• The Transactions of the Korean Institute of Electrical Engineers C
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• v.55 no.4
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• pp.189-198
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• 2006

In order to improve the reliability of stator windings for hydro generators, it is necessary to detect the defective point and life assessment of the high voltage windings. Especially the on-line partial discharge (PD) test provides the ability to monitor effects, such as slot discharge, internal discharge, and end-winding discharge without interrupting generators, this method has been proven the major testing technology in high voltage rotating machines nowadays. The purpose of this paper is to describe the method of the on-line PD measurement on stator windings for hydro-generator with 13 [kV] class ceramic coupler (CC), on-line PD measuring system, terminal box, and index parameters. Also, the developed PD measuring system and 13 [kV] class CC were installed Daechung-dam generator #2. It was found that this installed sensor and system had good electrical characteristics to detect PD activity during the operating condition with its detection frequency band is between several and several tens MHz.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.533-538
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• 2014

Power generator is one of the most important component of electricity generation system to convert mechanical energy to electrical energy. I t designed robustly to maintain high system reliability during operation time. But unexpected failure of the power generator could happen and it cause huge amount of economic and social loss. To keep it from unexpected failure, health prognostics should be carried out In this research, We developed a health prognostic method of stator windings in power generator with statistical data analysis and degradation modeling against water absorption. We divided whole 42 windings into two groups, absorption suspected group and normal group. We built a degradation model of absorption suspected winding using Fick's second law to predict upcoming absorption data. Through the analysis of data of normal group, we could figure out the distribution of data of normal windings. After that, we can properly predict absorption data of normal windings. With data prediction of two groups, we derived upcoming Directional Mahalanobis Distance (DMD) of absorption suspected winding and time vs DMD curve. Finally we drew the probability distribution of Remaining Useful Life of absorption suspected windings.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.527-532
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• 2014

Generator is the main equipment of a power plant that generates electric power. The line frequency is 60Hz, since that is operated at 3600rpm in fossil power plant. Therefore, the specific frequency 120Hz by the electromagnetic excitation force is generated inherently. If the looseness of stator at generator happens, abnormal sound that has 120Hz and the harmonic frequency is emitted from generator frame. In that case, binding of end-winding or re-wedging is needed for the reduction of sound level. In case of severe level of sound, belly band can be additionally installed at core. In this paper, the characteristics of generator sound is described and modal data is analyzed after installation of belly band.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.1029-1033
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• 2006

During operation of generator, the excitation force with 120Hz always exist irrespective of No. of poles. Therefore the vibration is generated in the stator end windings and the micro-crack is grown up inside the bars. After all, coolant water is leaked outside the bars or the stator is moved and is worn out. What is more, one bar is touched with another bar so a short circuit may frequently happen in operation. In order to prevent it from occurring, the evaluation of mechanical integrity for generator stator windings is carried out periodically during overhaul period. This help troublesome end windings to complement with insulation material and to change vibration characteristics. In this paper, the evaluation of mechanical integrity for generator stator windings is described and the change of vibration characteristics is analysed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.6
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• pp.8-12
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• 2017

This paper presents the mobile phone case for self-power generation and recharge for emergency calls or text messages at the discharge of a battery. If the user shakes his smart phone case, the interaction of electromagnetic coil and permanent magnet in an electric generator produces electric energy, which charges the lithium-ion battery. This enables the user to give a few calls or text messages. In addition, the vibration energy from humans walking at a frequency of 2 ~ 3Hz charges the battery. The electric generator was simulated using MAXWELL, a commercial electromagnetic analysis program, to analyze the electric power generation. Finally a prototype of the mobile phone case for self-power generation was built based on the analysis and its performance was verified.

• The Transactions of the Korean Institute of Power Electronics
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• v.11 no.3
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• pp.247-257
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• 2006

This paper shows the comparison of operating characteristics between squirrel cage induction generator and DFIG(Double Fed Induction Generator). Because squirrel cage induction generator consume the reactive power due to magnetizing reactance, the capacitor is need to compensate the reactive power. Otherwise, two back-to-back PWM voltage-fed inverters connected between the stator and the rotor allow sub/super synchronous operation with low distortion currents. In this paper, the response characteristics of squirrel cage induction generator and DFIG, were analyzed and investigated using PSCAD/EMTDC.

• 전기의세계
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• v.17 no.2
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• pp.27-31
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• 1968

최근 각종 회전전기의 설계제작에 있어서 그경제성과 신뢰성을 높이고저 가능한 한고속화 내지는 단일화 경향에 있다. 예로써 1,500MV급 주발전기라면 8MW라는 려자전력이 필요하므로 이를 종래의 직결직류려자기방식으로서는 정류조건에서 제한을 받게된다. 고로이러한 난문제의 해결책으로서 직류여자기의 감속, 별치의 M-G Set, 또는 이중전기자법등이 고찰되고 있으나 역시 과담한 경제문제를 수반하게 된다. 또한 각종산업의 발달에 따라 요구되는 부하특성과 가혹한 환경조건에서 운전되어야할 경우가 증가되고 있다. 즉 염소Gas, 아유산 Gas, 인화유기 또는 공해상등을 막론한 주위조건에서 방식방폭의 안정성과 소형경량화의 경제성등을 설계의 주요목적으로 본다. 이것은 회전전기의 고정자와 회전자간에 전달되는 전기적 Energy가 회전기계의 가장 약점인 탁동부분을 통과하기 때문이다. 여기에서 탁동부를 제거할 수단으로 Brushless 려자방식이 고안되었으며 오래전부터 그 Idea가 창안되어 있었으나 최근 갑자기 극소용량급에서 초대용량급에 이르기까지 Brushless화 되었음은 재료과학에서 본 자기증중기 또는 반도체공학의 발달이 크게 영향하였다. 필자는 여기에 발전기를 중심으로 Brushless 려자방식의 종류와 문제점을 검토하여 금후 발전될 전망에 대하여 간단히 논한다.

• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.142-145
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• 2008

Electrical insulation of small hydro generator stator winding is one of the most important parts in generator facilities. Some stator winding insulation problems can be identified through analysis of insulation diagnostic test. So, Diagnosis of stator winding insulation is an important measure of ensuring the safe operation and extending the remaining life of small hydro generator. This paper presents case studies of insulation failure in generator stator windings and the results of insulation diagnostic test for small hydro generator stator windings. Especially, Conducting the insulation diagnostic test before the generator installed in site is very important process to keep the good insulation condition in service.

• Proceedings of the KIEE Conference
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• 2006.11a
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• pp.390-392
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• 2006

대규모 전력계통인 한국전력과 154kV 송전선로로 연계되는 석유화학공장 전력계통에 작은 용량의 자가발전기가 병렬운전 되는 경우이다. 전기사고로 한국 전력과의 연계 송전선로가 개방되어 석유화학공장 전력계통이 단독으로 분리되면 발전이 수요에 크게 못 미치게 되어 급격한 주파수 저하 및 과도한 전압강하가 나타나고 이로 인하여 발전기가 정지되어 공장 전체가 정전에 이르게 되는 사고 가능성이 있다. 본 논문은 이와 같은 대규모 전력계통과의 연계선로 개방으로 나타나는 과부하 상태에서 주파수 안정화 및 전압강하에 대처할 수 있는 부하차단 또는 계통 분리로 수급 불균형을 해소하고, 단시간 전압강하 상태에서도 효과적으로 전력계통 안정화가 지속될 수 있는 방안 등을 전력계통 동특성 해석도구를 이용하여 모의하고 이를 실제 전력계통에 적용코자하는 사례 연구이다.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.479-480
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• 2015

단기 전력수급계획 시 미리 전력수요를 예측하고, 또 그때의 공급능력을 산정하는 일은 계통운영 측면에서 매우 중요한 과업중 하나이다. 각 발전기들은 시험기준 온도에 맞는 정격용량 값을 갖고 있지만, 실제 기온의 변화에 따라 각기 다른 출력변화를 갖게 되므로 계통운영자는 공급능력 산정 시 이러한 온도의 영향을 고려할 필요가 있다. 본 논문에서는, 온도를 고려한 공급능력 산정방안을 과거 실적 데이터 분석을 통한 두 가지 방법으로 제시해 보았다.