• 한국신재생에너지학회:학술대회논문집
• /
• 2008.05a
• /
• pp.21-24
• /
• 2008

Proton Exchange Membrane Fuel Cell (PEMFC) is an attractive candidate for residential power generator due to fast start-up and stop, high efficiency, low emission, and high power density. In this study, we employ short module stack to understand the performance of the unit cell of the stack in terms of operating temperatures. To simulate the practical fuel cell stack of residential power generator, the structure and active area of the short module stack is kept the same as that of the practical fuel cell. The results shows that the electric potential of short module stack is different from the number of cells times the potential of unit cell because of cell-to-cell variation.

• Proceedings of the KIEE Conference
• /
• 2011.07a
• /
• pp.800-801
• /
• 2011

This paper proposes a grid-connected to rotor type doubly fed induction generator (DFIG) in which the rotor winding is connected to the grid instead of the stator winding. The stator size and weight of the proposed grid-connected to rotor type DFIG can be reduced because the proposed type can use rotor core more efficiently compared to the stator type DFIG. In order to verify the size and weight reduction of the proposed type, the loading distribution method (LDM) is utilized. As a design result, the stator outer diameter and weight of the proposed type were decreased. The equivalent circuit analysis and finite element method also performed to verify the design results and to analyze characteristics of the novel DFIG.

• Proceedings of the KIEE Conference
• /
• 2011.07a
• /
• pp.1830-1831
• /
• 2011

최근 스마트폰 등의 산업에서와 같이 발전플랜트에서도 가치창출의 중심이 하드웨어 제조 관리 기술에서 최적 제어 운용의 소프트웨어로 급속히 이동하고 있다. 국내외 발전사 및 관련 연구기관들은 발전플랜트 운용최적화를 위한 다양한 제어, 감시, 분석, 설계, 시뮬레이션, 자원관리 등의 다양한 분야에서 독립적인 소프트웨어 개발을 활발히 수행하고 있으나, 이들 간의 데이터, 이벤트 통신 및 서비스 연동은 미흡한 실정이다. 본 연구에서는 발전플랜트 관련 소프트웨어의 서비스 통합 기반을 마련하고, 안정성 재사용성 이식성 등의 품질을 제고하며 개발자가 쉽고 빠르게 소프트웨어를 구현할 수 있는 발전플랜트 소프트웨어 플랫폼을 제안한다. 이는 화력, 원자력 등의 중대형 발전플랜트 뿐만 아니라 점점 확대되고 있는 태양광, 태양열, 풍력 등 크고 작은 다양한 신재생에너지 발전기에 적용가능하며 발전 효율 및 안정성 향상과 발전플랜트 소프트웨어 산업의 활발한 생태계 조성에 기여할 것으로 기대된다.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.60 no.8
• /
• pp.1555-1559
• /
• 2011

Turbine generator(13.8 kV, 137.5 MW) has high bearing vibration at rotation speed. Shorted turns in generator rotor windings have strong correlation with increased field current which is thus related to increase in bearing vibration. The recurrent surge oscillograph (RSO) test is performed on the rotor winding in turbine generator to detect shorted turns. The result of the RSO test indicates that shorted turns of rotor winding are generated in two locations. The RSO test was capable of identifying the presence, number, and location of shorted turns in generator rotor windings.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.58 no.7
• /
• pp.1375-1379
• /
• 2009

Insulation tests have been performed on two generator stator bars under accelerated aging under a laboratory environment. Electrical stress was applied to stator bar No.1, and electrical and thermal stresses were applied to stator bar No.2. Nondestructive stator insulation tests including the ac current, dissipation factor($tan{\delta}$), and partial discharge tests have been performed on both bars as the bars were aged for 11460 hours. Experimental test results show that ${\Delta}I$, ${\Delta}tan{\delta}$, and partial discharge of No. 1 and No.2 stator bars increased with increased in aging time. It has been concluded from the test that the stator insulation of the two generators are in good condition.

• Journal of the Korean Society of Safety
• /
• v.14 no.4
• /
• pp.100-107
• /
• 1999

The purpose of the study is to investigate the effect of H$_2$ pressure on partial discharge (PD) activity and aging rate in turbine generator winding insulations. A series of field tests and laboratory tests were peformed to investigate the effect of $H_2$ pressure on PD activity. Field tests were conducted at two unit turbine generators in two conditions, in $H_2$ pressure and in air atmosphere. Obtained results are as follows ; 1) ${\Delta}tan{\delta}$ and maximum partial discharge are reduced with increase of $H_2$ pressure and partial discharge inception voltage. 2) The reduction ratio of ${\Delta}tan{\delta}$ due to $H_2$ pressure is higher than one of PD magnitude. 3) Partial discharge pulses suffer from attenuation and distortion when transmitted along windings, because of the complex L-C network between windings. From the result, partial discharge pulses are subjected to resonance phenomena in a generator winding.

• Proceedings of the KIPE Conference
• /
• 2009.11a
• /
• pp.200-202
• /
• 2009

본 논문은 계통전압 불평형시 이중여자 유도형 풍력발전기 (Doubly Fed Induction Generator-DFIG)의 토크 리플 저감과 dc-link 전압의 맥동을 제거하는 기법을 제안한다. 계통전압 불평형 시 DFIG의 동적 모델링을 통해 토크 맥동 성분과 dc-link 전압 리플 성분을 수식화 한다. 유도된 수식을 기반으로 회전자 측 컨버터는 정상분과 역상분을 독립적으로 제어하는 듀얼 전류 제어기를 통해 토크 리플을 저감하며, 계통 측컨버터는 전력이론을 통해 계산된 보상 전류 지령치를 통해 cd-link 전압 맥동을 제거한다. 3kW급 풍력 발전 시스템에 제안하는 기법을 적용한 시뮬레이션 결과를 통해 타당성을 입증한다.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.59 no.8
• /
• pp.1423-1428
• /
• 2010

The results of off-line and on-line diagnostic tests performed on the stator winding of an air-cooled gas turbine(G/T) generator are reported in this paper. Off-line diagnostic tests included measurements of the ac current, dissipation factor(tan${\delta}$), and partial discharge(PD). Six epoxy-mica capacitors were installed in the three phases of G/T generator for performing on-line diagnostic testing with the turbine generator analyzer(TGA). The TGA showed that the normalized quantity number(NQN) and the PD magnitude($Q_m$) were high in phase A of the stator winding. Internal discharges were generated in phases B and C, and slot discharge occurred in phase A. According to the trend analyses of the NQN and $Q_m$ values available for insulation condition assessment for G/T generator stator windings, it was concluded that phases B and C were in good condition, whereas phase A has been significantly deteriorated.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.60 no.10
• /
• pp.1972-1977
• /
• 2011

The mechanical integrity of generator stator windings is one of the critical point because the electric power is generated and conducted to power system through these windings. To cool down the heat emitted from generator winding during its operation, a majority of generators use de-mineralized water characterized by high cooling efficiency. Contrary to such the excellent cooling efficiency, however, the damaged bar insulations attributed to the absorption of cooling water in the generator stator winding lead to highly time- and cost consuming efforts as well as to service deterioration due to unexpected forced outage of generator. It is described that the new design of water absorption sensor using cross capacitance for generator in power plant in order to increase the reliability of water absorption diagnostics for generator stator bar insulation.

• Proceedings of the KIEE Conference
• /
• 2009.07a
• /
• pp.2027_2028
• /
• 2009

본 연구에서는 한국수자원공사 고압회전기 고정자권선 절연체의 진단데이터에 대한 통계적 분석연구에 관하여 설명하고 있다. 10년 이상 수집된 진단데이터를 사용하여 와이블 함수를 이용한 누적확률을 구하였으며, 그 결과로부터 각 진단항목에 대하여 형상모수와 절연상태를 판정하는 진단기준치를 제시하였다. 그 결과로 수력발전기의 대지간 전압에 대한 부분방전량의 기준값으로 10,000pC이하를 제시하였다.