• 한국지능시스템학회논문지
• /
• 제17권4호
• /
• pp.534-539
• /
• 2007

본 논문에서는 저압 배선 진단 시스템 개발을 위한 지능형 차단 시스템을 제안한다. 제안된 배선 진단 시스템은 TFDR(Time-Frequency Domain Reflectometry) 알고리즘을 통해 배선이 어떤 상태인지를 보여 주는 시스템이다. 그리고 제안된 진단 시스템으로부터 얻은 신호를 분석하여 이상 종류에 따라 분류하는 시스템을 통해 지능형 차단 시스템을 제안한다. 일반적으로, TFDR을 통해 알아 낼 수 있는 이상의 종류는 damage, open 그리고 short 이다. 각 상황에 대한 효율적인 분류를 위하여 IF-THEN 규칙에 기반 한 분류기가 사용된다. 기존 TFDR이 수행되었던 통신선 케이블의 실험 데이터에 기반 한 실험을 통해 본 제안 내용의 우수성을 보이게 된다.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2008년도 추계학술대회논문집
• /
• pp.84-88
• /
• 2008

The roller bearings play an important role not only sustain radial or axial load of system, but carry out a rotatory movement as a various operating conditions. They happen that incipient faults which were caused by excessive load, manufacturing or assembling process's errors and many other reasons are created. The bearing faults make noise and vibration by a continuous collision of rotatory components, which can lower the quality and stability of auto-transmission. Therefore, it is important to detect the early fault as soon as possible. This paper presents a detecting method for the improvement in quality by developing the program which can be used to analyze and predict the vibrational characteristics caused by roller bearing faults. We completed development of the inspection system of vibration by appling the most efficient detecting methods and verified the system's reliability through experiments.

• 한국소음진동공학회논문집
• /
• 제19권3호
• /
• pp.268-273
• /
• 2009

The roller bearings play an important role not only sustain radial or axial load of system, but carry out a rotatory movement as a various operating conditions. They happen that incipient faults which were caused by excessive load, manufacturing or assembling process's errors and many other reasons are created. The bearing faults make noise and vibration by a continuous collision of rotatory components, which can lower the quality and stability of auto-transmission. Therefore, it is important to detect the early fault as soon as possible. This paper presents a detecting method for the improvement in quality by developing the program which can be used to analyze and predict the vibrational characteristics caused by roller bearing faults. We completed development of the inspection system of vibration by applying the most efficient detecting methods and verified the system's reliability through experiments.

• 제어로봇시스템학회논문지
• /
• 제9권10호
• /
• pp.755-767
• /
• 2003

This paper proposes a robust fault-tolerant control framework for robot manipulators to maintain the required performance and achieve task completion in the presence of both partial joint failures and complete joint failures and uncertainties. In the case of a complete joint failure or free-swinging joint failure causing the complete loss of torque on a joint, a fully-actuated robot manipulator can be viewed as an underactuated robot manipulator. To detect and identify a complete actuator failure, an on-line fault detection operation is also presented. The proposed fault-tolerant control system contains a robust adaptive controller overcoming partial joint failures based on robust adaptive control methodology, an on-line fault detector detecting and identifying complete joint failures, and a robust adaptive controller overcoming partial and complete joint failures, and so eventually it can face and overcome joint failures and uncertainties. Numerical simulations are conducted to validate the proposed robust fault-tolerant control scheme.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2000년도 춘계학술대회 논문집
• /
• pp.336-343
• /
• 2000

This paper proposes the failsafe control logic. which has applied to the voting on the TMR system by using FPGA The self-detection circuit is also designed for detecting a characteristic of fault at TMR system. The fault producing in the self-detection system is largely classified among an intermittent fault, a transient fault and a permanent fault. If it is happened to the permanent fault, the system can be failed. Therefore, it is designed the logic circuit which is not transferred the permanent fault to the system after shut off output. The control logic of the Fail Safe proposed in the paper is required for a circuit integrate of device to minimize the failure happened. Therefore, it makes to design FPGA with modeling of VHDL. The circuit of the Fail Safe of TMR system is able to apply to nuclear system, rail-way system, aerospace and aircraft system which is required for high reliability.

• Journal of Electrical Engineering and Technology
• /
• 제5권1호
• /
• pp.36-44
• /
• 2010

This paper presents the design of an algorithm to detect, identify, and locate faults in radial distribution feeders of Provincial Electricity Authority (PEA). The algorithm consists of three major steps. First, the adaptive algorithm is applied to track/estimate the system electrical parameter, i.e. current phasor, voltage phasor, and impedance. Next process, the impedance rule base is used to detect and identify the type of fault. Finally, the current compensation technique and a geographic information system (GIS) are applied to evaluate a possible fault location. The paper also shows the results from field tests of the automate fault location and illustrates the effectiveness of the proposed fault location scheme.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2001년도 하계학술대회 논문집 A
• /
• pp.488-490
• /
• 2001

It is important to catch or classify fault types by any detecting technique for distribution protection. This paper proposes the technique to classify the fault types using wavelet transform in radial distribution line. Modeling of the radial distribution line is simulated using PSCAD/EMTDC and wavelet transform is performed in the Matlab program.

• 전기학회논문지
• /
• 제56권7호
• /
• pp.1183-1190
• /
• 2007

This paper proposes the improved fault decision algorithm using DWT(Discrete Wavelet Transform) and ANNs for the FRTU(Feeder Remote Terminal Unit) on the feeder in the power distribution system. Generally, the FRTU has the fault decision scheme detecting the phase fault, the ground fault. Especially FRTU has the function for 2000ms. This function doesn't operate FI(Fault Indicator) for the Inrush current generated in switching time. But it has a defect making it impossible for the FI to be operated from the real fault current in inrush restraint time. In such a case, we can not find the fault zone from FI information. Accordingly, the improved fault recognition algorithm is needed to solve this problem. The DWT analysis gives the frequency and time-scale information. The neural network system as a fault recognition was trained to distinguish the inrush current from the fault status by a gradient descent method. In this paper, fault recognition algorithm is improved by using voltage monitoring system, DWT and neural network. All of the data were measured in actual 22.9kV power distribution system.

• 한국산학기술학회논문지
• /
• 제10권10호
• /
• pp.2619-2627
• /
• 2009

비접지 배전계통에서 전체고장의 약 70%를 차지하는 지락고장 발생시에는 지락전류가 작아 검출이 어렵지만 고장상태로 전원 공급을 지속할 경우 사고 파급 및 기기 소손을 유발할 가능성이 있기 때문에 지락고장 처리는 매우 중요하다. 본 논문에서는 GPT(접지형 계기용 변압기, Ground Potential Transformer)에서 감지하는 영상전압 신호를 이용하여 고장선로를 검출하고, 비상시 연계선로를 이용하여 정전구역을 복구하기 위해 평상시 개폐기가 열려 있는 상태로 배전선로 사이를 연결하는 상시개방점을 이동하며 각 구간을 차례로 분리하면서 GPT 신호의 사라짐 여부를 감시하여 고장구간을 검출하는 방법을 제안한다. 고장구간 탐색 시 전체 정전이 없고, 고장구간 검출과 건전구간 복구가 동시에 가능하며 다양한 형태의 배전계통 구성에 적용 가능하다는 점에서 효율적이다. 본 논문에서 제안하는 고장처리 방법을 프로그램으로 개발하여 베트남 배전자동화 시범사업에 적용함으로써 알고리즘 및 프로그램의 적정성을 검증하였다.

• 전기학회논문지
• /
• 제59권1호
• /
• pp.19-25
• /
• 2010

Most faults are single-phase-to-ground fault in ungrounded system. The fault currents of single-phase-to-ground are much smaller than detection thresholds of measurement devices, so detecting single-phase-to-ground faults is difficult and important in ungrounded system. The protection coordination method using SGR(Selective Ground Relay) and OVGR(Overvoltage Ground Relay) is generally used in ungrounded system. But this method only detects fault line and it has the possibility of malfunction. This paper proposed to advanced protection coordination method in ungrounded system. The method just using zero-sequence current can detect fault line, fault phase, fault section at terminal device. The general protection method is used to back up protection. In the case study, the proposed method has been testified in demo system by Matlab/Simulink simulations.