회복 전압 인가 방식의 잔류 아크 폭발 차단용량 시험 설비 설계

김은민,노성여 대한전기학회 2024 전기학회논문지 Vol.73 No.8

For secondary battery overcurrent protection devices, it is essential to perform breaking capacity tests to verify their safety in the context of explosive current events resulting from electrical mobility breakdown during the electrophoresis process and explosive fire incidents caused by post-arc phenomena. However, constructing a high-capacity DC power supply test system for breaking capacity entails considerable expenses in equipment configuration. In this study, a low-voltage high-current DC power source is employed to switch a low-current high-voltage power supply device designed an operational procedure. A system capable of conducting high breaking capacity tests with low-capacity DC power facilities is designed and confirmed the absence of statistically significant differences in the I-T curve test of overcurrent protection devices, initial current breaking capacity, and the limit test for residual arc explosion capacity. The reliability of the tests is established through comparative breaking capacity assessments with high-power supplies.

DC/DC 컨버터의 단락특성을 반영한 저압직류계통의 단락용량 산출방안에 관한 연구

오찬혁,이기연,채동주,임승택 대한전기학회 2023 전기학회논문지 Vol.72 No.11

In recent years, many studies have been conducted on DC distribution systems and commercialization attempts have been made, but they suffer from the lack of requirements for low-voltage direct current. This paper proposes a short-circuit capacity calculation method for low-voltage direct current systems by considering the short-circuit characteristics of DC/DC converters. In order to consider the different short-circuit fault behaviors of each converter, the equivalent capacitor capacity of the output terminal of the converter and the maximum output current of the converter are provided by the converter manufacturer. Using this, the short-circuit capacity is calculated by mixing the short-circuit characteristics of the converter output terminal capacitor and the short-circuit current supply characteristics due to the switching control of the converter. The proposed method is verified using Matlab/Simulink simulation to examine the appropriateness of the short-circuit capacity calculation method using the proposed method.

Analysis on Temperature Distribution and Current-Carrying Capacity of GIL Filled with Fluoronitriles-CO₂ Gas Mixture

Chen, Geng,Tu, Youping,Wang, Cong,Cheng, Yi,Jiang, Han,Zhou, Hongyang,Jin, Hua The Korean Institute of Electrical Engineers 2018 Journal of Electrical Engineering & Technology Vol.13 No.6

Fluoronitriles-$CO_2$ gas mixtures are promising alternatives to $SF_6$ in environmentally-friendly gas-insulated transmission lines (GILs). Insulating gas heat transfer characteristics are of major significance for the current-carrying capacity design and operational state monitoring of GILs. In this paper, a three-dimensional calculation model was established for a GIL using the thermal-fluid coupled finite element method. The calculated results showed close agreement with experimentally measured data. The temperature distribution of a GIL filled with the Fluoronitriles-$CO_2$ mixture was obtained and compared with those of GILs filled with $CO_2$ and $SF_6$. Furthermore, the effects of the mixture ratio of the component gases and the gas pressure on the temperature rise and current-carrying capacity of the GIL were analyzed. Results indicated that the heat transfer performance of the Fluoronitriles-$CO_2$ gas mixture was better than that of $CO_2$ but worse than that of $SF_6$. When compared with $SF_6$, use of the Fluoronitriles-$CO_2$ gas mixture caused a reduction in the GIL's current-carrying capacity. In addition, increasing the Fluoronitriles gas component ratio or increasing the pressure of the insulating gas mixture could improve the heat dissipation and current-carrying capacity of the GIL. These research results can be used to design environmentally-friendly GILs containing Fluoronitriles-$CO_2$ gas mixtures.

Analysis on Temperature Distribution and Current-Carrying Capacity of GIL Filled with Fluoronitriles-CO₂ Gas Mixture

Geng Chen,Youping Tu,Cong Wang,Yi Cheng,Han Jiang,Hongyang Zhou,Hua Jin 대한전기학회 2018 Journal of Electrical Engineering & Technology Vol.13 No.6

Fluoronitriles-CO₂ gas mixtures are promising alternatives to SF6 in environmentallyfriendly gas-insulated transmission lines (GILs). Insulating gas heat transfer characteristics are of major significance for the current-carrying capacity design and operational state monitoring of GILs. In this paper, a three-dimensional calculation model was established for a GIL using the thermal-fluid coupled finite element method. The calculated results showed close agreement with experimentally measured data. The temperature distribution of a GIL filled with the Fluoronitriles-CO₂ mixture was obtained and compared with those of GILs filled with CO₂ and SF6. Furthermore, the effects of the mixture ratio of the component gases and the gas pressure on the temperature rise and current-carrying capacity of the GIL were analyzed. Results indicated that the heat transfer performance of the Fluoronitriles-CO₂ gas mixture was better than that of CO₂ but worse than that of SF₆. When compared with SF6, use of the Fluoronitriles-CO₂ gas mixture caused a reduction in the GIL’s current-carrying capacity. In addition, increasing the Fluoronitriles gas component ratio or increasing the pressure of the insulating gas mixture could improve the heat dissipation and current-carrying capacity of the GIL. These research results can be used to design environmentally-friendly GILs containing Fluoronitriles-CO₂ gas mixtures.

Operating Characteristics of Hybrid Type Superconducting Fault Current Limiter

趙鎔善(Yong-Eun Cho),崔孝祥(Hyo-Sang Choi),南肯賢(Gueng-Hyun Nam),林成勳(Sung-Hun Lim) 대한전기학회 2006 전기학회논문지A Vol.55 No.6

We investigated the operating characteristics of the hybrid-type superconducting fault current limiter (SFCL) according to the inductance of secondary windings. The hybrid type SFCL consists of a transformer that has a primary winding and a secondary winding with serially connected YBa₂Cu₃O? (YBCO) films. The resistive-type SFCL has difficulty when it comes to raising the capacity of the SFCL due to slight differences of critical current densities between units and structure of the SFCL. The hybrid-type SFCL with closed-loop is able to achieve capacity increase through the electrical isolation and reduction of the inductance of the secondary winding with a superconducting element of the same critical current. On the other hand, the current limiting characteristics were nearly identical in the hybrid-type SFCL with open-loop compared to closed-loop, but quench time was longer than the hybrid-type SFCL with closed-loop. We confirmed that the capacity of the SFCL was increased effectively by the reduced inductance of the secondary winding. In addition, the power burden of the system also could be lowered by reducing the inductance of secondary winding.

송전선로의 설비특성을 고려한 운영그룹 분류 및 최고허용온도

孫洪寬(Hong-Kwan Sohn),金秉杰(Byung-Geol Kim),朴寅杓(In-Pyo Park),安相炫(Sang-Hyun An),張太因(Tae-In Jang),崔鍾基(Jong-Kee Choi) 대한전기학회 2008 전기학회논문지 Vol.57 No.11

The thermal rating of a conductor are maximum continuous current capacity and short time emergency current capacity. The overload operation for a faults have an effect on a conductor lifetime. Its time duration and overload level are limited to facility conditions of transmission lines. The short time emergency current capacity in KOREA observe the KEPCO's DESIGN RULE 1210, but its rules are not included to concept of an allowable short time duration. This papers are described to the calculation concept of short time emergency current capacity considering a time duration and an overload level. And we suggested a operation grouping and its maximum conductor temperature considering facility conditions - conductor lifetime, stability of connection points, conductor height above ground and clearance, in the operating and new T/L.

Improvement on the power capacity of the transformer-type SFCL with neutral lines between secondary windings

Cho, Y.S.,Choi, H.S. North-Holland 2009 Physica. C, Superconductivity Vol.469 No.15

Application of the superconducting fault current limiter (SFCL) to the power system requires connection of superconducting elements in parallel and series. The uneven critical property of the superconducting element, however, causes unbalanced quenching. This brings the increase in power burden to a specific superconducting element. To solve this problem, a transformer-type SFCL with neutral lines was studied. In this paper, the fault current-limiting characteristics and consumption power of the superconducting element were analyzed. As a method to increase the power capacity of the transformer-type SFCL, the number of secondary circuits of the transformer was also increased. As a result, we found that the voltage and current of the superconducting elements were efficiently controlled by turn ratios of the transformer. This structure resulted in minimized consumption power. The transformer-type SFCL with neutral lines induced the simultaneous quenching between superconducting elements. This enabled us to increase the number of secondary circuits. Therefore, it induced the increase in its power capacity in the transformer-type SFCL.

154kV XLPE 600㎟ 지중관로 수평배열 형태별 허용전류용량 산정에 관한 연구

김세동,유상봉,Kim, Se-Dong,Yoo, Sang-Bong 한국조명전기설비학회 2016 조명·전기설비학회논문지 Vol.30 No.3

The underground transmission lines which have been built to expand the suppling facilities will be continuously accompanying with high growth of the increase of power demand in the metropolitan area in recent years. So, it is necessary to maximize the ability and reliability of power supply with the current-carrying capability of the underground transmission lines. Design criteria of KEPCO is to be presented and used frequently. But it has to be studied about the installation methods of power cable buried in ground. In this study, we used the program for calculating the current-carrying capability of underground transmission power cables. We estimated the maximum permissible current values by the horizontal arrangement in the installation methods of power cable(154kV XLPE $600mm^2$) buried ducts in ground. To see the general tendency of the analysis, we researched a statistical analysis with such parameters as the maximum permissible current values. Through the regression analysis, we analyze the most highly values of the maximum permissible current on the Ra type duct arrangement.

유도전동기 직입 기동시 전압강하와 변압기 용량에 관한 연구

김종겸,박영진 한국조명.전기설비학회 2022 조명·전기설비학회논문지 Vol.36 No.3

The biggest disadvantage of an induction motor is that the voltage drop is large due to the high current during startup. Voltage drop is an electrical and mechanical problem for the motor itself, but it can also be a major problem for other connected loads. Therefore, it is necessary to limit the voltage drop within a certain range. Transformer capacity is a factor that greatly affects the voltage drop when starting an induction motor. If the capacity of the motor is more than a certain size among the loads connected to the transformer, it is necessary to examine the voltage drop. In this paper, after calculating the capacity of the transformer corresponding to the permissible range of the voltage drop, we analyzed how the voltage drop varies according to the value of % impedance. As a result of the analysis, it was found that increasing the transformer capacity is effective to reduce the voltage drop, and it is more advantageous to lower the% impedance even for a transformer of the same capacity.

사질토층을 지나 풍화암에 소켓된 매입 PHC말뚝에서 지반의 허용압축지지력 산정도표 및 산정공식 개발에 관한 연구(IV) - 압축정재하시험 및 양방향재하시험 자료 분석을 통한 매입 PHC말뚝의 장기허용압축하중의 실증 성능 검증 -

이원제,김채민,윤도균,최용규 한국지반공학회 2019 한국지반공학회논문집 Vol.35 No.9

Axial compressive failure loads () of diameter 500 mm and diameter 600 mm A type PHC pile were calculated as 7.7 MN and 10.6 MN, respectively. In the static pile load tests, the maximum axial compressive loads of the above 2 kinds of A type pile were measured as 6.9 MN and 8.8 MN respectively, therefore these measured maximum loads were at the level of 90% and 83% of respectively. Long-term allowable axial compressive loads () of the above 2 kinds of A type pile were 1.7 MN and 2.3 MN respectively. From the bi-directional pile load test data on the prebored PHC piles, it was confirmed that the allowable axial compressive bearing resistance was estimated as 131% of the long-term allowable compressive load of the PHC pile and showed higher than the allowable bearing capacity calculated by the current design method. Therefore, it has been verified that the PHC pile can be used up to the maximum long-term allowable compressive load, and it is suggested that the ultimate pile capacity formula used in the current design for prebored PHC piles should be improved to accommodate the actual capacity.