• KIEE International Transactions on Power Engineering
• /
• 제4A권1호
• /
• pp.26-32
• /
• 2004

Digital technology has advanced significantly over the years both in terms of software tools and hardware availability. It is now applied extensively throughout many area of electrical engineering including protective relaying in power systems. Digital relays have numerous advantages over traditional analog relays, such as the ability to accomplish what is difficult or impossible using analog relays. Although non real-time simulators like PSCAD/EMTDC are employed to test the algorithms, such simulations are disadvantaged in that they cannot test the relay dynamically. Hence, real-time simulators like RTDS are used. However, the latter requires large space and is very expensive. This paper uses EMTP MODELS to simulate the power system and the distance relay. The distance relay algorithm is implemented and the distance relay is interfaced with a test power system. The distance relay's performance is then assessed interactively under various fault types, fault distances and fault inception angles. The test results show that we can simulate the distance relay effectively and we can examine the operation of the distance relay very closely including its drawbacks/limitations by using EMTP MODELS. Equally important, this approach facilitates any changes that need to be carried out in order to enhance the Distance Relay under test/examination.

• 전기학회논문지
• /
• 제57권12호
• /
• pp.2139-2146
• /
• 2008

This paper presents a numerical algorithm for fault location estimation which used to data from both end of the transmission line. The proposed algorithm is also based on the synchronized voltage and current phasor measured from the PMUs(Phasor Measurement Units) in the time-domain. This paper has separated from two part of with/without shunt capacitance(short/long distance). Most fault was arc one-ground fault which is 75% over [1]. so most study focused with it. In this paper, the numerical algorithm has calculated to distance for ground fault and line-line fault. In this paper, the algorithm is given with/without shunt capacitance using II parameter line model, simple impedance model and estimated using DFT(Discrete Fourier Transform) and the LES(Least Error Squares Method). To verify the validity of the proposed algorithm, the EMTP(Electro- Magnetic Transient Program) and MATLAB did used.

• 한국항행학회논문지
• /
• 제11권3호
• /
• pp.313-318
• /
• 2007

본 논문은 FDA(Fault Detection Agent)의 설계와 구축을 설명한다. FDA는 홈 네트워크 환경에서 멀티미디어 원격 교육을 위한 소프트웨어 오류를 감지하기에 적합한 에이전트이다. 이 시스템은 ED, ES로 구성되어 있다. ED는 홈 네트워크 환경에서 멀티미디어 원격 교육을 위하여 훅 킹 기법으로 오류를 감지하는 에이전트이다. ES는 홈 네트워크 환경에서 멀티미디어 원격 교육을 위하여 오류를 공유하는 에이전트이다. 멀티미디어 공동 작업 환경의 관점에서 오류 공유는 협동 작업에 참가하는 참가자에게 상호작용적으로 오류를 공유한다. 훅 킹 방법과 가로채기 방법과의 비교를 통하여 효율성 분석을 하였다.

• Journal of Electrical Engineering and Technology
• /
• 제8권3호
• /
• pp.499-506
• /
• 2013

The accurate estimation of a fault location is desired in distance protection schemes for transmission lines in order to selectively deactivate a faulted line. However, a typical method to estimate a fault location by calculating impedances with voltages and currents at relaying points may have errors due to various factors such as the mutual impedances of lines, fault impedances, or effects of parallel circuits. The proposed algorithm in this paper begins by extracting the fundamental phasor of the positive sequence currents from the three phase currents. The second-order difference of the phasor is then calculated based on the fundamental phasor of positive sequence currents. The traveling times of the waves generated by a fault are derived from the second-order difference of the phasor. Finally, the distance from the relaying point to the fault is estimated using the traveling times. To analyze the performance of the algorithm, a power system with EHV(Extra High Voltage) untransposed double-circuit transmission lines is modeled and simulated under various fault conditions, such as several fault types, fault locations, and fault inception angles. The results of the simulations show that the proposed algorithm has the capability to estimate the fault locations with high speed and accuracy.

• 대한전기학회논문지:전력기술부문A
• /
• 제52권1호
• /
• pp.17-28
• /
• 2003

Digital technology has advanced very significantly over the years both in terms of software tools and hardware available. It is now applied extensively in many area of electrical engineering including protective relaying in power systems. Digital relays based on digital technology have many advantages over the traditional analog relays. The digital relay is able to do what is difficult or impossible in the analog relays. However, the complex algorithms associated with the digital relays are difficult to test and verify in real time on real power systems. Although non real-time simulators like PSCAD/EMTDC are employed to test the algorithms, such simulations have the disadvantage that they cannot test the relay dynamically. Hence, real-time simulators like RTDS are used, but the latter needs large space and it is very expensive. This paper uses EMTP MODELS to simulate the power system and the distance relay. The distance relay algorithm is constructed and the distance relay is interfaced with a test power system. The distance relays performance is then assessed interactively under various fault types, fault distances and fault inception angles. The test results show that we can simulate the distance relay effectively and we can examine the operation of the distance relay very closely including debugging by using EMTP MODELS.

• 한국지능시스템학회논문지
• /
• 제8권2호
• /
• pp.9-20
• /
• 1998

본 논문에서는 패턴인식 형태로 구성된 거리계전시스템에 신경회로망을 적용한 새로운 형태의거리계전기법이 제시되었다. 제안된 거리계전기법은 패턴인식 단계인 두개의 블록으로 구성되었다. 첫 단계에서는 과도신호의 특징 파라미터인 기본파성분을 효율적으로 추출하기 위해 신경회로망을 이용한 필터링 방법이 적용되었으며, 두번째 단계에서는 첫단계에서 추출된 기본파성분을 입력으로 고장형태를 신속하고 정확하게 판별 분류 될 수 있도록 신경회로망을 이용한 고장패턴 추정기가 개발적용되었으며, 이울러 고장판별에 따라 고장점을 효율적으로 추정될 수 있도록 하였다. 적용 시스템의 각 단계는 함수 근사화, 보간성능 및 패턴분류 등의 능력이 뛰어난 다층 퍼셉트론의 역전파 학습 알고리즘이 적용되었다. 제신된 기법의 성능을 입증하기 위하여 EMTP 시뮬레이션을 하여 얻은 다양한 과도 고장파형의 계전시호를 활용하여 시험하였으며, 그결과 제시된 기법은 학습되지 않은 임의의 패턴에 대하여 적응성을 가지고 효율적으로 고장점이 추정될 수 있었으며, 고장발생후 3샘플 이내에서 고장형태가 신속하고도 정확하게 판별되었다.

• 자원환경지질
• /
• 제32권4호
• /
• pp.365-371
• /
• 1999

Ture diplacement of a fault monement is calculated from the displacement of the index plane such as bedding on an outcrop surface. The input parameters are the orientations of the index, fault, and outcrop planes. It is also necessary to input the orientation of fault striation and the offset distance of the index plane on the outcrop surface. The distances of the total, strike, horizontal and dip slip components of the fault movement are calculated from the input parameters. Hwang(1998) conducted a simlar calculation using trigonoment method. To apply the previous method, the offset distance of the index plane must be measured on a vertical outcrop surface. The calculation method of this study accepts the offset distence of index plane on an outcrop plane of any orientation. Calculation results from both method are indentical, regardless of the simplicity of the new method.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2006년도 제37회 하계학술대회 논문집 A
• /
• pp.167-168
• /
• 2006

This paper proposes a new fault distance calculation method in the power quality (PQ) monitoring system. The proposed method calculates the fault impedance and the fault distance based on the measurement data of the PQ monitors and the information of the topology of the distribution systems. By using the iterative calculation method, the proposed method can find more exact location of the PQ events than the existing methods. The proposed method is applied to the IEEE 34 bus test feeders by using the PSCAD/EMTDC$^{TM}$.

• 대한전기학회논문지
• /
• 제40권12호
• /
• pp.1203-1210
• /
• 1991

This paper proposes a new distance relaying method based on fault initiated travelling waves for transmission line protection. The characteristics of this method are ultra high speed and excellent sensitivity. Travelling wave technique which is one of the distance relaying methods uses the discrete cross correlation function for discrimination between internal and external fault is remarkably reduced in case of a close up fault and an inception angle near or equal to zero fault. To cope with this problem, a new fast algorithm which uses backward wave summation method with fixed window is presented. The proposed method has been tested by numerical simulations using the EMTP.

• Journal of Electrical Engineering and Technology
• /
• 제12권2호
• /
• pp.533-540
• /
• 2017

Distance relay identifies the type and location of fault by measuring the transmission line impedance. However any other factors that cause miss calculating the measured impedance, makes the relay detect the fault in incorrect location or do not detect the fault at all. One of the important factors which directly changes the measured impedance by the relay is series capacitive compensation (SCC). Another factor that changes the calculated impedance by distance relay is fault resistance. This paper provides a method based on the combination of distance and differential protection. At first, faulty transmission line is detected according to the current data of buses. After that the fault location is calculated using the proposed algorithm on the transmission line. This algorithm is based on active power calculation of the buses. Fault resistance is calculated from the active powers and its effect will be deducted from calculated impedance by the algorithm. This method measures the voltage across SCC by phasor measurement units (PMUs) and transmits them to the relay location via communication channels. The transmitted signals are utilized to modify the voltage signal which is measured by the relay. Different operating modes of SCC and as well as different faults such as phase-to-phase and phase-to-ground faults are examined by simulations.