• Title/Summary/Keyword: Large fault

Search Result 672, Processing Time 0.024 seconds

An Effective Fault Analysis Method in Large Scale Power System (대전력계통의 고장해석에 관한 효추적인 계산방법에 관한 연구)

  • Jai-Kil Chung;Gi-Sig Byun
    • The Transactions of the Korean Institute of Electrical Engineers
    • /
    • v.32 no.12
    • /
    • pp.435-440
    • /
    • 1983
  • The methods of forming the bus impedance matrix, which is mainly employed in fault analysis of power system, can be generally classified in catagories, (1) the one being the inverse matrix of bus admittance matrix, and (2) the other the bus impedance matrix succesive formation method by particular algorithms. The former method is theouetically elegant, but the formation and inverse of complex bus admittance matrix for large power system requires too much amounts of computer memory space and computing time. The latter method also requires too much memory space. Therefore, in this paper, an algorithm and computer program is introduced for the formation of a sparse bus impedance matrix which generates only the matching terms of the admittance matrix. So, this method can reduce the computer memory and computing time, and can be applied to fault analysis of large power system by small digital computer.

Simulation for Voltage Variations of a Grid-connected Wind Turbine Generation System by Simulink (Simulink에서 계통연계 풍력발전시스템의 전압변동 시뮬레이션)

  • Ahn Duck-Keun;Ro Kyoung-Soo
    • The Transactions of the Korean Institute of Electrical Engineers A
    • /
    • v.53 no.11
    • /
    • pp.589-595
    • /
    • 2004
  • This paper presents a modeling and simulation of a grid-connected wind turbine generation system with respect to wind variations, starting of large induction motor and three-phase fault in the system, and investigates voltage variations of the system for disturbances. It describes the modeling of the wind turbine system including the drive train model, induction generator model, and grid-interface model on MATLAB/Simulink. The simulation results show the variation of the generator torque, the generator rotor speed, the pitch angle, terminal voltage, system voltage, fault current, and real/reactive power output, etc. Case studies demonstrate that the pitch angle control is carried out to achieve maximum power extraction for wind speed variations, starting of a large induction motor causes a voltage sag due to a large starting current, and a fault on the system influences on the output of the wind turbine generator.

An Application-Level Fault Tolerant System For Synchronous Parallel Computation (동기 병렬연산을 위한 응용수준의 결함 내성 연산시스템)

  • Park, Pil-Seong
    • Journal of Internet Computing and Services
    • /
    • v.9 no.5
    • /
    • pp.185-193
    • /
    • 2008
  • An MTBF(mean time between failures) of large scale parallel systems is known to be only an order of several hours, and large computations sometimes result in a waste of huge amount of CPU time, However. the MPI(Message Passing Interface), a de facto standard for message passing parallel programming, suggests no possibility to handle such a problem. In this paper, we propose an application-level fault tolerant computation system, purely on the basis of the current MPI standard without using any non-standard fault tolerant MPI library, that can be used for general scientific synchronous parallel computation.

  • PDF

A Novel Online Multi-section Weighed Fault Matching and Detecting Algorithm Based on Wide-area Information

  • Tong, Xiaoyang;Lian, Wenchao;Wang, Hongbin
    • Journal of Electrical Engineering and Technology
    • /
    • v.12 no.6
    • /
    • pp.2118-2126
    • /
    • 2017
  • The large-scale power system blackouts have indicated that conventional protection relays that based on local signals cannot fit for modern power grids with complicated setting or heavily loaded-flow transfer. In order to accurately detect various faulted lines and improve the fault-tolerance of wide-area protection, a novel multi-section weighed fault matching and detecting algorithm is proposed. The real protection vector (RPV) and expected section protection vectors (ESPVs) for five fault sections are constructed respectively. The function of multi-section weighed fault matching is established to calculate the section fault matching degrees between RPV and five ESPVs. Then the fault degree of protected line based on five section fault degrees can be obtained. Two fault detecting criterions are given to support the higher accuracy rate of detecting fault. With the enumerating method, the simulation tests illustrate the correctness and fault-tolerance of proposed algorithm. It can reach the target of 100% accuracy rate under 5 bits error of wide-area protections. The influence factors of fault-tolerance are analyzed, which include the choosing of wide-area protections, as well as the topological structures of power grid and fault threshold.

A Study on the Measurement of End Bearing Capacity for Large Diameter Drilled Shaft Constructed in Fault Zone Using the Static Bi-directional End Leading Test (양방향 선단재하시험을 이용한 단층파쇄대에 시공된 대구경 현장타설말뚝의 선단지지력 측정 연구)

  • 정창규;정성민;황근배;최용규
    • Journal of the Korean Geotechnical Society
    • /
    • v.20 no.5
    • /
    • pp.135-143
    • /
    • 2004
  • In the land section of marine bridge construction site, to confirm the end bearing of large diameter drilled shaft constructed in the fault zone which was discovered unexpectedly, the hi-directional end loading tests were performed. The objectives of this study are to confirm the end bearing of the pile constructed in fault zone and the increasing effect of end bearing after grouting the base ground beneath the pile toe. After grouting the pile base ground, the settlement of pile base decreased considerably and the pile base resistance increased more than twice.

A Case Study of Collapse and Reinforcement for Large Span Waterway Tunnel at Thrust Fault Zone (스러스트 단층대에서의 대단면 수로터널 낙반 및 보강 사례)

  • Kim, Young-Geun;Han, Byeong-Hyun;Lee, Seung-Bok;Kim, Eung-Tae
    • Tunnel and Underground Space
    • /
    • v.21 no.4
    • /
    • pp.251-263
    • /
    • 2011
  • The geomechanical characteristics of rock and the structural geological feature of the fault should be studied and examined for the successful construction of large-span tunnel. In this case study, that is a important case for the tunnel collapse and reinforcement during the construction for the waterway tunnel at large thrust fault zone in schist, we carried out geological and geotechnical survey for make the cause and mechanism of tunnel collapse. Also, we have designed the reinforcement and re-excavation for the safe construction for collapse zone and have carried out successfully the re-excavation and finished the final concrete lining.

Arc Extinguishment for Low-voltage DC (LVDC) Circuit Breaker by PPTC Device (PPTC 소자를 사용한 저전압 직류차단기의 아크소호기술)

  • Kim, Yong-Jung;Na, Jeaho;Kim, Hyosung
    • The Transactions of the Korean Institute of Power Electronics
    • /
    • v.23 no.5
    • /
    • pp.299-304
    • /
    • 2018
  • An ideal circuit breaker should supply electric power to loads without losses in a conduction state and completely isolate the load from the power source by providing insulation strength in a break state. Fault current is relatively easy to break in an Alternating Current (AC) circuit breaker because the AC current becomes zero at every half cycle. However, fault current in DC circuit breaker (DCCB) should be reduced by generating a high arc voltage at the breaker contact point. Large fire may occur if the DCCB does not take sufficient arc voltage and allows the continuous flow of the arc fault current with high temperature. A semiconductor circuit breaker with a power electronic device has many advantages. These advantages include quick breaking time, lack of arc generation, and lower noise than mechanical circuit breakers. However, a large load capacity cannot be applied because of large conduction loss. An extinguishing technology of DCCB with polymeric positive temperature coefficient (PPTC) device is proposed and evaluated through experiments in this study to take advantage of low conduction loss of mechanical circuit breaker and arcless breaking characteristic of semiconductor devices.

Current Limiting Characteristics of a SFCL with Two Triggered Current Limiting Levels in a Simulated Power Distribution System (모의배전계통에 두 트리거 전류레벨을 이용한 초전도한류기의 전류제한 특성 분석)

  • Ko, Seok-Cheol;Han, Tae-Hee
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
    • /
    • v.26 no.2
    • /
    • pp.134-139
    • /
    • 2013
  • When the accident occurred in power distribution system, it needs to control efficiently the fault current according to the fault angle and location. The flux-lock type superconducting fault current limiters (SFCL) can quickly limit when the short circuit accidents occurred and be made the resistance after the fault current. The flux-lock type SFCL has a single triggering element, detects and limits the fault current at the same time regardless of the size of the fault current. However, it has a disadvantage that broken the superconductor element. If the flux-lock type SFCL has separated structure of the triggering element and the limiting element, when large fault current occurs, it can reduce the burden of power and control fault current to adjust impedance. In this paper, this system is composed by triggering element and limiting element to analyze operation of limiting current. When the fault current occurs, we analyzed the limiting and operating current characteristics of the two triggering current level, and the compensation characteristics of bus-voltage sag according to the fault angle and location.

Hybrid Type Superconducting Fault Current Limiter Modeling using EMTP (EMTP를 이용한 Hybrid Type Superconducting Fault Current Limiter)

  • Park, Se-Ho;Rhee, Sang-Bong
    • Proceedings of the KIEE Conference
    • /
    • 2008.11a
    • /
    • pp.172-174
    • /
    • 2008
  • A fault current limitation using fault current limiter(FCL) is very important for power system operation. In recent year, a number of research have been performed and still Progressing about the super conducting fault current limiter(SFCL), To protect the power system effectively from the large fault current, several superconducting fault current limiters proposed. However, there are many problem such as cost, recovery and ac loss. To solve these problems, hybrid superconducting fault current limiter(HSFCL) have been proposed. In this paper, HSFCL are modeled using (Electro Magnetic Transient Program - Restructured Version) EMTP-RV.

  • PDF

Analysis on the Protective Coordination with Hybrid Superconducting Fault Current Limiter (반주기 이후 동작 하이브리드 초전도 전류제한기와 보호기기 협조 분석)

  • Kim, Jin-Seok;Lim, Sung-Hun;Kim, Jae-Chul;Choi, Jong-Soo
    • The Transactions of The Korean Institute of Electrical Engineers
    • /
    • v.60 no.10
    • /
    • pp.1832-1837
    • /
    • 2011
  • The fault current has increased due to the large power demand in power distribution system and network distribution system. To protect the power system effectively from the increased fault current, the superconducting fault current limiter (SFCL) has been notified. However, the conventional SFCL has some problems such as cost, operation, recovery, loss. To solve some problems, the hybrid superconducting fault current limiter using the fast switch was proposed. However, hybrid SFCL also has a problem that is protection coordination in power distribution system with hybrid SFCL. In this paper, the fault current limiting characteristics of hybrid SFCL with first half cycle non-limiting operation according to the fault angle, the resistance of superconducting element, and the magnitude of Current Limit Resistor (CLR) which are the components of hybrid SFCL were analyzed through the experiments.