• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.451-452
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• 2011

최근 들어 전력공급의 신뢰성 강화를 위해 고장을 미리 진단할 수 있는 기술이 요구되고 있다. 전력IT 국책과제로 개발된 전력설비의 감시진단장치 중 송전선로 감시를 위한 센서 및 센서네트워크를 제주 구좌읍의 스마트그리드 실증단지내 기기설치 설치가 진행중이다. 실증사업 1단계로 SG실증단지의 송전선로를 활용하여 성과물의 성능검증하기 위해 송전선로 감시시스템을 현장에 적용하여 성능을 확인한 실증사례 및 문제점에 대한 개선사항을 소개하고 향후 2단계로 추가 실증 방향 및 송전선로용 센서를 활용한 시스템 운영 전망을 살펴보고자 한다.

• Journal of the Semiconductor & Display Technology
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• v.13 no.1
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• pp.73-81
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• 2014

In this paper, high-speed Hybrid MAC (Medium Access Control layer) implementation suitable for smart grid applications is researched. MB-OFDM (Multi-Band Orthogonal Frequency Division Multiplexing) is considered for high-speed communication method in smart grid application. In this paper, the MAC adopts the distributed network managing method. Also, the MB-OFDM merit of high-speed transfer rate of up to 480Mbps must be supported. Hence, this paper presents an efficient hardware-software integration (co-design) method in order to realize a high- speed transmission, and a realizing method of distribution network. Finally, MAC performance and reliability based on MB-OFDM PHY (PHYsical layer) are confirmed through simulation and emulation.

• Journal of Electrical Engineering and Technology
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• v.12 no.1
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• pp.64-71
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• 2017

Considering the volatility, intermittent and random of photovoltaic (PV) generation systems, accurate forecasting of PV power output is important for the grid scheduling and energy management. In order to improve the accuracy of short-term power forecasting of PV systems, this paper proposes a prediction model based on environmental factors and support vector machine optimized by genetic algorithm (GA-SVM). In order to improve the prediction accuracy of this model, weather conditions are divided into three types, and the gray correlation coefficient algorithm is used to find out a similar day of the predicted day. To avoid parameters optimization into local optima, this paper uses genetic algorithm to optimize SVM parameters. Example verification shows that the prediction accuracy in three types of weather will remain at between 10% -15% and the short-term PV power forecasting model proposed is effective and promising.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.6
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• pp.1255-1260
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• 2011

In this paper, we study on the reliability of Very High-rate Power Line Communication (VH-PLC) for Smart Grid, so that the resultant data rate is over 400Mbps at a physical layer. Firstly, reviewing the research trend of the PLC, we discuss the required techniques for supporting the Smart Grid. Considering a pre-specification with the value of several parameters, we investigate a multi-carrier modulation technique to overcome limitations of higher rate transmission under power line channel environments. Then, we propose a system specification of the VH-PLC in the sense of enhancing two features. One is resolving the problem of the co-existence of the deployed high-speed PLC according to the published standardization of KS X 4600-1 in Korea. The other is getting better performance on the grid adopting the diverse element techniques, such as multi-carrier modulation, a subcarrier utilization mode, a variable rate LDPC (Low Density Parity Check) code, and a time and frequency diversity technique. Further, a simulation tool, composed of an Event-Driven simulator and a Time-Driven simulator, is developed for the purpose of verifying the system performance and continuously cross-checking the test bench signal of the proposed VH-PLC system.

• International Journal of Computer Science & Network Security
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• v.22 no.4
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• pp.1-12
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• 2022

In order to overcome the power fluctuation issues in photovoltaic (PV) smart grid-connected systems and the inverter nonlinearity model problem, an adaptive backstepping command-filter and a double second order generalized Integrators (DSOGI) controller are designed in order to tune the AC current and the DC-link voltage from the DC side. Firstly, we propose to present the filter mathematical model throughout the PV system, at that juncture the backstepping control law is applied in order to control it, Moreover the command filter is bounded to the controller aiming to exclude the backstepping controller differential increase. Additionally, The adaptive law uses Lyapunov stability criterion. Its task is to estimate the uncertain parameters in the smart grid-connected inverter. A DSOGI is added to stabilize the grid currents and eliminate undesirable harmonics meanwhile feeding maximum power generated from PV to the point of common coupling (PCC). Then, guaranteeing a dynamic effective response even under very unbalanced loads and/or intermittent climate changes. Finally, the simulation results will be established using MATLAB/SIMULINK proving that the presented approach can control surely the smart grid-connected system.

• Journal of Satellite, Information and Communications
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• v.7 no.2
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• pp.1-7
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• 2012

In recent years, importance of environmental protection and energy resources has increased. Therefore, eco - friendly consumption patterns is rapidly increased. Accordingly, efficient energy consumption technology is noted in a variety of industries. Smart grid technology can improve energy efficiency by using IT technology. Among them, the demand response is an critical factor in the smart grid. In this paper, we present basic concept of smart grid and demand response. In addition, we present demand response technology and its application examples.

• KEPCO Journal on Electric Power and Energy
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• v.7 no.1
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• pp.101-105
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• 2021

Encouragement of DER from Korean government with several policies boosts DER installation in power system. When the penetration of DER in the grid is getting high, loss of generation with break-away of DER by abnormal grid conditions should be considered, because loss of high generation causes abnormal low frequency and additional operations of protection system. Therefore, KEPCO where is Korean power utility is preparing improvement in regulations for DERs connected to the grid to support abnormal grid conditions such as low and high frequencies or voltages. This is called 'Ride Through' because the requirement is for DER to maintain grid connection during required periods when abnormal grid conditions occur. However, it is not easy to have a test for ride through capability in reality because emulation of abnormal grid conditions is not possible in real power system in operation. Also, it is not easy to have a study on grid effect when ride through capability fails with the same reason. PHILs (Power Hardware In the Loop System) makes it possible to analyze power system and hardware performance at once. Therefore, this paper introduces PHILs test methods and presents verification of ride through capability especially for low voltage grid conditions.

• Journal of Digital Convergence
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• v.11 no.11
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• pp.37-52
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• 2013

Prior to full-scale implementation of smart grid, the Korean government is conducting a smart grid testbed in Jeju island. However, the participants of the ongoing program are skeptical about the success of the expansion of smart grid. The concern rises from various reasons; the limits of the Korean electricity market mainly led by both the government and KEPCO, high stability and reliability of the existing electricity grid, insufficient utilization of renewable energy, and public fear of raised electricity bills. Five key issues in regards to facilitating the Korean smart grid market are extracted and evaluated. The issues are conflict of interest among participants, the effect of introducing real-time pricing, lack of customer participation of demand response, and absence of business models.

• KEPCO Journal on Electric Power and Energy
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• v.3 no.1
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• pp.1-7
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• 2017

The collection and analysis of power information in the smart grid is essential. The collected utilize power information can be used to efficiently utilize power such as power generation and distribution. The role of smart meters communication through wire and wireless cable is important for collecting power information. Recently, many countries around the world are establishing international standards or unique standards of smart meter communication for power information collection of many smart meters. Thus, this paper investigates smart meter related papers and materials, and summarizes international and national standards for smart meter communication.

• Journal of Electrical Engineering and Technology
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• v.7 no.3
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• pp.443-450
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• 2012

As power grids are integrated into one big umbrella (i.e., Smart Grid), communication network plays a key role in reliable and stable operation of power grids. For successful operation of smart grid, interoperability and security issues must be resolved. Security means providing network system integrity, authentication, and confidentiality service. For a cyber-attack to a power grid system, which may jeopardize the national security, vulnerability of communication infrastructure has a serious impact on the power grid network. While security aspects of power grid network have been studied much, security mechanisms are rarely adopted in power gird communication network. For security issues, strict timing requirements are defined in IEC 61850 for mission critical messages (i.e., GOOSE). In this paper, we apply security algorithms (i.e., MD-5, SHA-1, and RSA) and measure their processing time and transmission delay of secured mission critical messages. The results show the algorithms satisfying the timing requirements defined in IEC 61850 and we observer the algorithm that is optimal for secure communication of mission critical messages. Numerical analysis shows that SHA-1 is preferable for secure GOOSE message sending.