• Journal of the Korean Society for Precision Engineering
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• v.20 no.1
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• pp.99-106
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• 2003

Uninterrupted power supply has become indispensable during the maintenance task of active electric power lines as a result of today's highly information-oriented society and increasing demand of electric utilities. The maintenance task has the risk of electric shock and the danger of falling from high place. Therefore it is necessary to realize an autonomous robot system. In order to realize these tasks autonomously, the there dimensional position of target object such as electric line and the stand of insulator must be recognized accurately and rapidly. The insertion task of an electric line into a sleeve is selected as the typical task of the maintenance of active electric power distribution lines in this paper. A modified hough transform is applied to the recognition of the center of electric line and optimal target position calculation method is newly derived in order to recognize the center 3 dimensional position of the electric line. By the proposed method, it is proved that the center position of the electric line can be recognized without respect to the noise of image and the shape of electric lines and the insertion task of an electric tine is realized.

• Computers and Concrete
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• v.14 no.3
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• pp.263-277
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• 2014

This study investigated four electric field configurations of two-dimensional accelerate lithium migration technique (ALMT), including line-to-line, plane-to-line, contour-to-line and plane-to-plane, and analyzed the ion migration behavior and efficiency. It was found that the free ion distribution diagram and voltage distribution diagram were similar, and ions migrated in the power line direction. The electrode modules were used for the mortar specimen with w/c ratio of 0.5. The effectively processed areas accounted for 14.1%, 39.0%, 49.4% and 51.4% of total area respectively on Day 28. Larger electrode area was more advantageous to ion migration. In addition, it was proved that the two-dimensional electric field could be divided into different equifield line active regions, and regarded as affected by one-dimensional electric field, and the ion migration results in various equifield line active regions were predicted by using the duration analysis method based on the theoretical model of ion migration obtained from one-dimensional test.

• Journal of Mechanical Science and Technology
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• v.16 no.12
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• pp.1633-1642
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• 2002

Uninterrupted power supply has become indispensable during the maintenance task of active electric power lines as a result of today's highly information-oriented society and increasing demand of electric utilities. The maintenance task has the risk of electric shock and the danger of falling from high place. Therefore it is necessary to realize an autonomous robot system using electro-hydraulic manipulator because hydraulic manipulators have the advantage of electric insulation. Meanwhile it is relatively difficult to realize autonomous assembly tasks particularly in the case of manipulating flexible objects such as electric lines. In this report, a discrete event control system is introduced for automatic assembly task of electric lines into sleeves as one of the typical task of active electric power lines. In the implementation of a discrete event control system, LVQNN (linear vector quantization neural network) is applied to the insertion task of electric lines to sleeves. In order to apply these proposed control system to the unknown environment, virtual learning data for LVQNN is generated by fuzzy inference. By the experimental results of two types of electric lines and sleeves, these proposed discrete event control and neural network learning algorithm are confirmed very effective to the insertion tasks of electric lines to sleeves as a typical task of active electric power maintenance tasks.

• Proceedings of the KIEE Conference
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• 2005.10c
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• pp.155-157
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• 2005

This paper analyzed the adoption possibility of a low cost single phase active power filter as the neutral current reduction device in three-phase four-wire power system with the balanced or/and unbalnaced nonlinear load conditions. Proposed system can make neutral line current to within rated vale without the phase current THD change of the installed phase line.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.57 no.4
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• pp.424-430
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• 2008

A new active vibration measurement system in electric power transmission line is presented, using in the nondestructive test. With a permanent magnet and a couple of coils, the system exerts impact force to a test object and in turn picks up the vibration of the object. The natural frequency with the amplitude obtained from the system are used as a basis for the detection of defects in the object. The system is controlled by an electronic device designed to facilitate the fully automated testing process with consistent repeatability and reliability which are essential to the nondestructive test. The system is expected to be applied to the wide area of defect detection including the classification of mechanical parts in production and inspection processes.

• Proceedings of the KIPE Conference
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• 2003.07b
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• pp.729-733
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• 2003

This paper proposed a novel current control strategy on active power filters using p-q-r instantaneous power theory which can compensate the line current harmonics and the neutral line current in unbalanced and/or distorted source conditions in three-phase four-wire systems. The proposed current control method is based on a sinusoidal PWM for fully-digital implementation which was compared with a hysteresis PWM. Simulation results showed good performance of the proposed current control strategy on shunt type APFs.

• The Transactions of the Korean Institute of Power Electronics
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• v.3 no.3
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• pp.184-190
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• 1998

Most buildings and factories are supplied with electric power by three-phase four-wire low voltage electric distribution system. This method pollutes the neutral line and utility sources with harmonic currents. Today, development of power conversion technology and the popularization of computer cause the neutral current to become serious. In this paper, a novel three-phase four-wire active filter is proposed to solve these harmonic problems has two purposes. The first purpose of the proposed active filiter is that the phase current has a sinusoidal waveform shape under the nonlinear load. The second purpose of the proposed active filiter is that the current on the neutral line become zero under the unbalanced power source and under the varring load conditions. The ability of the shunt active filiter has been proved to be excellent through simulations under the varring load conditions.

• Proceedings of the KIPE Conference
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• 2019.07a
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• pp.326-327
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• 2019

본 논문은 분산전원의 증가로 복잡해진 배전 계통의 효율적인 운영을 위해 배전선로의 재구성을 연구하며, 각 배전선로를 연계하기 위해 능동위상제어기를 이용하여 배전선로간의 연계방안을 제안한다. 능동위상제어기의 개념을 설명하고, 배전 선로의 연결을 위해 연계 지점의 전압 크기와 위상을 동기화하는 방법을 제안한다. 제안한 방법은 시뮬레이션을 통해 검증한다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07b
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• pp.1121-1124
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• 2004

Aging test to estimate life property of polymer insulator is executed through several international standard such as IEC 61109 and CEA tracking wheel test, but is not getting clear conclusion yet. There are two methods in the diagnosis method of polymer insulator such as off-line and on-line. The diagnosis methods in off-line are external condition analysis by the eye, contaminant analysis on surface, surface analysis, pollution withstand voltage test, power frequency flashover voltage test, lightning impulse flashover test, tensile fracture load test and flexural load test. The diagnosis methods in off-line most are the method for virgin and last aged sample. However, the diagnosis method in on-line is method that can be evaluate sample state as progressing continuously aging test in beginning, The diagnosis method in on-line is arranged as following: leakage current measurement, electric field, surface state investigation, thermal image, emitting light measurement and then so. In this paper, the tracking performance of polymer insulator with salt solution which is added surface active agent. The diagnosis of insulator sample has been analyzed by leakage current and visual examination.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.804-808
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• 2007

when electric traction system used DC 1500V runs on decline of rail road track and slows down, Dc voltage goes beyond regular voltage. In this case extra power is forcibly wasted by resister because rectifier of substation and electric train including power converter and so on are out of order. This paper described a DC electric railway system, which can generate the excessive DC power form DC bus line to AC source in substation for traction system. The proposed regeneration inverter system for DC traction can be used as both an inverter and an active power filter(APF). As a regeneration inverter mode, it can recycle regenerative energy caused by decelerating tractions and as an active power filter mode, it can compensate for harmonic distortion produced by the rectifier substation. In addition, electric traction system products harmonic current and voltage distortion and reactive power because power converter is used so regeneration inverter normally runs such as active power filter(APF) for improving power quality. From the viewpoint of both power capacity and switching losses, the system is designed on the basis of three phase PWM inverters and composed of parallel inverters, output transformers, and an LCL filter.