• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2013년도 춘계학술대회 논문집
• /
• pp.1625-1626
• /
• 2013

• 대한전기학회논문지:전기물성ㆍ응용부문C
• /
• 제53권3호
• /
• pp.168-174
• /
• 2004

On-line monitoring system(OMS) has been developed for the pumped storage generator/motor The OMS is applied to diagnosis of the PD(partial discharge) activity of stator insulation, the shorted-turn of rotor winding and the variation of the air-gap between stator and rotor. The OMS consists of DAS(data acquisition system), main server system, gateway and display PC. The DAS measures the PD, the shorted-turn and air-gap from three sensors installed on the generator/motor. The gateway controls the data which sent by DAS. The main server system saves the data, analyzes the data and conducts the diagnostic algorithm. The display PC shows the diagnostic results of partial discharge, shorted-turn and air-gap. Field tests were conducted using PDA(partial discharge analyzer). The results of the OMS and PDA measurements can be directly correlated with normalized quantity number(NQN), PD magnitude(Qm) and PD pattern.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2000년도 하계학술대회 논문집 C
• /
• pp.1846-1849
• /
• 2000

Off-line and on-line partial discharges were measured on a 828MVA, 22kV and direct hydrogen-cooled large turbine generator. Partial discharge tests were conducted using digital partial discharge detector(PDD) and turbine generator analyzer(TGA). PDD and TGA showed that off-line partial discharge pattern seems to be very, similar to that found with on-line. Most of the partial discharge is originating with the stator slot in the three phases. As the partial discharge activity is very low, the stator insulation condition of this generator is very good.

• 전기학회논문지P
• /
• 제58권4호
• /
• pp.397-403
• /
• 2009

In this paper, an exciter current control of a synchronous generator for ships using a compound type digital automatic voltage regulator (DVAR) in order to provide a constant output voltage of the generator is presented. The compound type DAVR is composed of a controller part to adjust output voltage and an power source unit to supply power to the exciter. The controller part, which generates the PWM switching pattern via the PI controller, drives a power MOSFET for bypass to limit the SG's exciter current. The power source unit part is parallel connected to an output terminal of the generator through a reactor and a power CT. The residual magnetic flux of SG provides exciter current to the exciter through the reactor during the initial running or no load state and load current supplies field current to the exciter through the power CT during loading state. This paper confirmed an experiment to verify the validity of compound type DAVR system for controlling output voltage of synchronous generator.

• 대한전기학회논문지:전기물성ㆍ응용부문C
• /
• 제48권3호
• /
• pp.192-199
• /
• 1999

During start up and shut down, the generator is rotating at a low speed and copper dusts cause arcing between the turns in the slot. Shorted turns occurred primarily by the movement of these copper dusts between individual windings in the generator rotor. Detection of shorted turns was performed in five gas turbine generators in two combined cycle power plants. Two types of permanent and temporary flux probes were used in this paper. These flux probes have been used to develop a methodology for detecting shorted turns in an operating generator's rotor. The flux probes sense the rotor winding slot leakage flux and produce a voltage proportional to the rate of change of the flux. This pattern of flux variation is the signature unique to each rotor winding. An appropriate waveform analysis technique canidentify the pole location, the slot number, and the number of shorted turns within each slot. Shorted turns in field winding of gas turbine generator(125.7 MVA) were detected to twelve turns on al total 190 turns.

• 대한전기학회논문지:전력기술부문A
• /
• 제51권1호
• /
• pp.23-28
• /
• 2002

In order to survey the radiation characteristics of pure line noise of unwanted noise from overhead high voltage AC transmission lines, a disk type gap noise generator was manufactured. Disk size which decides capacitance between the noise generator and earth was selected through preliminary indoor experiments and analysis by using surface charge method. The capacitance is one of principal parameters related to the injection of a proper noise current into lines. On the basis of the capacitance obtained from calculation, 5mm of space was given to the gap of the noise generator to be installed o test line and an aluminum disk of 60cm radius was made. The field experiments were performed with the noise generator hung on the Kochang 765 kV full scale test line. As the results, the useful data which can be used to analysis the radiation characteristics of noise from transmission lines were obtained. Those are the directivity of antenna toward the line, lateral profiles, frequency spectra, height pattern and so on.

• 한국정보과학회논문지:컴퓨팅의 실제 및 레터
• /
• 제6권4호
• /
• pp.393-402
• /
• 2000

UML은 OMG에 의해서 표준 객체지향 모델링 언어로 승인 받았다. 그러나, UML을 지원하는 몇몇의 CASE 도구들이 생성한 C++ 코드는 1대 n 관계나 aggregation 관계의 의미를 정확히 반영하지 못하고 있다. 또한, 상용 CASE 도구들이 하나의 UML 클래스 다이어그램에서 너무 많은 프로그래밍 언어를 지원하기 때문에, 그들은 C++언어가 가지는 특징을 효율적으로 지원하지 못하고 있다. 제안된 C++코드 생성기는 1대 n의 관계, aggregation 관계, 코드 패턴(code pattern), 디자인 패턴(design pattern)을 지원한다.본 논문에서는 UML 클래스 다이어그램 기반의 효율적인 C++ 코드 생성기의 설계와 구현에 대하여 기술한다.

• 컴퓨터교육학회논문지
• /
• 제10권3호
• /
• pp.67-73
• /
• 2007

본 논문에서는 대화 인터페이스 시스템을 구성하는 필수 요소들을 알아보고, 각각에 대한 실용적인 구현 방법을 제안한다. 구현 시스템은 담화 관리자, 의도 분석기, 개체명 인식기, SQL 질의어 생성기, 응답 생성기로 구성된다. 구현 과정에서 비교적 영역 의존성이 낮은 의도 분석 모듈은 통계 기반의 최대 엔트로피 모델을 이용한다. 그리고 높은 영역 이식성을 필요로 하는 개체명 인식기, SQL 질의어 생성기, 응답 생성기는 단순 패턴 매칭 방법을 이용한다. 일정 관리 영역에서의 실험에서 구현 시스템은 88.1%의 의도 분석 정확률과 83.4%의 SQL 질의어 생성 성공률을 보였다.

• 한국응용과학기술학회지
• /
• 제27권4호
• /
• pp.415-420
• /
• 2010

This study is focused on the channel design of bipolar plate in the electrode of hydrogen gas generator. The characteristics of hydrogen gas generation was studied in view of efficiency of hydrogen gas generation rate and a tendency of gas flow through the riv design of electrode. Since the flow rate and flow pattern of generated gas in the two phase flow system are the most crucial in determining the efficiency of hydrogen gas generator, we adopted the commercial analytical program of COMSOL MultiphysicsTM to calculate the theoretical flow rate of hydrogen gas from the outlet of gas generator and flow pattern of two phase fluid in the electrode. In this study, liquid electrolyte flows into the bipolar plate and decomposed into gas phase, two phase flow simulation is applied to measure the efficiency of hydrogen gas generation.

• 정보보호학회논문지
• /
• 제11권1호
• /
• pp.3-12
• /
• 2001

본 논문은 무선채널에서 안전한 암호통신을 위해 동기식 스트림 암호시스템을 설계하였다 페이딩 채널에서 설계된 스트립 암호를 통해 암호문을 전송할 때 한 주기 동안 발생하는 동기패턴, 세션키, 암호문 정보에 적합한 인터리빙 기 법을 설계하여 전송함으로써 버스트 오류로부터 암호문을 보호하고 전송성능을 개선하여 robust한 암호통신을 가능하도록 하였다. 본 논문에서는 동적인 인터리빙 depth를 갖는 DAA를 적용함으로써 정적인 인터리빙 depth를 갖는 SAA (static allocation algorithm)보다 전송성능 개선을 얻었다.