• Journal of Power Electronics
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• 제14권3호
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• pp.608-620
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• 2014

In this paper, an adaptive neural phase-locked loop (AN-PLL) based on adaptive linear neuron is proposed for grid-connected doubly fed induction generator (DFIG) synchronization. The proposed AN-PLL architecture comprises three stages, namely, the frequency of polluted and distorted grid voltages is tracked online; the grid voltages are filtered, and the voltage vector amplitude is detected; the phase angle is estimated. First, the AN-PLL architecture is implemented and applied to a real three-phase power supply. Thereafter, the performances and robustness of the new AN-PLL under voltage sag and two-phase faults are compared with those of conventional PLL. Finally, an application of the suggested AN-PLL in the grid-connected DFIG-decoupled control strategy is conducted. Experimental results prove the good performances of the new AN-PLL in grid-connected DFIG synchronization.

• Journal of Satellite, Information and Communications
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• 제8권2호
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• pp.50-55
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• 2013

The smart grid is a next-generation power grid to create a new value-added information technology. Power providers and consumers exchange information in real-time bi-directional, and optimize energy efficiency with using the smart grid. This paper describes the concept of demand response of the communication system used in the protocol communication model of the smart grid.

• Journal of Electrical Engineering and Technology
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• 제9권3호
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• pp.1072-1079
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• 2014

This paper introduces a coordinated droop control for the stand-alone DC micro-grid, which is composed of photo-voltaic generator, wind power generator, engine generator, and battery storage with SOC (state of charge) management system. The operation of stand-alone DC micro-grid with the coordinated droop control was analyzed with computer simulation. Based on simulation results, a hardware simulator was built and tested to analyze the performance of proposed system. The developed simulation model and hardware simulator can be utilized to design the actual stand-alone DC micro-grid and to analyze its performance. The coordinated droop control can improve the reliability and efficiency of the stand-alone DC micro-grid.

• 한국정보통신설비학회:학술대회논문집
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• 한국정보통신설비학회 2008년도 정보통신설비 학술대회
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• pp.473-477
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• 2008

In this paper, we introduce the positioning methods using the grid sensor network. The basic operational principle of grid sensor network can be the wireless communication using the sensor node attached on the objects. Sink node receives the environmental information (e.g., temperature, humidity and so on), and transmits the information to the core database. Since the grid sensor network basically uses wireless communication, it is necessary to observe the place where grid sensor nodes to be installed. In this sense, we carried out the practical measurement on the wireless propagation in an applicable field. In addition, link budget study and SNR estimation works were done in accordance with the results from the measurement.

• Proceedings of the KIPE Conference
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• 전력전자학회 2014년도 전력전자학술대회 논문집
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• pp.213-214
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• 2014

This paper compares two instantaneous reactive power definitions in DFIG wind turbine with a back-to-back three-level neutral-point clamped voltage source converter under unbalanced grid conditions. In general, conventional definition of instantaneous reactive power is obtained by taking an imaginary component of complex power. The other definition of instantaneous reactive power can be developed based on a set of voltages lagging the grid input voltages by 90 degree. A complex quantity referred as a quadrature complex power is defined. Proposed definition of instantaneous reactive power is derived by taking a real component of quadrature complex power. The characteristics of two instantaneous reactive power definitions are compared using the ripple-free stator active power control algorithm in DFIG. Instantaneous reactive power definition based on quadrature complex power has a simpler current reference calculation control block. Ripple of instantaneous active and reactive power has the same magnitude unlike in conventional definition under grid unbalance. Comparison results of two instantaneous reactive power definitions are verified through simulation.

• The Transactions of The Korean Institute of Electrical Engineers
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• 제58권11호
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• pp.2175-2184
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• 2009

This paper describes operational analysis results of the DC micro-grid using detailed model of distributed generation. Detailed model of wind power generation, photo-voltaic generation, fuel-cell generation was implemented with the user-defined model of PSCAD/EMTDC software that is coded with C-language. The operation analysis was carried out using PSCAD/EMTDC software, in which the power circuit is implemented by built-in model and the controller is modelled by user-defined model that is also coded with C-language. Various simulation results confirm that the DC micro-grid can operate without any problem in both the interconnected mode and the islanded mode. The operation analysis result confirms that the DC micro-grid make it feasible to provide power to the load stably. And it can be utilize to develop the actual system design and building.

• Journal of the Korea Academia-Industrial cooperation Society
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• 제10권9호
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• pp.2350-2353
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• 2009

For applications that are grid enabled, the grid can offer a resource balancing effect by scheduling grid jobs on machines with low utilization. When jobs communicate with each other, the internet, with storage resources, an advanced scheduler could schedule them to minimize communications traffic or minimize the distance of the communications. We propose an load redistribution algorithm to minimize communication traffic and distance of the communication using genetic algorithm. The experiments show the proposed load redistribution algorithm performs efficiently in the variance of load in grid environments.

• Proceedings of the Korean Information Science Society Conference
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• 한국정보과학회 2002년도 가을 학술발표논문집 Vol.29 No.2 (1)
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• pp.367-369
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• 2002

본 논문은 GRID 상에서 HLA(High Level Architecture)를 기반으로 한 분산 객체 지향 wargame simulation의 디자인과 구현에 관해 기술한다. HLA는 DIS[1]의 뒤를 이어 제안된 아키텍처로서 simulation에 원활한 data교류와 동기화를 제공한다. 또한, GRID는 전세계에 펼쳐져 있는 자원들에 대한 관리와 접근, 사용을 위한 다양한 기능과 안전하고 편리한 security를 보장한다. 본 논문에서는 HLA를 사용해서 simulation에 튀어난 상호 연동 능력과 재사용성을 부여하고, GRID를 통해 대규모의 프로젝트를 위한 광범위한 자원을 보다 안전하고 효율적으로 사용할 수 있도록 하는 환경을 구현하였다. 우리는 이 simulation을 HDOWS-G(HLA-based Distributed Object-oriented War game Simulation on Grid)라 부르기로 한다.

• Journal of Information Technology Services
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• 제7권4호
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• pp.167-178
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• 2008

This paper addresses the issue of workflow on Grid and P2P, and proposes a layered workflow architecture and its related workflow models that are used for not only distributing workflows' information onto Grid or P2P resources but also scheduling the enactment of workflows. Especially, the most critical rationale of this paper is on the fact that the nature of Grid computing environment is fitted very well into building a platform for the maximally parallel and very large scale workflows that are frequently found in very large scale enterprises. The layered architecture proposed in this paper, which we call Enterprise Workflow Grid Architecture, is targeting on maximizing the usability of computing facilities in the enterprise as well as the scalability of its underlined workflow management system in coping with massively parallel and very large scale workflow applications.

• Proceedings of the Korean Society of Computer Information Conference
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• 한국컴퓨터정보학회 2011년도 제44차 하계학술발표논문집 19권2호
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• pp.217-219
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• 2011

Smart Grid를 위해서 전기의 끊김없는 공급과 안전한 전기사용이 중요하다. Smart Grid에 사용되는 전기IT기기의 성능평가와 인증을 받기 위해서는 모듈 기준값, 모듈 성능값, 제품별 기능, 실험장비, 허용오차 등 실험 DataBase가 발생한다. 전기IT기기는, 기존의 존기기기에 IT와 통신기능을 융합하여 전기의 공급과 안전성을 강화시킨 제품이다. 본 논문에서는 Smart Grid DataBase 개발을 위한 전기IT기기들을 안전하게 관리하고, IT와 통신을 통한 인터넷 웹브라우저에서 접속할 수 있는 Java Servlet 기술을 이용한, 전기IT기기에 대한 평가기관 및 인증기관이 실시간으로 평가와 인증 자료를 관리 할 수 있도록 한다.