A Study on the Miniaturization of a Protective Device for the Micro Smart Grid Simulator

Yun‑Seok Ko,Kyung Ryu,Min‑Soo Oh,Hyuk‑Sik Yoon 대한전기학회 2020 Journal of Electrical Engineering & Technology Vol.15 No.1

In this paper, a miniaturization methodology of protective devices (PDs) was proposed which plays a key role in evaluating the efectiveness of the developed protection and control algorithms in the micro smart grid simulator. The micro PD was designed to have the rated voltage of 19 V and the breaking current of 20 A, and was designed in a multi-layered hardware structure to satisfy the size of 13×13 cm2 . Also, the micro PD was designed in a multifunctional structure to allow one micro PD to perform all the functions of the circuit breaker, recloser and switches on the micro smart grid simulator to enhance the efciency of development. Finally, it was verifed that the developed micro PD can be applied as protective devices of the micro smart grid simulator by showing that it operates correctly according to the predetermined operation sequence for the test scenarios on the built test system.

전문가 시스템의 불확실성 처리 기법 분석에 대한 연구

고윤석 남서울대학교 공학연구센터 2003 공학연구 Vol.4 No.-

Recently, one of the most preferred methods in the field of artificial intelligence is an expert system which can perform the same function as the expert by programming the inference method and experience knowledge of the expert of the applied field. This paper studies the methodology to process the uncertainty occurring in the process of designing the expert systems. First, two methods such as probability theory, Dempster-Shafer method are discussed to search the relative advantage for methods used widely generally. Next, typically MYCIN`s certainty factor method, Prospector`s subjective Bayesian method, and disadvantages of expert systems devised especially to process the uncertainty of applied fields. It is expected that the results of this study can assist to determine and design the methods processing the uncertainty occurring in the process of developing the expert systems for diversity fields.

지식학습능력을 가지는 전압제어 전문가 시스템에 대한 연구

고윤석 남서울대학교 2005 남서울대학교 논문집 Vol.11 No.1

The existing voltage control expert system can not propose the solution in single iteration process for severe voltage problem of the electric power system. In this paper study. an expert system with knowledge learning capability is introduced which can solve quickly and effectively the severe voltage problems. First, the basic configuration procedures of the decision tree is defined, and then TM(Tree Modification) method modifying the decision tree is explained which the modified ID3 learning algorithm. And, an AVCES(Advanced Voltage Control Expert System) with learning capability based on TM method is considered to improve the inefficiency of the existing voltage control expert system. Finally, the application possibility to real power system by simulating the diversity scenarios for the IEEE 30 bus system is verified. Also, It is verified that this TM method is very effective in solving the severe voltage control solution.

심층추론에 기반한 지식학습능력을 가지는 전문가 시스템

고윤석 남서울대학교 2005 남서울대학교 논문집 Vol.11 No.2

The existing expert system based on heuristic rule can not attempt the problem-solving for the events not experienced, so, the spreading effect may be severe. In this paper, an expert system is discussed which learns system operating knowledge from training set in initial time, and modify the incomplete knowledge or generate the new knowledge utilizing the learning capability when a event not experienced occurs. First, the characteristic and configuration is surveyed for the expert system with knowledge learning capability. Next, the diversity inference methods are studied which can applied as the deep inference method of the self-learning expert system based on the deep inference. Finally, inductive learning methods are studied to extract the knowledges from the training set in system initial time.

전문가 시스템의 전력계통 적용 현황 및 개발환경에 대한 고찰

고윤석 남서울대학교 공학연구센터 2002 공학연구 Vol.3 No.-

This paper surveys and analyzes the applications and its fields of expert system to the power system. The development tools and languages of expert system is surveyed, which is required in the process of design and implementation of expert system in the field of electric power system. Basic conditions required to apply development tools of expert system to power system is analyzed and described. It is expected that this study results can be utilized as effective methodology for expert system application.

유비쿼터스 기반 원격 검침 시스템의 조사 및 분석에 대한 연구

고윤석 남서울대학교 2008 남서울대학교 논문집 Vol.14 No.-

This paper aims at determining the remote meter-reading strategy to correspond to the ubiquitous environments. At first, it survey and analysis the present situation of domestic and foreign remote meter-reading system . Next, the advantage and the disadvantage are compared for communication methods between meter-reading device and gateway in home, which include ADSL, PLC, CATV, RF, CDMA and wireless lan etc.. Finally, the CDMA/RF based remote meter-reading system, the CATV/inter-net based remote meter-reading system, the PLC(Power Line Carrier) communication based remote meter-reading system and the optical cable/RF(PLC) based remote meter-reading system are surveyed and analyzed among domestic and overseas remote meter-reading systems. And, it is identified that the optical cable/RF(PLC) based remote meter-reading system among those is very effective at the view points of the economics and easy of installation. Key Words : Ubiquitous System, Remote Meter-Reading System

매트랩을 활용한 차수 줄임형 관측기 설계에 대한 연구

고윤석 남서울대학교 공학연구센터 2001 공학연구 Vol.2 No.-

This paper designs the state vector feedback control system to obtain arbitrary poles using the canonical form when the states of plant is unobservable The functional observer is adopted in order to estimate the unobservable states as the observer of minimum order. The state vector feedback system and the reduced order observer for the linear single input, multiple output are simulated using MATLAB under the 586 PC. Also, it is expected that this design methodology can be applied to linear time-invariant system as well as time-variant, nonlinear system.

이산 프리에 변환(DFT)기법의 배전계통 HIF 해석 적용을 위한 기초기술 연구

고윤석 남서울대학교 2007 남서울대학교 논문집 Vol.13 No.3

ABSTRACT : It is very difficulty to detect the HIF(High Impedance Fault) ofdistribution system is very difficulty because that the current variation isvery little by high impedancefault circuit. And, the spread effect of thefault is very severe including a loss of human lives. Accordingly, in thispaper, the HIF analysis methodology of distribution is studied on thebased on DFT(Discrete Fourier Transformation). At first, the main topicsare analyzed such as the typical distribution configuration, diversityevents and DFT. The basic technology for the detection of HIF ofdistribution system basedon DFT method is analyzed by applying theDFT method to the real measured HIF waveform. Here, the waveform isobtained bygenerating the artificial HIF using an artificial faultequipment.

너비제한 탐색법에 근거한 주변압기 과부하 해소 전략 설계 및 구현

고윤석 남서울대학교 2005 남서울대학교 논문집 Vol.11 No.2

Most of the existing expert system applications to the main transformer overload problem events adopts the best-first search method guided by heuristic as problem-solving strategy. This search method has an advantage which can determine in real-time the control strategy satisfying the operating constraints by minimizing the search space, but has a disadvantage which can not guarantee the optimal solution. Accordingly, this paper proposes the releasing strategy of the main transformer overload based on the breadth-limitation search, which makes it possible to obtain the solution of more improved performance by limiting the search space within the extent of real-time constraints. Finally, the effectiveness and the accuracy of the proposed control strategy are verified by simulation work for the given test distribution system.

배전계통 HIF 해석을 위한 이산 웨이브렛 변환 기법의 적용 기초기술 연구

고윤석 남서울대학교 2007 남서울대학교 논문집 Vol.13 No.3

ABSTRACT : This paper studies the basic technology to apply the DWT(DiscreteWsavelet Transformation) to the HIF problem of distribution system. Incase of the HIF(High Impedance Fault) of distribution system, the variation of feeder current is very little by the high impedance fault circuit. Therefore,to detect the HIF is very difficulty At this time, the spread effect of the fault can be very severe including a loss of human lives. At first, the protection coordination principles of distribution system is reviewed. The basic technology based on DWT method to solve the HIF problem is analyzed by applying the DWT method to the real measured HIF waveform. Here,the real measured waveform is obtainedby generating the artificial HIF using an artificial fault equipment. Finally, the basic application method of the DWT to the HIF is proved by showing the DWT application results to the HIF waveform. Because this paper reviews only the basic methodology for the HIF field, the addition research is required continuously in order to obtain higher fault recognition rate.