DC 변전소 몰드변압기 온라인 상태 감시 시스템 구현

박영(Young Park),정호성(Ho-Sung Jung),박철민(Chulmin Park),장순호(Soon-ho Jang) 대한전기학회 2011 전기학회논문지 Vol.60 No.9

The mold transformer is a complex and critical component of DC substations in Metro system. In this paper, a cost effective and intelligent condition monitoring system for mold transformers in DC substations was developed. This paper also provides an overview of the management program using PD (partial discharge) data on mold transformers. Prior to application of the proposed system to Metro DC substations, experiments were performed at the metro line substation located in Seoul and presented case studies for the use of the intelligent condition monitoring system for mold transformer in DC substations. The experiment results indicated that the developing system can be need in helping mange the risk of unexpected failure of mold type transformers.

선박용 몰드변압기 열해석

강한영(H.Y. Kang),전재근(J.G. Joun),정기삼(G.S. Jung),최종웅(J. W. Choi),박석원(S.W. Park),이종호(J.H. Lee) 한국전산유체공학회 2011 한국전산유체공학회 학술대회논문집 Vol.2011 No.11

The Mold transformers fire retardant and environmentally friendly equipment, such as oil leaks, etc. Since the ship has been used in many places. We analysis of the Marine mold transformers temperature with commercial code ICEPAK and we designed the best compact-size of transformer. In particular, this raper used in the AFWF(Air Forced and Water Forced) mold transformer, protection rating of the enclosure must be over 44 (IP code) and the life of the transformer is dependent on the thermal temperature of windings so the designers of transformer are predicted or calculated temperature distribution. In this paper, we pre-simulated of the transformers temperature and enclosure before final designed transformer and the results show a satisfactory results with actual temperature rise measurements obtained from thermal imaging camera.

몰드형 건식 계기용 변압기 제작을 위한 수지 충진 해석 연구

김무선(Moosun Kim),장동욱(Dong Uk Jang),김승모(Seung Mo Kim) 한국산학기술학회 2016 한국산학기술학회논문지 Vol.17 No.12

철도 차량에 쓰이는 기존 유입식 형태의 계기용 변압기는 장치 내부에 절연유가 충진 된 형태이므로, 차량 운행 중에 내부 압력이 상승할 수 있는 가능성이 있으며. 그에 따른 폭발위험성이 존재한다. 따라서 폭발 방지를 위해 몰드형 건식 계기용 변압기를 개발 중에 있다. 몰드형 건식 계기용 변압기 개발시 주의 하여야 할 점은 몰드를 구성하는 절연용 에폭시 수지를 주입할 때 권선 코일이 감겨진 코어 주변에 기공이 없어야 한다는 것이다. 이는 몰드 내부의 기공에서 스파크 등의 발생 위험이 있기 때문이다. 몰드 내의 기공 발생 요인으로는, 수지 내에 미세 기공(micro void)이 잔재되어 있는 경우와, 성형 중 함침구조물의 형태에 따라서 대형 기공(macro void)이 발생할 수 있는 점 등이다. 현재 개발 중인 코어는 변압기 성능 향상을 위해 중공(cavity)이 존재하는 형태이며 점도가 높은 에폭시 주입시 중공 내부에 대형 기공이 갇힐 위험이 있다. 따라서 이번 연구에서는, 몰드 내부에 발생할 수 있는 대형 기공의 형성 과정을 이해하고, 기공 형성 요인을 제거할 수 있는 방안으로, 개선된 성형 조건 적용시 기공 형성 결과를 확인하기 위해, 몰드 충진 과정을 VOF기법을 적용한 자유 표면 유동의 수치해석을 통하여 확인하였다. Current oil-type potential transformers for trains are filled with insulating oil, which could have problems like explosions due to rising inner pressure during train operation. Therefore, mold and dry-type potential transformers are being developed to prevent explosions. One problem in manufacturing mold-type transformers is preventing void formation around the coiled core inside the mold during epoxy filling, which could cause an electrical spark. Micro voids can remain in the resin after filling, and macro voids can occur due to the structure shape. A transformer that is being developed has a cavity at the junction of the core and the coil for better performance, and when highly viscous epoxy flows inside the cavity channel, macro voids can form inside it. Therefore, in this study, the free-surface flow of the mold filling procedure was analyzed numerically by applying the VOF method. The results were used to understand the phenomena of void formation inside the cavity and to modify the process conditions to reduce voids.

와전류 손실을 적용한 금형으로 제조된 초고압 변압기의 프레스보드의 절연 특성 연구

서왕벽,Suh, Wang-Byuck 한국전기전자재료학회 2015 전기전자재료학회논문지 Vol.28 No.8

Some insulating materials are tested and analyzed with variables to obtain the reliable pressboard which is located to core and coil of high voltage transformer. The high voltage transformer is used in electrical power system and operating reliability. Optimization possibility of pressboard shape including electrical insulation performance could be achieved by analysis simulation. Using insulating pressboard, which is made by mold applied eddy current loss, it could be measured the influences of moisture content for electrical properties. As a result, it is to contribute to improve the performance and ensure the reliability of the pressboard by investigating electrical strength according to the variation oil temperature. In addition pressboard thickness is important design factor to ensure electrical strength in high voltage transformer.

콘크리트 슬래브에 고정된 사용 후 몰드변압기의 지진 응답 특성

이상문(Sang-Moon Lee),전법규(Bub-Gyu Jeon),윤다운(Da-Won Yoon),김성완(Sung-Wan Kim),정우영(Woo-Young Jung) 한국소음진동공학회 2020 한국소음진동공학회 논문집 Vol.30 No.6

In this study, shaking table tests were conducted for the molded transformers used in hydropower plants. To implement the actual site conditions, the anchor bolt was installed and secured to the concrete slab with the load cell installed in the anchorage to observe and analyze the load generated by seismic on the anchor. The sine sweep waveform was applied in a short direction to determine the unique frequency of the sample. Moreover, the seismic waves in these shaking table tests were applied to artificial earthquakes (4 stages) that met the ICC-ES AC156 conditions and based on Pohang and Kyungju earthquakes. The results of the experiment show that there was no functional damage to the molded transformer. However, structural damage occurred after the Kyungju and Pohang earthquakes condition. The vibration transmission function of the lower frame was the highest, while for the uppermost frame was the lowest. Additionally, large relative displacement between the upper and lower parts caused by non-linear behavior of the lower frame may result in a collision or impact damage with the surrounding device or equipment.

2[MVA] 배전용 몰드변압기의 과도전계해석에 관한 연구

전문호(Mun-Ho Jeon),김창업(Chang-Eob Kim) 한국조명·전기설비학회 2010 조명·전기설비학회논문지 Vol.24 No.12

This paper presents the electric field for 22.9[㎸]/380[V], 2[MVA] mold transformer are analysed using FEM(finite element method). The electric field was calculated for the voltage applied to the transformer. Then, it is analysed that the maximum electric field occurred between high voltage turns. Capacitance is calculated with energy method. Surge impulse test simulation is studied by modeling circuit with capacitance and inductance. This paper obtain the result that is about influence of electric field in distribution mold transformer adopted.

Optimization of filling process in RTM using genetic algorithm

Kim, Byoung-Yoon,Nam, Gi-Joon,Ryu, Ho-Sok,Lee, Jae-Wook The Korean Society of Rheology 2000 Korea-Australia rheology journal Vol.12 No.1

In resin transfer molding (RTM) process, preplaced fiber mat is set up in a mold and thermoset resin is injected into the mold. An important interest in RTM process is to minimize cycle time without sacrificing part quality or increasing cost. In this study, the numerical simulation and optimization process in filling stage were conducted in order to determine the optimum gate locations. Control volume finite element method (CVFEM) was used in this numerical analysis with the coordinate transformation method to analyze the complex 3-dimensional structure. Experiments were performed to monitor the flow front to validate simulation results. The results of numerical simulation predicted well the experimental results with every single, simultaneous and sequential injection procedure. We performed the optimization analysis for the sequential injection procedure to minimize fill time. The complex geometry of an automobile bumper core was chosen. Genetic algorithm was used in order to determine the optimum gate locations with regard to 3-step sequential injection case. These results could provide the information of the optimum gate locations in each injection step and could predict fill time and flow front.

Dynamic characteristic analysis of mold oscillator including improved gear mesh model and cam profile for eccentric shaft

박용희,박현철 대한기계학회 2014 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.28 No.11

We propose a 3-dimensional model of a mold oscillator to predict how design parameters affect its dynamic characteristics. The modelconsiders the geometry of each part, and the relations between components. The proposed model considered the influence of the gearmesh and the geometry of the eccentric shaft on caster oscillation. The caster took a different excitation according the status of excitingforce transfer. Even though caster and driving crank were connected by an intermediate process, the angular velocity of the driving crankwas primarily shown as odd harmonic terms in the behavior of caster. Additionally, the gear mesh contact force determined the caster’soscillation at low frequency. To verify the model, the previous approach for designing oscillating system was compared to the suggestedmodel, and the sensitivity of the caster to the geometry of the eccentric shaft was analyzed. The gear mesh stiffness and the geometry ofeccentric shaft were represented by the Fourier series. The equation of motion for oscillating system was solved by the numerical method,NEWMARK. To analyze coupled motion, the dynamic response of coordinate was analyzed in the time-frequency domain using theFourier transform.

The Condition Assessment of Cast Resin Molded Transformer Windings Using Vertical Analysis of Thermal Distribution

Lim Young-Bae,Jung Jong-Wook,Jung Jin-Soo,Cho Seong won,Kim Joon-Bum The Korean Institute of Electrical Engineers 2005 KIEE International Transactions on Electrophysics Vol.5C No.5

This paper presents an assessment method in integrity of the windings in cast resin molded transformers by using vertical analysis of thermal distribution. The proposed method is to compare the temperature distribution in a sound specimen with that in the faulted specimen with a layer to layer short circuit. Temperature distribution was acquired by an infrared thermography system, and the Arrhenius equation was adopted to the accelerated test. The proposed method can be used to detect the failures in the transformers.

전기 비구조요소 (몰드변압기)실험 및 해석 기반 취약도 평가

이승재(Lee, Seung-Jae),김주영(Kim, Joo-Young),최경규(Choi, Kyung-Kyu) 대한건축학회 2019 대한건축학회 학술발표대회 논문집 Vol.39 No.1