• 센서학회지
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• 제10권1호
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• pp.33-41
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• 2001

와이어 로프는 무거운 중량을 안전하게 운반하거나 기계적인 에너지를 빠르게 전송하는 곳과 같은 산업응용 분야에 광범위하게 사용되어 왔다. 특히, 운전 중 엘리베이터의 와이어 로프가 파손되면 큰 재산 상 손실과 주변 인명의 심각한 상해를 초래할 수 있다. 따라서, 와이어 로프의 정기적인 검사는 매우 중요하다. 와이어 로프의 고장 검출은 로프의 구조, 특성, 결함 특성, 검출방법과 신호처리 방법에 대한 기본적인 이해가 요구된다. 이 연구에서는 엘리베이터에 노화된 와이어 로프에 대한 마모, 단선, 부식과 형붕괴와 같은 결함을 검출하기 위하여, Hall 센서를 결합한 새로운 결함 검출시스템의 개발에 대하여 다룬다. 휴대용 계측기로서 검출기를 사용하기 위하여, Hall 센서를 가진 센싱 부분과 아날로그 신호처리 및 프로그램의 제작에 대한 몇 가지 특성들이 서술되었다. 제작된 검출시스템에 대한 실험과 실장시험 결과 역시 제시되었다. 그 결과, 검출시스템은 사용 중인 노화된 와이어 로프의 결함을 검출하는데 양호한 효율성을 갖는다는 것을 확인하였다.

• 대한안전경영과학회지
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• 제24권4호
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• pp.1-8
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• 2022

Elevators are the main means of transport in buildings. A malfunction of an elevator in operation may cause in convenience to users. Furthermore, fatal accidents, such as injuries and death, may occur to the passengers also. Therefore, it is important to prevent failure before accidents happen. In related studies, preventive measures are proposed through analyzing failures, and the lifespan of elevator components. However, these methods are limited to existing an elevator model and its surroundings, including operating conditions and installed environments. Vibration occurs when the elevator is operated. Experts have classified types of faults, which are symptoms for malfunctions (failures), via analyzing vibration. This study proposes an artificial intelligent model for classifying faults automatically with deep learning algorithms through elevator vibration data, hereby preventing failures before they occur. In this study, the vibration data of six elevators are collected. The proposed methodology in this paper removes "the measurement error data" with incorrect measurements and extracts operating sections from the input datasets for proceeding deep learning models. As a result of comparing the performance of training five deep learning models, the maximum performance indicates Accuracy 97% and F1 Score 97%, respectively. This paper presents an artificial intelligent model for detecting elevator fault automatically. The users' safety and convenience may increase by detecting fault prior to the fatal malfunctions. In addition, it is possible to reduce manpower and time by assisting experts who have previously classified faults.

• 전자공학회논문지SC
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• 제47권5호
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• pp.9-17
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• 2010

교정 제어는 비동기 순차 머신의 안정 상태 동작을 원하는 목적에 맞게 바꾸어주는 역할을 한다. 본 논문에서는 교정 제어를 이용하여 영구 고장이 존재하는 비동기 순차 머신의 고장 극복 기법을 제안한다. 비동기 순차 머신에서 영구 고장이 발생하면 머신은 원래 상태로 영원히 회복되지 못하고 제한된 상태 집합 내에서만 동작하게 된다. 하지만 비동기 순차 머신이 줄어든 작동 범위 안에서도 정상적인 동작을 계속할 수 있는 여유도를 가지고 있다면 교정 제어 기법을 이용하여 고장 극복 문제를 해결할 수 있다. 본 논문에서는 영구 고장을 탐지할 수 있는 조건과 함께 고장 극복 문제를 푸는 교정 제어기가 존재할 필요충분조건을 밝힌다. 또한 사례 연구를 통해서 제안된 제어기의 설계 과정을 예시한다.

• Journal of Magnetics
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• 제18권2호
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• pp.135-141
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• 2013

This paper proposes an efficient fault detection method for onboard degaussing coils which are installed to minimize underwater magnetic fields due to the ferromagnetic hull. To achieve this, the method basically uses field signals measured at specific magnetic treatment facilities instead of time-consuming numerical field solutions in a three-dimensional analysis space. In addition, an analytical design sensitivity formula and the linear property of degaussing coil fields is being exploited for detecting fault coil positions and assessing individual degaussing coil currents. Such peculiar features make it possible to yield fast and accurate results on the fault detection of degaussing coils. For foreseeable fault conditions, the proposed method is tested with a model ship equipped with 20 degaussing coils.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1987년도 정기총회 및 창립40주년기념 학술대회 학회본부
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• pp.454-456
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• 1987

A more specialized area of transient evaluations is transmission line fault-detecting and protection system. During the first cycle or two following a power system fault, a high-speed protective relay is expected to make a decision as to the severity or location of the fault, usually based on 60 Hz information, i.e. the phase and magnitude of 60 Hz voltage or current signals. It is precisely at this time however that the signal is badly corrupted by noise, in the form of a de offset or frequencies above 50 Hz. One of several possible sources of transients in protection measuring signals is in the primary system for which protection is required in its response to the impact of short circuit fault on-set. Other sources are in the primary voltage and current transducers from which protection signals are derived, and, often of particular importance, in the interface circuits between the transducer secondaries and the comparator and measuring elements of the protection system. However, the noise signals that will be described in this paper are due to the main power system only and do not include errors due to current or voltage transducers.

• 대한전기학회논문지:전력기술부문A
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• 제48권11호
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• pp.1388-1393
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• 1999

A more reliable algorithm for detecting a high impedance fault (HIF) requires fault currents at the relaying point containing information of load condition as well as HIF characteristics. This paper presents a modeling method of an HIF in a distribution system using EMTP. From the voltage and current waveforms of HIF experiment, the voltage-current characteristic is obtained and then piecewise linearized. The proposed method gets several points on the linearized voltage-current curve and then represents nonlinearity as piecewise linear resistances using Transient Analysis of Control Systems (TACS) in EMTP. Thus, an HIF is represented as a voltage source in the first and third quadrants of voltage-current plane. The method is implemented in EMTP and thus the voltage and current at the relaying point can be obtained when an HIF occurs. In this paper, an HIF was simulated on various load conditions and fault conditions in 22.9 [kV] distribution systems.

• 조명전기설비학회논문지
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• 제29권11호
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• pp.89-95
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• 2015

As a solution of improving the energy efficiency in power system, Low Voltage DC (LVDC) distribution systems different from conventional ones have been constantly researched. As in conventional AC distribution system, LVDC distribution system can suffer from High Impedance Fault (HIF) which may cause a failure of protective relay due to relatively low change in magnitude of fault current. In order to solve the problem, a scheme for detecting HIFs is presented in this paper. Closing Opening Difference Operation (CODO) based on Mathematical Morphology (MM), one of the MM-based filters, is utilized to make fault signals discriminable. To verify performance of the scheme, a simple LVDC distribution system is modeled by using ElectroMagnetic Transient Program (EMTP) software. Computer simulations according to various conditions are performed and comparison studies with a scheme using Wavelet Transform (WT) in an aspect of simulation time are also conducted.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1987년도 정기총회 및 창립40주년기념 학술대회 학회본부
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• pp.449-453
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• 1987

This paper presents the detecting algorithm of inrush current which causes protective equipment to maloperate in energizing a power distribution line. This detecting algorithm uses the method which extracts the decay component and energy of 2nd harmonics by Prony Spectral Estimation Method existed AR model to new ARMA model. In this paper, the inrush currents are obtained by model simulations and fild tests. By applying these data to the detecting algorithm, it has been confirmed to discriminate inrush currents from fault currents.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2001년도 전력전자학술대회 논문집
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• pp.543-547
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• 2001

A protection scheme for Unified Power Quality Conditioner (UPQC) is presented and analyzed in this paper. The proposed UPQC has the series active power filter operated as a high impedance k($\Omega$) to the fundamentals when short-circuit faults occur in the power distribution system, and three control strategies are proposed in this paper. The first is the method by detecting the fundamental source current through the p-q theory, the second is the method by detecting the fundamental component of load current in Synchronous Reference Frame(SRF) and the third is the method by detecting the input voltage. When the short-circuit fault occur in the power distribution system, the proposed scheme protects the UPQC without additional protection circuits. The validity of proposed protection scheme is investigated through simulation results.

• 전기의세계
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• 제25권4호
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• pp.59-62
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• 1976

This study on the characteristics of the leakage circuit breakers handles the rolls of each itemized parts of the mentioned apparatus and their influence in determining of the characteristic curve of leakage circuit breaker. Furthermore the differential current transforms in the mentioned apparatus for detecting the fault is handled as a heavy point.