• Title, Summary, Keyword: Current capacity

Search Result 2,296, Processing Time 0.039 seconds

Complementary Calculation of Current Carrying Capacity for Bare Overhead Conductors (가공선용 나전선의 허용전류 산정 보완)

  • Son, Hong-Gwan;Lee, Eun-Ung
    • The Transactions of the Korean Institute of Electrical Engineers A
    • /
    • v.51 no.5
    • /
    • pp.225-231
    • /
    • 2002
  • Many standards have Published for calculating of current carrying capacity for bare overhead conductors. Although these standards use the same basic heat balance concept, they use different approaches to calculate current carrying capacity, This paper looks at the four approaches used to calculate individual heat balance terms, at the overall impact of these terms on the current carrying capacity And this paper is proposed to the selection of proper standard and AC resistance within a country conditions for calculating the current carrying capacity of bare overhead conductors. So current carrying capacities are Proposed to some of conductors.

Analysis on the Application Capacity of the Superconducting Fault Current Limiter considering Reclosing and Fault Current (전력계통에 초전도한류기 적용시 차단용량 확보를 위한 초전도한류기 적용방안 연구)

  • Kim, Jin-Seok;Lim, Sung-Hun;Kim, Jae-Chul
    • Proceedings of the KIEE Conference
    • /
    • /
    • pp.592-593
    • /
    • 2015
  • Recently, the fault current has increased to exceed the rated breaking capacity of protective device due to the growth of the power demand on the power system where is changed into the loop-, mesh-, network grid. To limit fault current, the superconducting fault current limiter (SFCL) is announced with various methods. In many researches, the current limiting effect with the SFCL has been analyzed considering the rated breaking capacity of the CB with one fault condition. However, the power system has various short circuit and operation conditions. In order to select the capacity of the SFCL with reclosing operation and burden of the fault current on the protective device, the characteristics of the power system were investigated. Through the analysis, the evaluation method of the current rate was improved.

  • PDF

Capacity Requirement Estimation of Shunt Active Power Filter for Thyristor Converter Load (싸이리스터 컨버터부하에 적용되는 병렬형 능동필터의 적정용량산정)

  • Park, No-Jung;Jeong, Seung-Gi
    • The Transactions of the Korean Institute of Electrical Engineers B
    • /
    • v.48 no.12
    • /
    • pp.715-726
    • /
    • 1999
  • This paper estimates the capacity of shunt type active power filters(APF) for harmonic/reactive power compensation with a thyristor converter load. The base capacity requirement of APF is defined for idealized converter load current waveform and the effect of commutation overlap on the APF capacity is examined. The APF capacity required for reactive power compensation in addition to the harmonic elimination is estimated to give maximum achievable power factor for various operating condition of the partially-loaded thyristor converter. The method of current limit of APF is introduced, and it is shown that the APF capacity can be considerably reduced by deliberately limiting the peak current while maintaining the filtering performance to meet the level std 519 regulation.

  • PDF

Study on Current Capacity of the SC Conductor for $\mu$SMES Coil ($\mu$SMES 코일용 초전도도체의 전류용량에 관한 연구)

  • Kim, H.J..;Seong, K.C.;Cho, J.W.;Jin, H.B.;Ryu, K.S.;Ryu, K.
    • Progress in Superconductivity and Cryogenics
    • /
    • v.1 no.1
    • /
    • pp.22-27
    • /
    • 1999
  • Recently, small-sized superconducting magnetic storage($\mu$SMES) coils become commercially as an energy storage device for a power conditioner. In design and fabrication of the $\mu$SMES coils, to determine optimum current capacity of the superconducting(SC) conductors is one of the important things. We thus investigated the effect of conductor's current capacity, current density, and stability on the coil's maximum stored energy density in consideration of AC losses and switching device's capacities in a power converter. The results show that the smaller current capacity of the SC conductors is preferred for the $\mu$SMES coils but can increase their induced voltage excessively.

  • PDF

Study(II) on Development of Charts and Formulae Predicting Allowable Axial Bearing Capacity for Prebored PHC Pile Socketed into Weathered Rock through Sandy Soil Layer - Improvement Measures of Current Design Method by Analyzing Current Design Data for Prebored PHC Piles - (사질토층을 지나 풍화암에 소켓된 매입 PHC말뚝에서 지반의 허용압축지지력 산정도표 및 산정공식 개발에 관한 연구(II) - 설계 사례 분석을 통한 매입 PHC말뚝의 설계 개선 방향 -)

  • Yea, Geu Guwen;Yun, Dae Hee;Yun, Do Kyun;Choi, Yongkyu
    • Journal of the Korean Geotechnical Society
    • /
    • v.35 no.8
    • /
    • pp.31-42
    • /
    • 2019
  • A total of 73 pile design data for prebored PHC piles was analyzed to study the current design method. Based on the design data, a ratio of skin friction to total capacity from the pile design data was about 20~53%. Such low ratio of skin friction to total capacity tends to underestimate skin friction. Considering this tendency, the current design method should be improved. Also, an average design efficiency of PHC pile capacity was 70% and an average design efficiency for bearing capacity of soil or weathered rock was 80%, which shows slightly higher value than the former. This is probably due to the fact that the allowable bearing capacity is estimated to be equal to or slightly higher than the design load. Hence, the allowable bearing capacity should be estimated to be higher than the long-term allowable compressive force of the PHC pile. In the current design method, skin friction is calculated to be about 2.2 times lower than end bearing. The current design method for prebored PHC piles applied foreign design methods without any verification of applicability to the domestic soil or rock condition. Therefore, the current design method for prebored PHC piles should be improved.

Circulating Current Control in MMC-HVDC Considering Switching Device Current Capacity under Unbalanced Voltage Conditions (전압 불평형 조건에서 스위칭 소자의 전류용량을 고려한 MMC-HVDC 순환전류 제어기법)

  • Kim, Chun-Sung;Jung, Seung-Hwan;Hwang, Jung-Goo;Park, Seong-Mi;Park, Sung-Jun
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
    • /
    • v.30 no.1
    • /
    • pp.55-65
    • /
    • 2016
  • This paper proposed a new control method which is capable of controlling circulating current considering current capacity of switching device. In the unbalanced voltage conditions, active power and reactive power have double line frequency. Thus, in order to provide active power without ripple, it is necessary to inject the negative sequence current components. However, when the negative current components is injected, it increases the total current flowing in the Arm, and in the Sub-module(SM) the current more than rated is impressed, which leads to destroy the system. Also, in impressing the circulating current reference of each arm, conventional control method impressed applicable $i_{dck}/3$ in the case of balanced voltage conditions. In the case of unbalanced conditions, as arm circulating current of three phase show difference due to the power impressed to each arm, reference of each arm is not identical. In this study, in the case of unbalanced voltage, within permitted current, the control method to decrease the ripple of active power is proposed, through circulating current control and current limitations. This control method has the advantage that calculates the maximum active power possible to generate capacity and impressed the current reference for that much. Also, in impressing circulating current reference, a new control method proposes to impress the reference from calculating active power of each phase. The proposed control method is verified through the simulation results, using the PSCAD/EMTDC.

An Operation Grouping and Its Maximum Allowable Conductor Temperature Considering Facility-conditions of Transmission Lines (송전선로의 설비특성을 고려한 운영그룹 분류 및 최고허용온도)

  • Sohn, Hong-Kwan;Kim, Byung-Geol;Park, In-Pyo;An, Sang-Hyun;Jang, Tae-In;Choi, Jang-Kee
    • The Transactions of The Korean Institute of Electrical Engineers
    • /
    • v.57 no.11
    • /
    • pp.1922-1928
    • /
    • 2008
  • 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.

A study of joining method of BSCCO(2223) tape (Bi-2223초전도 선재의 접합공정 연구)

  • 김정호;김태우;주진호;서수정
    • Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
    • /
    • /
    • pp.18-21
    • /
    • 1999
  • The effects of joining process such as contact method, shape of joined area and pressure on the properties of Bi-2223 superconducting tape have been optimized. In the process tapes were etched to expose the superconductor core in the shape of 'ㅁ' and 'ㄷ'. The exposed cores of the two tapes were brought into contact, uniaxially pressed and sintered. Subsequently, the current capacity of the joined tape was measured as a function of uniaxial pressure. It was observed that the current capacity was significantly dependent on uniaxial pressure. The joined tape, fabricated with a pressure of 1,600 MPa, showed the highest value of current capacity(90%) of highest value of current capacity is resulted from improvements in core density, contacting area and grain alignment, etc. In addition the effect of processing variables on microstructural evolution and mechanical property of joined tape will be presented.

  • PDF

Ageing Diagnostics in Oil Transformer for Large Capacity due to Test methods (시험방법에 의한 대용량 유입변압기의 열화진단)

  • Sim, Yoon-Tae;Kim, Wang-Gon;Hong, Jin-Woong
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
    • /
    • /
    • pp.96-99
    • /
    • 2003
  • In this paper, ageing diagnostics in the large capacity oil transformer are investigated. Following items are investigated for the ageing diagnostic in transformer oils (leakage current of sensor, power consumption and temperature of transformer oil). All temperature data are gathered from daily report in the substation. The power consumption of transformer are gathered output report of APIS(Airport Power Information System). Especially, data of sensor leakage current are accumulated from the online diagnostic system for transformer oil. The temperature of transformer oils major change factor was ambient temperature and capacity of power load. The leakage current are change by oil temperature. The leakage current ware not more than 2 [nA] in summer,

  • PDF

A Study on the capacity of shunt type active power filter with a thyristor converter load (싸이리스터 컨버터부하를 가지는 병렬형 능동전력필터 용량에 관한 연구)

  • Park, No-Joong;Joeng, Seung-Gi
    • Proceedings of the KIEE Conference
    • /
    • /
    • pp.2470-2474
    • /
    • 1999
  • The main drawback of parallel type active power filters (APFs) is the large capacity required for harmonic compensation. This paper evaluates the APF capacity requirement for harmonic/reactive power compensation for thyristor converter load. Theoretically achievable maximum power factor under partial load is evaluated. it is shown that the APF capacity can be considerably reduced by deliberately limiting the peak current, while maintaining the filtering performance with an acceptable total harmonic current level. the minimum capacity requirement of APF with current limiting is evaluated as a function of the firing angle of thyristor converter and short circuit ratio(SCR).

  • PDF