• Congress of the korean instutite of fire investigation
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• 2011.04a
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• pp.77-97
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• 2011

In this paper, we studied risk assessments of electrical fire and shock of LED lightings for outdoor. We examined national regulations about the LED lighting for outdoor and analyzed the appearances and compositions of LED lightings. And, We experimented about water proof, line to line fault, line to line breakdowm, overvoltage, line to line leakage in overhead line or water of LED lighting. From experimental results, we know that there are risks of electrical fire and shock by abnormal conditions at the LED lighting. Therefore, the uses of protective devices and insulated type of converter are required for the electrical safety. We expect that the results of this study would be helpful for the improvement of regulations and standards for electrical safety and for the investigations of electrical accidents of LED lightings.

• KIEAE Journal
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• v.10 no.1
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• pp.57-64
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• 2010

Electric energy is indispensible of the development of the industrial and living sector. Among the energy sectors, the building area shares 20% of the produced electric power in Korea. As we plan to supply the apartment, we need to forecast the required amount of the electric energy and supply the infrastructure to apartment for the lighting, cooling. Nonetheless, it is not easy to forecast the required amount of the electric energy, considering the management aspect, building physical aspect and social-geographic aspect. In this paper, it studied the estimation model of the electric energy, reflecting the affecting variables such as total area, number of household, geography and so on. The estimation model is proposed in 3-types which explained in central heating, individual heating and district heating, and each type have two estimation model, reflecting the affecting variable and corelation between variables to eliminate the muticolinearity. The unit of electric energy consumption per area and year is similar in three heating type and the results are as follows; the central heating is $34.446kWh/yr{\cdot}m^2$, individual type is $35.756446kWh/yr{\cdot}m^2$ and district heating is $34.285446kWh/yr{\cdot}m^2$.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.5
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• pp.65-70
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• 2015

Lightning is one of hazards affecting the rapid-transit railway system. There are two effects, which are direct lightning surge to electric car line and induced lightning surge. Protection methods for the direct lightning surge are studied with various occasions, however, study of induced lightning surge is insufficient in spite of a large or small effects. In this paper, it is analysed the way that serge voltage is induced to electric car line by lightning strikes. By modeling the propagation process and the coupling phenomenon of electromagnetic wave produced by lightning strikes, it is achieved to make integrative circuit model combined with existing electric car model. The study is conducted into three different waveform of electromagnetic wave produced by lightning; rectangular wave, double exponential distribution wave, triangle wave. It is also simulated that the inducing serge is coupled to electric car line in an arbitrary location. The simulation results in that, when rapidly changing rectangular wave is supplied, maximum power is induced to electric car line.

• Journal of Climate Change Research
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• v.1 no.3
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• pp.205-210
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• 2010

LED light has various advantages such as an energy saving effect of over 80% compared to existing lighting and environmentally friendly characteristics; however, there has been no affordable market for LED lighting because of its expensive price. This study discussed the validity of the expansion of distribution of LED lighting through an assessment of economic efficiency concerning LED lightening in order to analyze its efficiency in terms of energy savings and maintenance and repair, which will be generated as a result of the change from existing incandescent bulbs to LED lighting in the public sector. As to the target of analysis, the paper reviewed the validity of change to LED lighting as a result of the elimination of existing incandescent bulbs, by referring to 'the current incandescent bulb use and elimination performance' published by the Ministry of Knowledge Economy based on the "Elimination management system" executed by Korea Energy Management Corporation. The paper considered expenses for change, annual power savings amount and electric charges savings amount, repair and maintenance cost, $CO_2$ reduction volume, and the profit from the sale of CER (certified emission reduction). As a result of analyzing economic efficiency, when the discount rate during the change of existing incandescent bulb lighting to LED lighting is 3.26%, the profit was 8,648,400,000 won. Accordingly, NPV was analyzed to have a 'positive (+)' value, which means that this change is profitable.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.2
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• pp.306-312
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• 2014

The ZigBee communication method, which is the most frequently applied to the LED lighting control system, has drawbacks of low-speed and low-capacity, and the communication failure possibility due to environmental influences is on the rise. Therefore, it is important to secure the communication reliability by applying an integrated interface with a wire-wireless dual-network. This paper developed a communication module, which has a platform converging and combining the ZigBee of USN environments with the PLC of power line communication environments, to implement a dualized communication interface system supporting the wire-wireless integrated protocol, and implemented a wire-wireless networking device and a control system software technology. As a result, it was automatically switched into the PLC communication within 4.4 seconds on average when there was an access failure in the ZigBee communication network, so a reliable communication network was built.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.8
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• pp.1101-1107
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• 2013

A light emitting diodes(LED) lighting has been increasingly used due to its low power consumption, long life time, high efficiency, and environment friendly characteristics. Also various power converters has been applied to drive these LED lighting. Among many power converters, a LLC resonant converter could be applied for LED lighting because of its high efficiency and high power density. Furthermore, the function of power factor correction(PFC) might be added. In this paper, 1-stage asymmetrical LLC resonant converter is proposed. The proposed converter performs both input-current harmonics reduction and PFC using the discontinuous conduction mode(DCM). The proposed 1-stage LLC resonant converter approach has the lower voltage stress across switching devices and achieve the zero voltage switching(ZVS) in switching devices. To verify the performance of the proposed converter, simulation and experimental results from a 300[W] prototype are provided.

• Journal of Korean Tunnelling and Underground Space Association
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• v.13 no.5
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• pp.371-383
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• 2011

It is important to secure illumination for the driver's safety because the tunnel is a space for changing brightness quickly, and lighting fixtures of the tunnel have consumed a lot of electric lighting energy for operating in both the daytime and at night. This study aims to evaluate daylighting performance of Mirror Reflector System for luminous environment improvement of tunnel space by using RADIANCE simulation program. The results of simulation show that illuminance of bar type is higher than illuminance of pole type at 20 m from the tunnel entrance.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.12 no.2
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• pp.13-18
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• 2016

Energy saving has been main concern, thus government supporting policies which are based on Fundamentals of Low-carbon Green Growth Act', 'Green Building Support Act, have been prepared in Korea. The objective of this study is to estimate energy conservation effectiveness and economic advantage assuming that lighting equipments and heat source equipments would be retrofitted. Office building, which has total floor area of $30,000m^2$, was a subject of this study. From the estimations, electric rate will be decreased by 62,886,000 won per year due to lighting equipments retrofit, and gas rate will be decreased 11,141,000 won or 17,332,000 won per year due to heat source equipments retrofit (in case of COP 1.2 or 1.5). Payback period of each case that are calculated by energy saving cost and retrofit cost are estimated 27.9 year, 38.6 year and 29.2 year, thus economic supporting policies is necessary for effective energy saving in buildings. Meanwhile payback period of heat source equipment for new building is estimated 6.1 year and 8.3 year.

• Journal of information and communication convergence engineering
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• v.11 no.4
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• pp.247-252
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• 2013

An intelligent light emitting diode (LED) dimming system is designed and implemented for energy-saving lighting systems. An LED light bulb is powered by an LED driver controlled by a microcontroller using pulse width modulation (PWM) signals. By changing the duty cycle of the PWM signals, the LED driver generates a driving current of up to 1,000 mA. The current consumption by the LED light bulb exhibits a very linear characteristic that indicates that the level of LED dimming can be finely tuned. Multiple sensors-lighting intensity and ultrasonic range sensors-are combined with the LED dimming system to realize an automatically controllable LED lighting system. The light intensity sensor is capable of sensing ambient light. The ultrasonic range sensor can detect objects from 0.15 to 5.6 m at a resolution of 0.0254 m. The collected information by the light intensity and ultrasonic range sensors is processed by the microcontroller that in turn automatically controls the brightness of the LED light bulb. The algorithm of the software for the LED dimming system is also described.

• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.5
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• pp.1029-1036
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• 2018

This paper is a study on the development of optimal control system for lighting and air conditioning equipment to save the energy in campus environment. In the case of controling system developed through this research, lighting and air conditioner are controlled by both information on the number of people entering and leaving the room through the motion sensor and image processing, and the information on temperature and humidity. In addition, energy saving is enabled by the results that are controlled through data integration monitoring and command execution functions according to the control signals.