• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.1
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• pp.720-723
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• 2005

There has been significant progress in the development of timed process algebra for the specification and analysis of real-time systems in recent years. ACSR is a timed process algebra, which supports synchronous timed actions and asynchronous instantaneous events. Timed actions model the usage of shared resources and the passage of time, whereas events allow synchronization between processes. To be able to specify real-time systems more effectively, this paper suggests the notion of probabilities. This paper also illustrates extended PACSR with a typical resource allocation system and its deadlock specification and analysis.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.2
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• pp.927-930
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• 2005

ACSR is a timed process algebra for the specification and analysis of real-time systems, which supports synchronous timed actions and asynchronous instantaneous events. PACSR is an extended ACSR with the notion of probabilities in selection operation. Using PACSR, this paper represents a system fault occurrence and recovery from the fault in the general resource alteration system. The result shows that system fault occurrence can be analyzed from the fault occurrence probability and the recovery probability.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.14 no.6
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• pp.43-50
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• 2000

Design and experiments of a nondestructive testing system with a solenoid eddy current sensor to inspect deterioration of ASCR-OC (ACSR Outdoor Cross-linked Polyethylene Insulated Wires) usually used in HV overhead distribution lines in domestic areas in presented in this paper. Through corrosion mechanisms and deterioration results for ACSR-OC conductors are examined, it is shown that corrosion may lead to the reduction of the effective cross section area of conductors is proposed. The measurement system consisting of a constant current source with a RF frequency, a signal processing unit and a motor driver/ controller is designed and implemented. This instrument has such capabilities as detecting the sensor output and estimating diameter change of the testing conductors, continuously. As a result, it was verified that such corrosion detector system with an eddy current sensor can be shown good effectiveness for estimating the serious faults due to deterioration in overhead distribution lines and giving an early warming before severe aged conductor may lead to fail.

• Journal of Electrical Engineering and Technology
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• v.10 no.5
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• pp.2070-2076
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• 2015

Nano composite materials were multi-constituent combinations of nano dimensional phases with distinct differences in structure, chemistry and properties. Nano particles were less likely to create large stress concentrations and thereby can avoid the compromise of the material ductility while improve other mechanical properties. Corona discharge was an electrical discharge. The ionization of a fluid surrounding a conductor was electrically energized. This discharge would occur when the strength of the electric field around the conductor was high enough to form a conductive region, but not high enough to cause electrical breakdown or arcing to nearby objects. This paper shows all the studies done on the preparation of nano fillers. Special attention has given to the ACSR transmission line conductor, TiO₂ nano fillers and also to the evaluation of corona resistance on dielectric materials discussed in detail. The measurement of the dielectric properties of the nano fillers and the parameters influencing them were also discussed in the paper. Corona discharge test reveals that in 0%N ACSR sample corona loss was directly proportional to the applied line voltage. No significant change in corona loss between 0%N and 1%N. When TiO₂ nano filler concentration was increased up to 10%N fine decrement in corona loss was found when compared to base ACSR conductor, corona loss was decreased by 40.67% in 10%N ACSR sample. It was also found from the surface conditions test that inorganic TiO₂ nano filler increases the key parameters like tensile strength and erosion depth.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.17 no.6
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• pp.160-168
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• 2003

In Korea, a large portion of aerial power-transmission cables is installed in the mountains. In the case of a fire in the mountains, steel wires coated with zinc and aluminum wires of those power cables exposed to the fire or near around will be deteriorated by the blaze and the high temperature. Deterioration proceeds by interactions of a variety of factors like quality, manufacturing process, the condition of installation and exposure environment of a wire, and so on. Generally, the characteristic of a conductor affect by a forest fire can not be analyzed without the effect through simulating a forest fire. However, there are little research accomplishments of that kind of simulation about it, and there's been no analysis of a sample exposed to an actual forest fire. This thesis shows the experimental results that apply to a new wire by an artificial flame-maker because it's difficult to directly analyze the characteristic of deterioration by a forest fire. Those results include the intensity of extension and wrench for a conductor. In addition, there's been an experiment and analysis about the mechanical characteristics of the wire of ACSR 480[$\textrm{mm}^2$] which was removed from Pohang area by a forest fire. Then, the database will be made to predict the state of deteriorated wires by a forest fire using those two data, and data necessary to diagnose the life state of an ACSR wire affected by a forest fire will be given.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.407_408
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• 2009

Generally, the deterioration characteristics of a conductor affected by a forest fire can be analyzed through simulation of a forest fire and results of the simulation. However, there are little accomplishments of that kind of simulation applied to the power transmission, and there aren't actual analysis for a sample exposed in a forest fire. This paper deals with the experimental results that apply to a new wire by an artificial flame equipment because it's difficult to directly analyze the characteristic by a forest fire. Also, after an artificial flame is applied to a normal ACSR for various experimental conditions, changes of mechanical and material characteristics of the ACSR were analyzed by the surface inspection and load-tests of tensile of the ACSR. Then, the database will be made to made to predict the state of deteriorated wires by a forest fire using those two data, and data necessary to diagnose the life state of an ACSR wire affected by a forest fire will be given.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.13 no.1
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• pp.77-85
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• 1999

This paper deals with an experirrental study of a nondestructive testing system using a solenoid eddy currnet sensor to inspect deteriorations in overhead distribution lines, such as broken wires, severe local corrosion or zinc loss. Corrosion rrechanisrn for ACSR and ACSR-OC is discussed and characteristics for a solenoid sensor to insprt the georretrical pararreters of the coil and testing materials impOOance are briefly analyzed. A measurement system having a constant current source, a signal processing unit and a motor driver is impIemented. This instrument has such capabilities as detecting the sensor output and estimating dinHlsions of the testing conductors, continuously. As a result, it was shown that the eddy current sensor with an encircling coil could effectively estimate the diatreter change due to deteriorations in overhead distribution lines. lines.

• Journal of KIISE:Computing Practices and Letters
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• v.6 no.6
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• pp.608-619
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• 2000

In this paper, we give a formal semantics for Statechart via a translation into Algebra of Communicating Shared Hesources(ACSR). Statechart is a very rich graphical specification language, which is suitable to specify complicated reactive systems. However, the incorporation of graph into specification and rich syntax makes Statechart semantics very complicated and ambiguous. Thus, it is very difficult to verify the correctness of Statechart specifications. Also, we propose the formal verification method for Statechart specifications by showing equivalence relation between two Statechart specifications. This makes it possible to combine the advantages of a graphical language with the rigor of process algebra.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.282-282
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• 2009

Forest Fire can cause a serious damage to overhead conductors. Therefore, the detailed investigation for the changes of mechanical and electrical properties of damaged conductors should be carried out to understand the effect of forest fires on conductors. This is very important to maintain transmission line safely. Specimenes for this study were Al conductores of ACSR $410mm^2$, ACSR 480 R and ACSR $240mm^2$. This paper describes the changes of mechanical and electrical properties of same flame exposed Al conductor. The detailed will be given in the text.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.307_308
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• 2009

본 연구에서는 아연도강연선을 인류주에 보통지선으로 시설할 때 전선의 불평균장력을 지지할 수 있는 최대허용불평균장력을 계산 후 현재의 가공배전선 중 가장 많이 사용하는 ACSR/AW-TR/OC 전 규격에 대하여 기준이도로 시설시 최악조건의 상정최대장력과 비교함으로써 기준이도의 재설정 필요성 여부를 검토하고자 하였다. 연구 결과 ACSR/AW- TR/OC $160mm^2$ 및 $240mm^2$은 장경간 개소의 고온계 강화 지역 상정최대장력보다 단경간 개소의 저온계 상정최대장력이 큼을 발견하였고, 지선을 아연도강연선 7/3.5mm이하로 시설 가능하도록 ACSR/AW- TR/OC $160mm^2$ 및 $240mm^2$의 기존이도를 재설정하는 연구를 진행할 필요성이 있음을 확인하였다.