and battery as the hybrid type, a control technology for the charging/discharging decision and charging speed of the battery is required rather than using fuel cell. Also output power distribution between PEMFC and the battery is a core of energy management technology. It is confirmed that it is possible to supply independently 1kW powering the building to ensure optimal energy management through the power control experiment of the hybrid system.

• Journal of Electrical Engineering and Technology
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• v.1 no.4
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• pp.409-413
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• 2006

This paper deals with the design and testing of a simulator system for microgrids with distributed generations. This system is composed of a Real Time Digital Simulator (RTDS) and a power amplifier. The RTDS parts are operated for real time simulation for the microgrid model and the distributed generation source model. The power amplifiers are operated fur amplification of the RTDS's simulated output signal, which is a node voltage of the microgrid and distributed generation source. In this paper, we represent an RTDS system design, specification and test results of a power amplifier and simulation results of a PV (Photovoltaic) system and wind turbine system. The proposed system is applicable for development and performance testing of a PCS (Power Conversion System) for renewable energy sources.

• Journal of Electrical Engineering and Technology
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• v.1 no.1
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• pp.23-27
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• 2006

In this paper a Hybrid Real Time HVDC Simulator fur both operator Training and Researching in the Cheju-Haenam HVDC System is proposed and its performance is studied by means of RTDS (Real Time Digital Simulator), EMTDC (Electro-Magnetic Transients system for DC), PSS/E (Power System Simulator for Engineering), and experienced scenarios. The objective of this paper is to represent the strategy in development for KEPCO's hybrid HVDC simulator for the Cheju-Haenam HVDC system. This simulator consists of two DC stations, DC cables, external digital/analog controllers, monitoring systems and control desk for education, and AC networks. Its suitability for operator's education is tested during startup/shutdown and normal state operations. Dynamic performances of it are also verified.

• Journal of the Korean Solar Energy Society
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• v.34 no.1
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• pp.81-90
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• 2014

The Jeju-Korea power system is a small-sized network with a system demand ranging from a autumn minimum of 350MW to a summer peak of 716MW. Because Jeju island is well exposed to north-east winds with high speed, applications to connect to Jeju power system are flooded. Considering physical/environmental constraints, Jeju Self-governing Province has also target for the wind power capacity of 1,350MW by 2020. It amounts to two or three times of Jeju average-demand power and wind power limit capacity announced by Korea Power Exchange (KPX) company. Wind farm connection agreements will be signed to maximize utilization of wind resource. In spite of submarine cable HVDC connected to Korea mainland, Jeju power system is independently operated by frequency and reserve control. This study reevaluates wind power limit based on the KPX criteria from 2016 to 2020. First of all wind power generation limit are affected by off-peak demand in Jeju power system. Also the possibility capacity rate of charging wind power output is evaluated by using energy storage system (ESS). As a result, in case of using 110MWh ESS, wind power limit increases 33~55MW(30~50% of ESS), wind power constraint energy decreases from 68,539MWh to 50,301MWh and wind farm capacity factor increases from 25.9 to 26.1% in 2020.

• Proceedings of the KIEE Conference
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• summer
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• pp.64-66
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• 2004

Due to the involvedness of power system, the analysis of power system is hard to make out. In some cases, visualized analysis results help to understand the power system effectively. In this paper, 3D graphic is used to visualize the power system, and chains of power system's changes are represented using the result of HyperSim, a real-time simulator. We represent states of each bus by changing height and colors of cylinder. The current of transmission lines and the angle of generators are represented by the size of pyramids and the drection of arrows respectively. Results of power system analysis are represented more easily and more intuitably using the visualization.

• Proceedings of the KIEE Conference
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• 2003.07a
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• pp.163-165
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• 2003

In order to improve the power restoration capability of system operators In case that the fault and blackout happen in the power system, Development of the Power Restoration Training System is necessarily required as a simulator tool for training operator. Owing to these reasons, KEPRI has developed the power restoration training system and graphic editor and applied it to Jeju transmission system. This paper presents the design and implementation of the system, and shows a example to simulate the primary restorative line in jeju.

• Journal of Electrical Engineering and Technology
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• v.5 no.2
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• pp.191-196
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• 2010

Power system restoration following a massive or complete blackout starts with energizing the primary restorative transmission system. During this primary restoration process, unexpected overvoltage may happen due to nonlinear interaction between the unloaded transformer and the transmission system. In the case of the Myanmar electric power system, there are so many wide outage experiences, including complete blackout cases, caused by 230kV line faults and so on. Consequently, Myanmar's system operators have been well trained to deal with wide blackouts. Howver, system blackout restoration has been conducted by relying on the experience of only a few specialists. So, more scientific analysis is required to meet the requirements necessary to ensure fast and reliable system restoration. This paper presents analytical results on the primary restorative transmission system of Myanmar, focusing on the problems during the early restoration process. Methodologies are presented that handle load pick-up, terminal voltage and the reactive capability limitation of black-start generators to compensate the Ferranti effect. Static and dynamic simulation with the PSSolution and EMTDC programs respectively for the six cases are performed in order to select the primary restorative transmission lines.

• Proceedings of the KIEE Conference
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• 1990.11a
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• pp.384-387
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• 1990

This paper describes the design of the power conversion system for the 3-ton prototype magnetic levitation system. Electric power needed for the propulsion and levitation system of the vehicle is supplied by the wayside rectifier through the power rail and is picked up by the on board power collector, and is supplied to the propulsion VVVF inverter and levitation chopper. In this paper, design characteristic of the VVVF inverter, chopper and power source unit which provides control power to the levitation controller and levitation power to the chopper is described.

• Proceedings of the KIEE Conference
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• 2008.11a
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• pp.197-199
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• 2008

중장기 전력계통의 신뢰도는 공급지장 에너지를 분석함으로써 평가할 수 있는데 이를 위해서는 발전설비와 송전설비의 정확한 비가용률 산정이 필수적이다. 본 논문에서는 우리나라의 발전기 비가용률과 송전선로 비가용률을 산정하고 이를 이용하여 중장기 전력계통의 공급지장 에너지의 추이를 분석한다.

• Proceedings of the KIEE Conference
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• 2000.11a
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• pp.39-42
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• 2000

In stressed power system, due to the presence of increased nonlinearity and the existence of nonlinear modal interactions, there exist some limitations to the use of conventional linear system theory to identify the optimum sites for controller. This paper proposes an approach to identify the optimum sites for controller using the method of normal forms. In this paper nonlinear participation factor and coupling factor are proposed as a measures of identification of optimum sites for controller and a selection procedure is also proposed. The proposed procedure is applied to the 10-generator New England System and the KEPCO System in the year of 2010 to illustrate its capabilities.