• Title/Summary/Keyword: Internal fault

Search Result 248, Processing Time 0.041 seconds

Feature Extraction of Partial Discharge for Stator Winding of High Voltage Motor (고압전동기 고정자권선의 부분방전 특징추출)

  • Park, Jae-Jun;Kim, Hee-Dong;Lee, Dong-Yoon
    • Proceedings of the KIEE Conference
    • /
    • 2004.11a
    • /
    • pp.112-116
    • /
    • 2004
  • On-line monitoring of fault discharge is an important approach for indicating the condition of electrical insulation of stator winding in high voltage motor. In this paper, several key aspects of on-line monitoring system are discussed, involving the characteristics of fault discharge of stator winding in high voltage motor, spectrum analysis of four simulation fault signals, feature extraction of internal fault discharge from apply voltage to breakdown. The study of the partial discharge activities allows to highlight the ageing stage in the winding fault under test. During the life of the winding insulation fault, the shape of PD signal change relating to the ageing stage. The ageing of stator winding insulation fault of high voltage motor is investigated based on the characteristics of partial discharge pulse distribution and statistical parameters, such as maximum, skewness and kurtosis using discrete wavelet transform coefficients.

  • PDF

A Protection Algorithm Discriminating Between Internal and External Faults for Wind Farms (풍력발전단지 보호를 위한 내외부 고장 판별 알고리즘)

  • Kwon, Young-Jin;Kang, Sang-Hee
    • The Transactions of The Korean Institute of Electrical Engineers
    • /
    • v.56 no.5
    • /
    • pp.854-859
    • /
    • 2007
  • A wind farm consists of many wind generator(WG)s therefore, it is generally a complex power system. A wind farm as a distributed generation(DG) affects utility power system. If a conventional protection schemes are applied, it is difficult to detect faults correctly and the schemes can't provide proper coordination in some cases. This paper presents a protection algorithm for a wind farm which consists of a looped collection circuit. Because the proposed algorithm can distinguish between an internal fault and an external fault in a wind farm, The proposed algorithm can disconnect the faulted section in a wind farm. This algorithm is based on an overcurrent protection technique with the change of the ratio of the output current of a generator to the current of the looped line connected to each generator to collect the each generator's power. In addition, operating time of the algorithm is shortened by using the voltage drop at a generator collection point. The performance of the proposed algorithm was verified under various fault conditions using PSCAD/EMTDC simulations.

Fault Current Analysis of HTS Power Cable (고장전류에 의한 초전도 전력케이블의 내부전류 변화 분석)

  • Bang, Jong-Hyun;Je, Hyang-Ho;Kim, Jae-Ho;Sim, Ki-Deok;Cho, Jeon-Wook;Yoon, Jae-Young;Jang, Hyun-Man;Lee, Su-Kil;Park, Min-Won;Yu, In-Keun
    • Proceedings of the KIEE Conference
    • /
    • 2006.07a
    • /
    • pp.290-291
    • /
    • 2006
  • HTS(High Temperature Superconductivity) Power Cable has a different characteristic with conventional distribution line, so installation and operation condition are different. In this paper, internal fault current characteristic s of HTS power cable was analyzed. For this, EMTDC model component of HTS power cable was developed. The developed EMTDC model component is applied to distribution line, then authors analyze internal current characteristics of HTS Power cable when fault occurred.

  • PDF

The new protective relaying scheme of power transformer using wavelet transforms (웨이브렛 변환을 이용한 새로운 변압기 보호계전 방식)

  • Kwon, G.B.;Suh, H.S.;Yoon, S.M.;Shin, M.C.
    • Proceedings of the KIEE Conference
    • /
    • 2002.07a
    • /
    • pp.199-202
    • /
    • 2002
  • This paper presents the new protective relaying scheme as a method for discriminating of power transform's transient state associated with magnetizng inrush state and internal fault using wavelet transforms. The simulation of EMTP with respect to different fault and inrush condition in transformer have been conducted, and the result prove that the preposed method is able to discriminate between inrush magnetizing current and internal fault.

  • PDF

Power Transformer Modeling and Transient Analysis using PSCAD (PSCAD를 이용한 전력용 변압기 모델링과 과도 해석)

  • Park, Chul-Won
    • The Transactions of the Korean Institute of Electrical Engineers P
    • /
    • v.65 no.2
    • /
    • pp.122-129
    • /
    • 2016
  • Current differential protection relaying with second harmonic restraint is the main protection for large capacity power transformer. PSCAD simulation program is widely used for modeling of dynamic varying transients phenomena. This paper deals with a power transformer model and transients analysis using PSCAD software to develop IED for power transformer. Simulation was carried out using a three phase 40MVA, 154/22.9kV, 60Hz, two-winding transformer with Y-Y connection used in actual fields. The paper analyzed transformer magnetizing inrush, external fault, and internal fault conditions with this model in the time domain. In addition, we performed an analysis in the frequency domain using FFT during several conditions.

The protective relaying scheme of power transformer using wavelet based neural networks (웨이브렛 변환을 바탕으로 한 신경회로망을 이용한 전력용 변압기 보호 계전기법)

  • Kweon, G.B.;Yoon, S.M.;Shin, M.C.
    • Proceedings of the KIEE Conference
    • /
    • 2001.07a
    • /
    • pp.229-232
    • /
    • 2001
  • This paper presents the protective relaying scheme as a method for discriminating of power transform's transient state associated with magnetizng inrush state, over-exciting state and internal fault using wavelet based neural networs. The simulation of EMTP with respect to different fault, inrush condition and over-exciting condition in transformer have been conducted, and the result prove that the proposed method is able to discriminate between inrush magnetizing current and internal fault.

  • PDF

Synthesis of the Fault-Causality Graph Model for Fault Diagnosis in Chemical Processes Based On Role-Behavior Modeling (역할-거동 모델링에 기반한 화학공정 이상 진단을 위한 이상-인과 그래프 모델의 합성)

  • 이동언;어수영;윤인섭
    • Journal of Institute of Control, Robotics and Systems
    • /
    • v.10 no.5
    • /
    • pp.450-457
    • /
    • 2004
  • In this research, the automatic synthesis of knowledge models is proposed. which are the basis of the methods using qualitative models adapted widely in fault diagnosis and hazard evaluation of chemical processes. To provide an easy and fast way to construct accurate causal model of the target process, the Role-Behavior modeling method is developed to represent the knowledge of modularized process units. In this modeling method, Fault-Behavior model and Structure-Role model present the relationship of the internal behaviors and faults in the process units and the relationship between process units respectively. Through the multiple modeling techniques, the knowledge is separated into what is independent of process and dependent on process to provide the extensibility and portability in model building, and possibility in the automatic synthesis. By taking advantage of the Role-Behavior Model, an algorithm is proposed to synthesize the plant-wide causal model, Fault-Causality Graph (FCG) from specific Fault-Behavior models of the each unit process, which are derived from generic Fault-Behavior models and Structure-Role model. To validate the proposed modeling method and algorithm, a system for building FCG model is developed on G2, an expert system development tool. Case study such as CSTR with recycle using the developed system showed that the proposed method and algorithm were remarkably effective in synthesizing the causal knowledge models for diagnosis of chemical processes.

Fault Detection of the Control System Based on Multiprocessors (다중 프로세서를 이용한 제어 시스템에서의 자체고장탐지)

  • ;;;;Zeung Nam Bien
    • Journal of the Korean Institute of Telematics and Electronics
    • /
    • v.25 no.8
    • /
    • pp.906-915
    • /
    • 1988
  • The reliability enhancement is the critical issue in many computer applications, particulary in process control system. In this paper we describe how to achieve the reliability improvement in control system which is based on multiprocessors. The proposed method is accomplished by using the techniques of fault detection which composed by internal and external fault detections, fault isolation for removing the fault propagation, safety action for driving safe input, and fault diagnosis. This approach is experimented and asopted in boiler backup control system constructed by VMEbus system, CPU boards, graphic system, and other interface boards with UNIX operating system.

  • PDF

Advanced Algorithm for IED of Stator Winding Protection of Generator System (발전기시스템의 고정자보호 IED를 위한 개선된 알고리즘)

  • Park, Chul-Won
    • The Transactions of the Korean Institute of Electrical Engineers P
    • /
    • v.57 no.2
    • /
    • pp.91-95
    • /
    • 2008
  • The large AC generator fault may lead to large impacts or perturbations in power system. The generator protection control systems in Korea have been imported and operated through a turn-key from overseas entirely. Therefore a study of the generator protection field has in urgent need for a stable operation of the imported goods. In present, the algorithm using the current ratio differential relaying based DFT for stator winding protection or a fault detection had been applied that of internal fault protection of a generator. the DFT used for the analysis of transient state signal conventionally had defects losing a time information in the course of transforming a target signal to frequency domain. In this paper, the discrete wavelet transform (DWT) was applied a fault detection of the generator being superior to a transient state signal analysis and being easy to real time realization. The fault signals after executing a terminal fault modeling collect using a MATLAB package, and calculate the wavelet coefficients through the process of a muiti-level decomposition (MLD). The proposed algorithm for a fault detection using the Daubechies WT (wavelet transform) was executed with a C language and the commend line function for the real time realization after analyzing MATLAB's graphical interface. The advanced technique had improved faster a speed of fault discrimination than a conventional DFR based on DFT.

Advanced Protective Relaying Algorithm by Flux-Differential Current Slope Characteristic for Power Transformer (전력용 변압기용 자속-차전류 기울기 특성에 의한 개선된 보호계전 알고리즘)

  • 박철원;신명철
    • The Transactions of the Korean Institute of Electrical Engineers A
    • /
    • v.53 no.7
    • /
    • pp.382-388
    • /
    • 2004
  • The most widely used primary protection for the internal fault detection of power transformers is current percentage differential relaying(PDR). However, the harmonic components could be decreased by magnetizing inrush when there have been changes to the material of iron core or its design methodology. The higher the capacitance of high voltage status and underground distribution, the more differential current includes the second harmonic component during occurrence of an internal fault. Therefore, the conventional harmonic restraint methods need modification. This paper proposes an advanced protective relaying algorithm by fluxt-differential current slope characteristic and trend of voltage and differential current. To evaluate the performance of proposed algorithm, we have made comparative studies of PDR fuzzy relaying, and DWT relaying. The paper is constructed power system model including power transformer, utilizing the WatATP99, and data collection is made through simulation of various internal faults and inrush. As the results of test. the new proposed algorithm was proven to be faster and more reliable.