• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.26 no.10
• /
• pp.81-88
• /
• 2012

Surge protective devices(SPDs) are widely used as a most effective means protecting the electrical and electronic equipment against overvoltages such as lightning and switching surges. When installing SPDs, it is essential that the voltage protection level provided by SPDs should be lower than the withstand voltage of the equipment being protected. But even the proper selection of SPDs are achieved, the voltage at the equipment terminal may be higher than the residual voltage of SPD due to the reflection and oscillation phenomena. This paper was focused on the investigations of the conditions for which the equipment is protected by an SPD taking into account the influences of the protective distance and type of load. The protective effects of SPD with voltage-limiting component were analyzed as functions of types of load and protective distance between the SPD and load. As a result, in the cases of long protective distances, capacitive loads and loads with high resistance, the voltage at the load terminal was significantly higher than the residual voltage of SPD. It was found that the proper installation of SPDs should be carried out by taking into account the protective distance and type of load to achieve reliable protection of electronic equipments against surges.

• KIEAE Journal
• /
• v.16 no.6
• /
• pp.39-50
• /
• 2016

Purpose: The purpose of this study is to be performed with studio-type housings among urban life-type housings to investigate the physical characteristic and crime-related factors of studios from the viewpoint of the basic principles of crime prevention through environmental design (CPTED). Method: Eight CPTED guidelines available in Korea were reviewed to select 20 planing factors for actual condition investigation. Five single households in studio-type housings in Gwanak-gu, Seoul, were chosen according to the subject screening criteria to perform the actual condition investigation. Results: First, a lighting plan around a building for natural surveillance should consider the building location, relation with the front road, and surrounding facilities. In a building of a piloti structure, the parking lot and the building gate should be arranged in a manner that enables natural surveillance. Second, the shape of the corridors in studio-type housings should be considered to plan the installation of a lighting at the door of each household, the installation of a viewer window at the door of each household, and the arrangement of the elevator. Third, to support access control, an access control system having the function of video and voice communication is recommended to be installed at the building gate. Criteria for the type of security windows and the floors on which security windows should be installed, and the regulations about the CCTV installation inside and outside the building should be prepared. Fourth, to enhance territoriality in parking lots, ground patterns, parking lot gate, and signs may be installed. Fifth, in view of effective utilization and maintenance, lighting facilities should be installed to increase the usability of ground parking lots, and relevant installation criteria should be prepared regarding the type, number, and brightness of the lightings.

• Journal of Biosystems Engineering
• /
• v.16 no.1
• /
• pp.83-89
• /
• 1991

One of the most serious problems in Korean sericulture farms is to improve the adiabatic conditions for the simple silkworm rearing houses which has been widely adapted since early 1980'. Thus, this study is aimed to solve the problems by selecting the thermal screen material and by finding the method of its instalation. For the study, 4 kinds of materials which are (1) TE005,(2) NW60, (3) NW300 and (4) AL110 are selected and 4 different types of methods which are surrounding boundary of rearing bed(type A), surrounding inside of wall and ceiling (type B), installing on inside of wal ony (type C) and installing on ceiling Inly (type D) are installed. Decision criteria of the best combination of screen material and installation methods is made by calculating the heating load coefficients and by testing the application at the simple silkworm rearing houses. The obtained results are summarized as follows ; 1. The effect of thermal screen on reducing the thermal energy is remarkable. It saves energy more 50% than unscreened simple silkworm rearing houses. 2. From a stand point of a good screed material on thermal energy reduction, the NW300, AL110 and PE005 are recommanded materials. However, NW60 and PE005 are regarded as desirable materials from the practical point view. 3. Also, the effect on thermal energy reduction is largely affected by the method of thermal screen installation. The surrounding boundary of the silkworm rearing bed(type A) is the most desirable method to reduce the energy, which saves 56.6% of it. 4. In the practical application, NW60 and type A is considered to be the best combination of material and installation method. By this combination, the level of maximum heating load can be reduced at the rate of 43% for spring season and 40% for autumn season. 5. Another heating method, comparted heating, can be recommended to save the energy.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.36 no.6
• /
• pp.1075-1082
• /
• 2016

In order to calculate the optimum installation interval between a speed hump and hump type crosswalk that are installed continuously in succession, this study examined the speed of a vehicle that passes different intervals between speed humps and hump type crosswalks from the approach section of a roundabout having a maximum speed limit of 30km/h; analyzed the effects of speed humps and hump type crosswalks installed continuously in succession on vehicle driving speed; and simulated the optimum installation height of hump type crosswalk. As a result, the following conclusion was drawn. First, it was found that the optimum interval between a speed hump and hump type crosswalk, which are the representative traffic calming techniques for reducing vehicle speed, to control vehicle speed under 30km/h is 30m. Second, as a result of comparing the deceleration of a vehicle that pass hump type crosswalks, it was found that if the installation interval is 65 m and above, a speed hump and hump type crosswalk had no effect. Therefore, it is desirable that the maximum installation interval between a speed hump and hump type crosswalk for controlling vehicle speed within a fixed road section should not exceed 65m. Third, the analysis showed that the optimum installation height of hump type crosswalk is 6-8cm in case vehicle speed at the approach section is 20km/h or lower, 8-10cm in case of 30km/h, and 10cm in case of 30km/h or higher, respectively. Fourth, even at a road section on which a speed hump and hump type crosswalk are installed, speed reduction effects may sometimes be insignificant due to a driver's studying effect, traffic conditions and so on. Thus, it is judged that speed reduction effects will be greater if several traffic calming techniques such as speed hump, chicane, and choker are applied at the same time. Therefore, in case of applying traffic calming techniques for the purpose of reducing vehicle speed in order to promote pedestrian safety, the composite application of several techniques should be considered.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.19 no.6
• /
• pp.49-60
• /
• 2020

The number of traffic control equipment installed to prevent traffic accidents increases every year due to continuous installation by the National Police Agency and local governments. However, it is installed based on qualitative judgment rather than engineering analysis results. The purpose of this study was to present additional installations in the future by presenting the installation criteria considering the severity of accidents for each road type and calculating the appropriate number of installations. ARI indicators that can indicate the severity of traffic accidents were developed, and road types were classified through analysis of variance and cluster analysis, and accident information by road type was analyzed to derive ARI of clusters with high traffic accident severity. The ARI values required to determine the installation of equipment for each road type were presented, and 5,244 additional installation points were analyzed.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.7 no.4
• /
• pp.26-33
• /
• 1993

The acoustic emission automatic detection system is developed to observe tree deterioration phenomena. Applying an alternating voltage of 15(kVnns) toXLPE tree specimens, many pulses of small amplitude are detected when the bush type tree developes branch type and a few pulses of high amplitude prcxluced as branch type propagated to bush type tree. Therefore, it is known that pulses having small amplitude operates as a destructive factor. It is observed that the skewness of the amplitude and the number of average pulses as distribution tendency of three dimension are characteristic quantity of AE pulses. As the trajectory of skewness is farther from the origin on the S-plane, it is more likely to breakdown.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.25 no.5
• /
• pp.39-44
• /
• 2011

Automatic fire alarm system is set up to automatically detect fire on buildings. Because of economic reasons, P-type receiver and a conventional type fire detector is normally used for automatic fire alarm system in Korea. Because early detection of fire is regarded as important, the need of finding technique of fire location increases. This paper is studied a method to improve a reliability and add a function of fire location detection on a conventional type fire detector and P-type receiver. Fire location is detected by a method that controller attached on the receiver and the detector is read with a time lag. A reliability of fire detection alarm system is improved with a method that false fire alarm is able to decrease using two different principle detector together. This paper is studied for basic data of improvement of low-cost addressable automatic fire alarm system.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.25 no.1
• /
• pp.113-117
• /
• 2011

As one of the countermeasures to solve the increase of the fault current in a power system, the superconducting fault current limiter (SFCL) has been noticed together with the development of a various types of SFCL, which has accelerated the researches to apply a SFCL into a power system. Among the developed SFCLs, the transformer type SFCL is expected to be available for adjusting the voltage and the current ratings of the SFCL. In this paper, the fault current limiting and the bus line‘s voltage sag suppressing effect by the transformer type SFCL were investigated and the case without the transformer type SFCL was compared as well. Through the analysis on the results of the short-circuit tests, the fault current limiting and the bus-line voltage suppressing characteristics of the transformer type SFCL could be confirmed to be effectively performed.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.28 no.8
• /
• pp.62-68
• /
• 2014

The series connection type superconducting fault current limiter (SFCL) with added third winding, which was magnetically coupled in one iron core, was proposed. The proposed SFCL was expected to be more improved by just adding third winding into the conventional series connection type SFCL with two coils. To analyze the contribution of the third winding for the current limiting and the recovery characteristics of the SFCL, the short-circuit tests for the series connection type SFCL with the added third winding were performed together with the analysis on its electrical equivalent circuit. From the comparative analysis on the amplitude of the limited fault current and the power burden of the high-TC superconducting (HTSC) element comprising this SFCL, the improved current limiting and recovery characteristics of the series connection type SFCL using the third winding could be confirmed.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.25 no.4
• /
• pp.71-78
• /
• 2011

This paper contains the selection of operation parameters for protection and control of steam turbine in a Korea Standard Type Nuclear Power Plant. The safety of nuclear reactor must be ensured which generates nuclear energy and produces steam. Also, the safety of turbine, which consume the nuclear energy as a core machine, must be ensured. For the purpose of this, we describe how the operating parameters were selected, reviewed, implemented into the operator console and finally put into actual operation of the system.