• KIEE International Transactions on Electrophysics and Applications
• /
• 제5C권5호
• /
• pp.191-195
• /
• 2005

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.

• 조명전기설비학회논문지
• /
• 제19권2호
• /
• pp.94-99
• /
• 2005

본 논문은 수직온도분포 분석을 이용한 몰드변압기 권선의 건전성 평가 방법을 제시하고 있다. 이 방법은 건전 시료의 온도 분포와 가속열화실험에 의해 층간 단락된 고장시료의 온도 분포 비교를 통해 얻어진 결과이다. 분석에 활용된 온도분포는 적외선 열화상 시스템에 의해 취득되었고, 가속 열화시험에는 Arrhenius 방정식이 적용되었다. 제안된 방법은 몰드변압기 고장을 검출하는데 유용할 것이다.

• 한국가스학회지
• /
• 제12권4호
• /
• pp.58-62
• /
• 2008

본 연구에서는 직렬 6기통 압축천연가스 엔진의 피스톤에 대한 3차원 모델링을 수행하여 정상상태에서의 온도분포 및 그에 따른 열응력과 변형을 예측하고, 이를 기존의 해석결과와 비교 검토를 통하여 피스톤의 유한요소해석의 기준을 구축하고자 한다. 또한 냉각시스템의 성능이 피스톤의 열부하에 미치는 영향을 평가하기 위하여 냉각수 온도의 변화에 따른 피스톤의 온도분포 및 열응력 분포 그리고 그에 따른 변형을 분석하였다. 분석결과 피스톤의 최고 온도는 크라운부의 중앙에서 나타났고, 피스톤의 크라운 하부에서 최대 열응력이 발생하였다.

• 문화기술의 융합
• /
• 제9권5호
• /
• pp.737-745
• /
• 2023

본 논문은 열화상 이미지를 활용하여 배전반 화재 발생을 감지하기 위한 인공지능 모델을 개발하는 연구에 대해 다룬다. 연구의 목표는 수집한 열화상 이미지를 전처리하여 객체 탐지 모델에 적합한 데이터로 가공하고, 이를 이용하여 배전반 내 화재 발생 여부를 판단하는 모델을 설계하는 것이다. 연구에서는 AI-HUB의 산업단지 내 학습용 열화상 이미지 데이터를 활용하였으며, CNN 기반 딥러닝 객체 검출 알고리즘 중 대표적인 모델인 Faster R-CNN과 RetinaNet을 사용하여 모델을 구축하고 두 개의 모델을 비교 분석하여 최적의 모델을 제안하고 있다.

• 한국조명전기설비학회:학술대회논문집
• /
• 한국조명전기설비학회 2004년도 학술대회 논문집
• /
• pp.315-319
• /
• 2004

This paper presents the integrity evaluation method of the windings in cast resin transformers using vertical thermal distribution analysis. The method is to compare the temperature distribution in a sound condition specimen with that in the failure condition specimen layer-shorted by accelerated testing. The temperature distribution was acquisited by a infrared thermography system, and the Arrhenius equation was adopted to the accelerated testing. The proposed method may be available to detect the failures in cast resin transformers.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2000년도 하계학술대회 논문집 C
• /
• pp.1900-1902
• /
• 2000

In this paper, the temperature distribution and thermal stress analysis of mold transformer for power distribution system is investigated by FEM. Filler type epoxy is applied for good cooling effect in mold transformer.

• 대한기계학회논문집
• /
• 제15권2호
• /
• pp.567-574
• /
• 1991

In this study thermal stress generated in three ingot moulds(GC25) during the solidification process of aluminum were analyzed by the two-dimensional thermo-elasto-plastic theory. In temperature analysis, all of the three models are shown steep temperature rising each case in initial stage of cooling. In thermal stress analysis, all of three models took compressible stress on inside wall of the mould, and tensible along with on out side. Model 2 take place less compressible, tensible stress then model 1. But model 3. have similar as thermal stress as model 2. The analysis will made one possible to calculate an optimum mould shape whose thermal stress gradient becomes minimum.

• 한국생산제조학회지
• /
• 제22권3호
• /
• pp.380-387
• /
• 2013

In this study, two finite element (FE) models were developed to evaluate the thermal characteristics of a feeding axis of a CNC lathe. One was used for analysis of heat transfer to identify the temperature distribution of the feeding axis and then, the other was used for analysis of thermal deformation to evaluate its structural behavior based on the temperature distribution. The FE models were based on the test standard for the axial thermal displacement. The feeding velocity was composed of three steps: the ascending, constant, and descending velocities. Therefore, the heat generation and convection coefficient were calculated for each velocity and applied to the thermal FE model. The convection coefficient for the ball screw rotation was based on an experimental equation. The result of the analytical thermal displacement was compared with that of the experimental displacement to verify the finite element models.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2002년도 추계학술대회 논문집
• /
• pp.980-984
• /
• 2002

This paper has studied thermal characteristics of machine tool to develope high speed spindle and optimum design condidering the thermal deformation. Comparing the test data of temperature measurement and structural analysis data using FEM, we verified the test validity and predicted thermal deformation, influence of spindle generation of heat, and established cooling system to prevent the thermal deformation. 1) The temperature rise of spindle system depends on increasing number of rotation and shows sudden doubling increment of number of rotation over 7,000rpm. 2) Oil jacket cooling can be effective cooling method below 8,000rpm but, over 8,000rpm, it shows the decrement of cooling effect. 3) Comparing FEM analysis results and revolution test results, we can confirm approximate temperature change consequently, it is possible to simulate temperature rise and thermal distribution on the inside of spindle system. 4) We can confirm that simulated approach by FEM analysis can be effective method in thermal-appropriate design.

• 설비공학논문집
• /
• 제16권2호
• /
• pp.111-120
• /
• 2004

The optimal design method of indoor thermal environment using CFD coupled simulation and genetic algorithms (GA) is developed in this study. CFD could analyze the thermal environment considering the distribution of temperature, velocity, etc. in a room. Therefore, It would be appropriate to use CFD for the optimal design method considering their distribution. In this paper, the optimal design means the most appropriate boundary conditions of the room among the conditions where the design target of indoor therm environment is achieved. Two step optimal indoor thermal environment design method is proposed. It includes the GA for searching the optimal indoor thermal environment design. To examine the performance of this method, the optimal design of hybrid ventilation system, which uses the natural cross ventilation and the radiation-cooling panel is conducted. The optimal design which satisfies the design target (thermal comfort, minimum cooling load, minimum vertical temperature difference) is found using two step optimal design method.