• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1992년도 춘계학술대회 논문집
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• pp.374-379
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• 1992

The automation system oriented as one of the second year automation projects for the small and medium sized enterprises(SME) was developed for the improvement of the production rate and cut the required manpower in the field of the relay which is one of the small electric components used in various industrial fields. The objectives of this study are not only improving the international competition of the relay itself but also partially solving the technical and financial porblems featured by common bottlenecks of the SME for effecient assembly automation. For the purpose of these objectives, several topics are studied as followings. -. Analyzing the adjustment process and determining the specification of the automation system. -. Determining the layout for the automation system to meet the determined specification. -. Detail design ofthe automation system for relay adjusment and inspection. -. Control system design. -. Automation system development and performance test.

• 한국컴퓨터정보학회논문지
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• 제12권3호
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• pp.267-275
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• 2007

이 논문에서는 터미널 부분의 중요 신호를 유무선 방식을 통하여 통합적으로 감시, 관리하기 위한 DCS 터미널 원격 감시 시스템을 설계 및 구현한다. 시스템은 터미널 부분의 릴레이들의 동작 상태 및 퓨즈의 이상 유무를 실시간으로 감시하기 위한 보드와 각 릴레이들의 동작 상태를 실시간으로 확인이 가능하며 에러 발생 시 에러 유형을 즉시 제공하며 릴레이의 규격 및 사용기간을 고려하여 교체시기를 알려주어 DCS 터미널 원격 감시 미들웨어로 구성된다. 이 시스템은 릴레이의 고장을 쉽게 진단할 뿐만 아니라 사전에 예방함으로써 산업분야의 경제적인 효과가 기대된다.

• Journal of Power Electronics
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• 제11권6호
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• pp.890-896
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• 2011

In this paper the impact of a SSSC and a STATCOM on the impedance calculated by a distance relay is investigated. Both analytical analysis and simulations are provided. The STATCOM/SSSC control systems are modeled in detail. It is demonstrated that a SSSC has a greater impact on the calculated impedance by an A-G distance relay element. Several scenarios are considered in the simulations like the impact of the fault conditions, the compensator settings, the power system conditions and so on. All the simulations are carried out in MATLAB/Simulink with detailed models of the SSSC and the STATCOM.

• 조명전기설비학회논문지
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• 제28권7호
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• pp.34-40
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• 2014

In this paper, we want to know the optimal replacement cycle(time) for this study was performed. The optimal preventive replacement age can be fond by finding the value of time that minimizes the cost function(model of Barlow and Jardine). In addition, The reliability of the relay according to the service environment were studied. The use of the exchange relay period is longer, and maintenance cost rate(per hour) may increase, and also the reliability may cause a decline. In addition, considering the preventive maintenance and purchase order, a representative relay(RAX-L440-A type) life was calculated.

• 전기저널
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• 9호통권10호
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• pp.11-14
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• 1976

• 대한전기학회논문지:전력기술부문A
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• 제49권10호
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• pp.516-523
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• 2000

In this paper, intelligent methods using digital protective relay in power supervisory control system is developed in order to protect power systems by means of timely fault detection and diagnosis during operation for induction motor which has various load environments and capacities in power systems. The spectrum pattern of input currents was used to monitor to state of induction motors, and by clustering the spectrum pattern of input currents, the newly occurrence of spectrums pattern caused by faults were detected. For diagnosis of the fault detected, the fuzzy fault tree was derived, and the fuzzy relation equation representing the relation between an induction motor fault and each fault type, was solved. The solution of the fuzzy relation equation shows the possibility of each fault's occurring. The results obtained are summarized as follows: 1) The test result on the basis of KEMC1120 and IEC60255, show that the operation time error of the digital motor protective relay is improved within ${\pm}5%$. 2) Using clustering algorithm by unsupervisory learning, an on-line fault detection method, not affected by the characteristics of loads and rates, was implemented, and the degree of dependency by experts during fault detection was reduced. 3) With the fuzzy fault tree, fault diagnosis process became systematic and expandable to the whole system, and the diagnosis for sub-systems can be made as an object-oriented module.

• 제어로봇시스템학회논문지
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• 제2권4호
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• pp.318-323
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• 1996

The speed of SR(Switched Reluctance) motor can be controlled by switching angle. However, since the relation between speed and switching is nonlinear, it is difficult for simple adjustment schemes to achieve the desired performances. In this paper, an error.feedback nonlinear compensator with robustness is proposed for improving the performances of the switching angle controlled SR motor. The proposed controller consists of integral type control and relay type control. The integral type controller which operates regulation, is derived by the steady.state I/O(input/output) map and the relay type controller which works tracking, is designed by Lyapunov stability theory. The validities of the proposed controller are confirmed with the experimental results.

• 전기학회논문지P
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• 제62권3호
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• pp.133-138
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• 2013

A large generator is an important role in transferring an electric power to power system. The IEDs of large generator often use microprocessor technology to obtain a digital relay system with a wide range of measuring, protection, control, monitoring, and communication functions. However, all generator protection and control systems in Korea imported from abroad and are being operated. In order to reduce the large expense and improve the reliable operation, development of generator protection and control system by domestic technology is required. This paper deals with the design of the IED of generator protection panel for development of generator protection and control system. The major emphasis of the paper will be on the description of hardware and signal processing test results and measurement accuracy of the prototype IED. By developing of generator IED based on DSP and microprocessor, replacement of the generator protection panel imports are expected to be effective.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1994년도 Proceedings of the Korea Automatic Control Conference, 9th (KACC) ; Taejeon, Korea; 17-20 Oct. 1994
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• pp.257-262
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• 1994

This paper describes an autotuning fuzzy PID controller for a position control of DC serve motor. Because ZNM(Ziegler-Nichols Method) with relay feedback has the difficulty in re-tuning the PID parameters and adaptive method has complex algorithm, a new method to overcome those problems is required. The proposed scheme determines the initial PID gains by using ZNM with relay feedback, and then re-tunes the optimal PID parameters by using fuzzy expert system whenever control conditions are changed. To show the validity of the proposed method, a position control of DC servo motor is illustrated by computer simulation and is experimented by a designed controller.

• 대한전자공학회논문지
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• 제22권3호
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• pp.31-42
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• 1985

DC motor를 제어하기 위하여, 두개의 feedback sensor 즉, potenfiometer와 tachometer를 사용하고 있다. 최적 제어치를 얻기위한 제어 방법으로써 선형계로써는 kalman regular type, 비 선형계로써는 on-off relay-type와 상태 제환을 적용하였다. 역시, 추적각의 측정 방법으로서는. 측정치를 이웅한 위치와 속도 미분치를 이용한 위치와 속도, 그리고 관측기를 이용한 위치, 속도와 오제곱 분산치를 추정하여 추적각의 제어치를 비교 분석하였다.