• 에너지공학
• /
• 제20권3호
• /
• pp.185-190
• /
• 2011

본 논문은 초전도 에너지 저장장치(SMES)용 전도냉각형 고온초전도 자석의 설계, 제작 및 평가에 대해 기술한다. 고온초전도 자석은 황동 안정화재를 갖는 2개의 Bi-2223 다심 선재가 적층된 4-ply 도체로 제작된 22개의 double pancake coil(DPC)로 구성된다. 그리고, 각 DPC는 내경과 외경이 각각 500 mm, 691 mm이고 높이가 10 mm인 2개의 single solenoid coil로 구성된다. 코일 내부의 전기적 손실에 의해 발생된 열의 냉각을 위하여 DPC 사이에 두께 3 mm의 알루미늄 판이 내재된다. 고온초전도 자석은 2단 Gifford McMahon 냉동기에 의해 5.6 K까지 냉각된다. 충전전류가 증가할수록 방전시 고온초전도에서의 최대 온도가 증가 하였다. 충전전류가 360 A일 때 ��치 없이 고온초전도 자석에 1 MJ의 자기에너지가 성공적으로 저장되었다. 본 연구에서는 SMES용 전도 냉각형 고온초전도자석에 대한 열적, 전자기적 특성을 보이고, 본 연구를 통해 얻어진 결과는 전도냉각형 고온초전도자석의 최적설계 및 안정도 평가에 활용될 것이다.

• 대한전기학회논문지:전기물성ㆍ응용부문C
• /
• 제55권8호
• /
• pp.404-410
• /
• 2006

Toward the practical applications, on operation of conduction-cooled HTS SMES at temperatures well below 40[K] should be investigated, in order to take advantage of a greater critical current density of HTS and considerably reduce the size and weight of the system. In order to take advantage of a greater critical current density of high temperature superconducting (HTS) and considerably reduce the size and weight of the system, conduction-cooled HTS superconducting magnetic energy storage (SMES) at temperatures well below 40[K] should be investigated. This work focuses on the breakdown and flashover phenomenology of dielectrics exposed in air and/or vacuum for temperatures ranging from room temperature to cryogenic temperature. Firstly, we summarize the insulation factors of the magnet for the conduction cooled HTS SMES. And Secondly a surface flashover as well as volume breakdown in air and/or vacuum with two kind insulators has been investigated. Finally, we will discuss applications for the HTS SMES including aging studies on model coils exposed in vacuum at cryogenic temperature. The commercial application of many conduction-cooled HTS magnets, however, requires refrigeration at temperatures below 40[K], in order to take advantage of a greater critical current density of HTS and reduce considerably the size and weight of the system. The magnet is driven in vacuum condition. The need to reduce the size and weight of the system has led to the consideration of the vacuum as insulating media. We are studying on the insulation factors of the magnet for HTS SMES. And we experiment the spacer configure effect in the dielectric flashover characteristics. From the results, we confirm that our research established basic information in the insulation design of the magnet.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2009년도 제40회 하계학술대회
• /
• pp.2219_2220
• /
• 2009

The characteristics of the Superconducting Magnetic Energy Storage (SMES) system are faster response, longer life time, more economical, and environment friendly than other Uninterruptible Power Supply (UPS) using battery. Fast charge and discharge time of SMES system can provide powerful performance of improving power quality in the grid. In order to demonstrate the effectiveness of SMES, the authors make a 10kJ SMES system for connection with RTDS (Real Time Digital Simulator). Because the characteristics of superconducting magnet are very important in SMES system, the necessary items such as thermal characteristic, mechanical stress and protection circuit should be considered. In this paper, the authors experimented thermal characteristics of the 10kJ SMES system. The experiment was accomplished using a simulation coils made of aluminium. It has same dimension of the 10kJ class HTS SMES coil. The coil was cooled with GM (Gifford -McMahon) cryocooler through the OFHC (Oxgen Free High thermal Conductivity) conduction bar. The test results of cool down and heat loads characteristics of the simulation coils are described in detail.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2002년도 하계학술대회 논문집 B
• /
• pp.1361-1363
• /
• 2002

Micro-SMES(Superconducting Magnetic Energy Storage) has been studied as an impulsive high power supply for industrial applications. Recently, electric power reliability of our country has been improved. However, there are still remaining problems which are short-duration variations like instantaneous and momentary interruption and voltage sag by nature calamity ; typhoon, lightning, snow, etc. Besides, power quality ; harmonics, goes down because of using power electronics equipments. Malfunction of controller and stop machinery, and losing important data are caused by poor power quality at a couple of second in accuracy controllers. Due to those, battery based UPS has been used, but there are several disadvantages ; long charge and discharge time, environmental problem by acid and heavy metal, and short life time. Micro-SMES is an alternative to settle problems mentioned above. However, there need huge system apparatuses in order to verify the effect of system efficiency and stability considering the size of micro-SMES, the sort of converter type, and various conditions. This paper presents a cost effective simulation method of micro-SMES and power converter, and design for micro-SMES based system using PSCAD/EMTDC.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1991년도 하계학술대회 논문집
• /
• pp.386-392
• /
• 1991

If we rely only on the conventional technology, It may be difficult to meet the recent requirments to electric power system such as further improvement of the quality of electric power supply, technology problems environmental compatibility and so on. Nowadays, power engineers much interest in applying new technology to power system industry. It is confirmed the technology of superconductivity applied components plays an important role in solving the problems of power system, because superconductors, used in suitable applications, can make electric power equipment smaller, lighter, more efficient and perhaps with better dynamic response. Two specific applications are considered here : electric machinery (Generators, Superconducting Magnetic Energy Storage, Transformer, Current limitter) and transmission line. The paper addresses the limitation of conventional technology, the technology impact & problems of superconductivity applied components to future power system from qualitative and some quantitative viewponts. The paper close with questions posed to simulate thinking on how superonductivity might be applied to power systems on a holistic basis.

• 한국자기학회지
• /
• 제23권2호
• /
• pp.62-67
• /
• 2013

본 논문에서는 전자기 관련 제품의 효율적인 신뢰도 기반 최적설계를 위해 확률구속조건을 평가하는 기법으로 해의 안정성과 효율성이 우수한 목표 성능치법을 제시 하였다. 목표 성능치법을 적용한 신뢰도 기반 최적설계의 효율성 검증을 위하여 스피커 모델과 초전도 자기에너지 저장장치 모델에 대한 최적설계를 수행하였고, 이를 기존 신뢰도 지수법을 적용한 최적설계 결과와 비교하였다. 또한 몬테카를로 수치모사기법을 이용하여 도출된 최적해의 신뢰도를 재 계산 후 비교함으로써 제안된 기법의 신뢰도 평가 결과의 정밀도를 검증하였다.

• 전기학회논문지
• /
• 제62권1호
• /
• pp.49-56
• /
• 2013

In this paper, for constrained optimization problem, one multi-objective optimization algorithm that ensures both performance robustness and constraint feasibility is proposed when uncertainties are involved in design variables. In the proposed algorithm, the gradient index of objective function assisted by design sensitivity with the help of finite element method is applied to evaluate robustness; the reliability calculated by the sensitivity-assisted Monte Carlo simulation method is used to assess the feasibility of constraint function. As a demonstration, the performance and numerical efficiency of the proposed method is investigated through application to the optimal design of TEAM problem 22--a superconducting magnetic energy storage system.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2015년도 제46회 하계학술대회
• /
• pp.1120-1121
• /
• 2015

대용량 SMES(Superconducting Magnetic Energy Storage)를 제작하기 위해서는 높은 자장특성을 가고 있는 2세대 HTS(High-Temperature Superconductor) 선재를 사용하는 것이 효율적이다. SMES의 에너지밀도를 높이기 위해서는 선재에 많은 전류를 흘려야 하는데, 수직자기장이 커지면 임계전류가 작아지는 2세대 HTS 선재의 특성상 토로이드형태의 SMES가 유리하다. SMES를 설계하기 전에 선재의 사용량을 줄이고 체적을 줄이기 위해서 정확한 설계와 평가가 필요하다. 유한요소법을 사용한 상용프로그램을 이용하여 쉽게 해석할 수 있으나 토로이드 형태의 SMES는 대칭성의 문제로 3차원 해석을 해야만 한다. 그러나 2차원 해석에 비해 여러 가지 제약조건이 따르며 해석 시간이 많이 소요된다. 본 논문에서는 이러한 문제점을 해결하기 위해 분석적이고 통계적으로 고온 초전도 코일에서 작용하는 최대 수직자장을 결정하는데 이해하기 쉽고 효율적으로 계산하는 방법을 제시했다. 본 논문에서는 싱글펜케이크코일의 크기에 따른 최대 자장값을 계산하였고 싱글펜케이크코일이 토로이드형태로 배치된 토로이드 모델에서 주변코일이 싱글펜케이크코일의 미드포인트에 미치는 자장값을 계산하여 두 계산값을 합하는 방식으로 최대 자기장을 계산하였다. 이 방법은 현저한 시간단축과 효율적인 설계를 할 수 있는 새로운 계산 방법으로 기존 FEM을 사용해 걸리는 시간에 비해 1/1000정도의 시간단축을 할 수 있었다.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2009년도 제40회 하계학술대회
• /
• pp.599_600
• /
• 2009

In superconducting magnetic energy storage (SMES) systems, the current leads are usually divided into two parts. Normal metals like brass or copper are often used in the first part from the room temperature to the 1st stage of the cryocooler. Their dimensions were decided to minimize the conduction heat penetration and Ohm's heat generation. The second part down to the cryogenic coil is made of high temperature superconductor (HTS). HTS current leads can reduce the conductive heat penetration because they have poor thermal conductivity and generate no Ohm's heat generation. The brass current lead and the HTS current lead were designed and fabricated for application to the 10kJ class SMES system. The HTS current lead is 300A class. The HTS current lead was stacked with 2 HTS layers using the $Bi_2Sr_2Ca_2Cu_3O_x$ (BSCCO)/Ag. In this paper, we introduce the design procedure of the current leads and discuss the test results of the current leads.