• 전기학회논문지
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• 제60권12호
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• pp.2183-2189
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• 2011

Since main portion of the required electric power in Jeju Island is provided from the mainland through two HVDC lines, Jeju HVDC has a most significant impact on Jeju power system. Average wind speed of Jeju Island is the highest among several candidates in South Korea. So, Jeju Island has been a suitable site for the construction of wind farms where several wind farms are now operating and several others to be sited. Since the large-scale wind generation could have adverse impacts on the stable operation of Jeju power system, wind power is also important for the stability of Jeju power system. Therefore, accurate modeling of Jeju HVDC and wind farms is required for stability analysis of Jeju power system. In this paper, PSS/E-based dynamic modeling of Jeju HVDC and DFIG wind farms is proposed. Model-writing technique of PSS/E is used to develop USRAUX model and USRMDL model for controlling the frequency of HVDC and imposing an operation limit of wind power, respectively. Dynamic characteristics of Jeju HVDC and DFIG wind farms are analyzed through the dynamic simulations. The simulation results show the effectiveness of the developed models for Jeju power system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 A
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• pp.292-294
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• 2004

In this paper, we design the GA-fuzzy precompensator of a Power System Stabilizer for Thyristor Controlled Series Capacitor(TCSC-PSS) for enhancement of power system stability. Here a fuzzy precompensator is designed as a fuzzy logic-based precompensation approach for TCSC-PSS. This scheme is easily implemented simply by adding a fuzzy precompensator to an existing TCSC-PSS. And we optimize the fuzzy precompensator with a genetic algorithm for complements the demerit such as the difficulty of the component selection of fuzzy controller, namely, scaling factor, membership Auction and control rules. Simulation results show that the proposed control technique is superior to a conventional PSS in dynamic responses over the wide range of operating conditions and is convinced robustness and reliableness in view of structure.

• 서비스연구
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• 제12권2호
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• pp.94-105
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• 2022

본 연구는 탈산업화 사회의 관점에서 서비스 디자인 및 제품 서비스 시스템(PSS)의 차이점에 대한 이론적 개념을 명확히하고 새롭게 통합된 디자인 전략을 제안하는 것이 주요 목적이다. 서비스 디자인은 기존 서비스를 개선하거나 혁신하고 지속적인 탐색과 반복 과정에서 생가는 문제를 해결하는 사용자 중심 디자인 접근 방식이다. 그러나 PSS는 기업을 위한 혁신적인 비즈니스 전략으로서 고객에게 제품과 서비스의 통합 기능을 제공하고 시스템 프로세스를 최적화함으로써 기업의 경쟁력을 높이는 것이 주요 목적이다. 본 연구는 문헌조사 방법을 통해 서비스 디자인과 PSS의 개념과 연구 현황, 디자인 방법을 정리하였다. 그리고 디자인 진행 과정에서 서비스 디자인과 PSS의 차이점을 비교하여 정리하였다. 본 연구에서 제안하는 최종 내용은 서비스 디자인 개념을 효과적으로 구현하기 위해 사용자 경험을 PSS의 설계 프로세스에 통합하여 시스템화한 프로세스를 사용자의 요구에 맞게 제안하였다.

• 디자인융복합연구
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• 제16권3호
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• pp.69-84
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• 2017

서비스 블루프린트(Service blueprint)는 새로운 서비스 시스템을 제안하는 단계에서 고객을 중심으로 각 서비스 요소 간의 상호작용을 한 눈에 보여 주고 서비스 전체의 흐름을 파악하기 위해 사용되는 것으로서 온라인 비즈니스가 개발되기 전인 1980년대에 제안된 것이다. 그러나 오늘날의 서비스는 제품 서비스 시스템(PSS)으로 확장되거나, 온라인과 오프라인으로 채널이 다양해져, 기존의 서비스 블루프린트는 이를 표현하기에 불충분하다. 이에 본 연구는 각 비즈니스에 최적화된 서비스 블루프린트 유형을 제안하고자 하였다. 이를 위해 연구에 활용될 PSS사례 137개를 수집한 후 비즈니스 매트릭스를 제작하여 사례를 분류하고, 대표사례를 선정하여 총 두 차례의 실험을 진행하였다. 그 결과 매트릭스에 대응하는 6가지의 서비스 블루프린트 유형인 온라인 서비스형, 온라인 원격지원형, 셀프렌탈형, 온라인 주문형, 전통적 유형, 오프라인 지원형을 도출할 수 있었다. 이후 해당 유형의 적합성을 판단하기 위하여 검증을 진행하여 제안한 서비스 블루프린트의 6가지 유형이 적합함을 확인하였다. 이를 통하여 PSS디자인 또는 개발 시 비즈니스의 특성에 맞게 선택적으로 사용할 수 있음을 입증하였고, 향후 본 연구에서 제안하는 서비스 블루프린트의 유형이 클라이언트에게 효과적으로 전달될 수 있는 템플릿이 되길 바라며 서비스 디자이너나 개발자, 기획자와의 커뮤니케이션에도 효과적으로 사용되길 기대한다.

• 전기학회논문지P
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• 제51권2호
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• pp.60-67
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• 2002

This paper presents a control approach for designing a self tuning fuzzy controller for a synchronous generator excitation and SVC system. A combination of thyristor-controlled reactors and fixed capacitors (TCR-FC) type SVC is recognized as having the most flexible control and high speed response, which has been widely utilized in power systems, is considered and designed to improve the response of a synchronous generator, as well as controlling the system voltage. The proposed parameter self tuning algorithm of fuzzy controller is based on the steepest decent method using two direction vectors which make error between inference values of fuzzy controller and output values of the specially selected PSS reduce steepestly. Using input-output data pair obtained from PSS, the parameters in antecedent part and in consequent part of fuzzy inference rules are learned and tuned automatically using the proposed steepest decent method. The related simulation results show that the proposed fuzzy controller is more powerful than the conventional ones.

• 대한전기학회논문지:전력기술부문A
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• 제50권7호
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• pp.324-332
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• 2001

In this paper, it is suggested that the selection method of parameter of Power System Stabilizer(PSS) with robustness in low frequency oscillation for Static VAR Compensator(SVC) using a Real Variable Elitism Genetic Algorithm(RVEGA). A SVC, one of the Flexible AC Transmission System(FACTS), constructed by a fixed capacitor(FC) and a thyristor controlled reactor(TCR), is designed and implemented to improve the damping of a synchronous generator, as well as controlling the system voltage. The proposed PSS parameters are optimized using RVEGA in order to maintain optimal operation of generator under the various operating conditions. To decrease the computational time, real variable string is adopted. To verify the robustness of the proposed method, we considered the dynamic response of generator speed deviation and generator terminal voltage by applying a power fluctuation and three-phase fault at heavy load, normal load and light load. Thus, we prove the usefulness of proposed method to improve the stability of single machine-infinite bus with SVC system.

• 산업경영시스템학회지
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• 제40권3호
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• pp.27-37
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• 2017

As the global uncertainty of manufacturing has increased and the quality problem has become global, the recall has become a fatal risk that determines the durability of the company. In addition, as the convergence of PSS (product-service system) product becomes common due to the development of IT convergence technology, if the function of any part of hardware or software does not operate normally, there will be a problem in the entire function of PSS product. In order to manage the quality of such PSS products in a stable manner, a new approaches is needed to analyze and manage the hardware and software parts at the same time. However, the Fishbone diagram, FTA, and FMEA, which are widely used to interpret the current quality problem, are not suitable for analyzing the quality problem by considering the hardware and software at the same time. In this paper, a quality risk assessment model combining FTA and FMEA based on defect rate to be assessed daily on site to manage quality and fishbone diagram used in group activity to solve defective problem. The proposed FTA-FMEA based risk assessment model considers the system structure characteristics of the defect factors in terms of the relationship between hardware and software, and further recognizes and manages them as risk. In order to evaluate the proposed model, we applied the functions of ITS (intelligent transportation system). It is expected that the proposed model will be more effective in assessing quality risks of PSS products because it evaluates the structural characteristics of products and causes of defects considering hardware and software together.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1990년도 추계학술대회 논문집 학회본부
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• pp.227-230
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• 1990

In this paper we present a variable structure systeme-model following adaptive control (VSS-MFAC) method for an uncertain turbo-generator system which is apt to suffer from the unmodeled parameter uncertainties and the external disturbances. The simulation results for the power system stabilizer(PSS) exhibit robust adaptive model-following properties well in the PSS designed by the proposed VSS-MFAC methodology when a step change in the mechanical torque and a parameter variation is applied.

• 전기학회논문지
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• 제63권7호
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• pp.883-888
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• 2014

The paper describes the parameter tuning of power system stabilizer (PSS) for a power plant based on hybrid system modeling. The existing tuning method based on bode plot and root locus is well applied to keep power system stable. However, due to linearization of power system and an assumption that the parameter ratio of the lead-lag compensator in PSS is fixed, the results cannot guarantee the optimal performances to damp out low-frequency oscillation. Therefore, in this paper, hybrid system modeling, which has a DAIS (differential-algebraic-impusive-switched) structure, is applied to conduct nonlinear modeling for power system and find optimal parameter set of the PSS. The performances of the proposed method are carried out by time domain simulation with a single machine connected to infinite bus (SMIB) system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 춘계학술대회 논문집 전력기술부문
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• pp.14-16
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• 2001

The Eigen-Sensitivity theory at full system is used to supplement drawback of the existing PSS gain tuning methods in this paper. Hessenberg method is used to linear analysis. This proposed method is successfully tested on KEPCO 2003 off-peak power system to improve local mode. The designed PSS at 2003 off-peak system is installed in 2003 peak system to improve robustness.