• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.12
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• pp.193-200
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• 2010

In this paper, the eigenvalue sensitivity analysis is calculated in the power system which is including both generator controllers such as Exciter, PSS and thyristor controlled FACTS devices in transmission lines such as TCSC. Exciter and PSS are continuously operating controllers but TCSC has a switching device which operates non-continuously. To analyze both continuous and non-continuous operating equipments, the RCF method one of the numerical analysis method in discrete time domain is applied using discrete models of the power system. Also the eigenvalue sensitivity calculation algorithm using state transition equations in discrete time domain is devised and applied to a sampled system. As a result of simulation, the eigenvalue sensitivity coefficients calculated using discrete system models in discrete time domain are changed periodically and showed different values compared to those of continuous system model in time domain by the effect of periodic switching operations of TCSC.

• Journal of Electrical Engineering and Technology
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• v.5 no.1
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• pp.16-20
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• 2010

Recently, the smart grid has become a hot issue and interest in related power sources have increased accordingly. The implementation of a smart grid can enable many generation resources to be linked to the power system, including small-scale reactors for the purpose of co-generation. Research on small-scale reactors is being carried out all over the world. Similarly, Korea is also conducting research on multi-purpose regional energy systems using nuclear energy. This paper proposes a real-time data acquisition and analysis system for small-scale reactors, and is known as the REX-10 (Regional Energy rX 10 MVA). This analysis requires real-time simulations for the power system since it needs data communication with a remote REX-10. A RTDS (Real Time Digital Simulator) has been used for the simulation, and a SCADA/HMI system interfaced with the RTDS is proposed for the purpose of monitoring and control of the regional energy system.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.11
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• pp.1946-1953
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• 2008

Power system of Jeju is interconnected to the mainland using HVDC and that is also interconnected to three wind farms. It will be difficult to control of Jeju power system if HVDC is disconnected or HVDC is overhauled under large scale wind farms interconnected. We measured and analysed the power quality of two substation and two wind farms to assess that wind farms have an effect on Jeju system during the HVDC overhaul last May. We concentrated on the power quality like frequency, voltage variation, voltage harmonics, current harmonics, flicker. We can found that the frequency of Jeju system is very unstable during overhaul, so the frequency of Jeju system can be variated easily by wind farm's rapid output power variation. There are some benefits and weak points in power quality between two wind farms because each wind farm is consist of different wind turbines.

• Proceedings of the KIEE Conference
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• 2006.07a
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• pp.410-411
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• 2006

This paper is focused on the survey on the power system modeling using a clustering algorithm. In electricity markets, clustering method is a efficient tool to model the power system. It can be seen that electricity markets can also be classified into several groups which show similar patterns and that the fundamental characteristics of power systems can be widely applicable to other technical problems in power system such as generation scheduling, power flow analysis, short-term load forecasting, and so on. There are several researches on the power system modeling using a clustering algorithm. We specially surveyed their own clustering methods to model the power system.

• 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 IKEEE
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• v.18 no.3
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• pp.313-319
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• 2014

The objectives of power system operations are to preserve system stability and reliability as well as to supply proper electric power. For an activation of these objectives, voltage and reactive power should be considered. There are a number of types about reactive power sources, and an insertion of shunt capacitor banks are one of the method to support bus voltage adjacent. This paper includes the design procedure to determine the hybrid type capacitor bank configurations on power system to improve stability and reliability. This procedure includes the capacitor bank capacity calculation, reactor type selection, and reactor capacity calculation. The total capacity calculation of capacitor bank is based on the reactive power margin which is calculated through system studies such as, contingency analysis and Q-V analysis. In the second step, the reactor type and its capacity can be determined through the harmonic analysis. This paper shows that the harmonics are decreased by the proposed hybrid type capacitor bank, especially 5th and 7th harmonics.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.04a
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• pp.425-430
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• 2008

To verify the system performance of portable AE leak diagnosis system which can measure with moving conditions, AE activities such as RMS voltage level, AE signal trend, leak rate degree according to AE database, FFT spectrum were measured during operation on total 11 valves of the secondary system in nuclear power plant. AE activities were recorded and analyzed from various operating conditions including different temperature, type of valve, pressure difference, valve size and fluid. The results of this field study are utilized to select the type of sensors, the frequency band for filtering and thereby to improve the signal-to-noise ratio for diagnosis for diagnosis or monitoring of valves in operation. As the final result of application study above, portable type leak diagnosis system by AE was developed. The outcome of the study can be definitely applied as a means of the diagnosis or monitoring system for energy saving and prevention of accident for power plant valve. The purpose of this study is to verify availability of the acoustic emission in-situ monitoring method to the internal leak and operating conditions of the major valves at nuclear power plants. In this study, acoustic emission tests are performed when the pressurized temperature water and steam flowed through glove valve(main steam dump valve) and check valve(main steam outlet pump check valve) on the normal size of 12 and 18 ". The valve internal leak monitoring system for practical field was designed. The acoustic emission method was applied to the valves at the site, and the background noise was measured for the abnormal plant condition. To improve the reliability, a judgment of leak on the system was used various factors which are AE parameters, trend analysis, frequency analysis, voltage analysis and amplitude analysis of acoustic signal emitted from the valve operating condition internal leak.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.6
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• pp.1138-1145
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• 2009

This paper presents an active and reactive power compensator for the wind power system with squirrel-cage induction generator. The output power of a wind power system changes irregularly according to the variation of wind speed. The developed system is able to continuously compensate the active and reactive power. The 3-phase inverter operates for the compensation of reactive power, while the DC/DC converter with super-capacitors operates for the compensation of active power. The operational feasibility of the proposed model was verified by simulations with PSCAD/EMTDC and the feasibility of hardware implementation was confirmed by experimental works with a scaled hardware model. The proposed compensator can be expected that developed system may be used to compensated the abrupt power variation due to sudden change of wind speed or sudden power-drop by tower effect. It can be also applied for the distributed generation and the Micro-Grid.

• Journal of the Earthquake Engineering Society of Korea
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• v.17 no.6
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• pp.245-255
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• 2013

According to natural frequency of soil, characteristics of earthquake responses of an isolated containment building in nuclear power plants are examined. For this, earthquake response analysis of seismically isolated containment buildings in nuclear power plants is carried out by strictly considering soil-structure interactions. The structure and near-field soil are modeled by the finite element method while far-field soil by consistent transmitting boundary. The equation of motion of a soil-structure interaction system under incident seismic wave is derived. The derived equations of motion are solved to carry out earthquake analysis of a seismically isolated soil-structure system. Generally, the results of this analysis show that seismic isolation significantly reduces the responses of the soil-structure system. However, if the natural frequency of the soil is similar to that of the soil-structure system, the responses of the containment buildings in nuclear power plants rather increases due to interactions in the system.

• Journal of Korea Society of Industrial Information Systems
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• v.26 no.1
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• pp.41-54
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• 2021

There is a difficulty in improving the working environment and technological advancement due to power supply through cables in the application of linear motors of robots and transfer systems applied in the existing manufacturing industry. We have studied the shape of the high-frequency coil for contactless power transmission system and characteristics of power conversion system, based on the magnetic field analysis of 2D and 3D, using the FEM-based physical analysis program.