• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2007.05a
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• pp.440-445
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• 2007

This paper deals with assessment of risk component for electrical safety and investigation on the spot of computer room in elementary middle high school. The investigation was carried out side by side for floor, outlet, panel board, earth leakage circuit breaker at computer room In order to assess electrical safety at computer room, grounding simulator and power quality monitor have been used. Potential rise has been measured and analyzed for ground rod and grounding grid by using the simulator. Phase and neutral-line current have been monitored in real time. As a consequence, it is desirable for us to install conductive tile at floor of computer room Grounding grid had better than ground rod for electrical safety. Neutral-line current was produced by unbalanced phase current.

• Journal of Electrical Engineering and Technology
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• v.8 no.3
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• pp.588-594
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• 2013

Under the condition of Baader aging, the chemical composition variation and the influence of transformer oil aging on electrical properties such as dielectric loss factor and physic-chemical properties such as interfacial tension were studied in the aging precess. Moreover, the correlation between hydrogenated transformer oil electrical and physic-chemical properties and its chemical composition variation were also investigated. The results show that these parameters of physic-chemical and electrical properties of hydrogenated transformer oil relate to each other and have closed correlation with chemical composition.

• Journal of Electrical Engineering and Technology
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• v.5 no.4
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• pp.614-622
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• 2010

This paper presents a control method, which reduces the pulsating torque and DC voltage problems of a doubly fed induction generator (DFIG)-based wind turbine system. To reduce the torque and power ripple, a current control scheme consisting of a proportional integral (PI) controller is presented in a positive synchronously rotating reference frame, which is capable of providing precise current control for a rotor-side converter with separated positive and negative components. The power theory can reduce the oscillation of the DC-link voltage in the grid-side converter. In this paper, the generator model is examined, and simulation results are obtained with a 3 kW DFIG-based wind turbine system to verify the proposed control strategy.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.2
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• pp.4-9
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• 2009

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.12
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• pp.2221-2224
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• 2011

During an emergency due to a shortage of power, a load aggregator (LA) can use the demand response operation system to deploy demand response resources (DRRs) through various demand response (DR) programs. This paper introduces the demand response operation system for a load aggregator to manage various demand response resources in a smart grid environment.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2002.11a
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• pp.303-306
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• 2002

This paper presents a novel method for measuring the ground impedance in grounding systems. A square wave current was injected to the main grounding grid through auxiliary electrode, and the test current and ground potential rise(GPR) were measured using the band-pass filter. Ground impedance was calculated from the sinusoidal waveforms of the test current and GPR in frequency range of 20~2100Hz. Also the resistance and reactance component of ground impedance were analyzed.

• Proceedings of the KIPE Conference
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• 2019.07a
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• pp.467-468
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• 2019

This paper proposes an improved bus voltage regulation scheme in filter-based reference current generation of power management for DC home grid with photovoltaics (PV), battery, and ultracapacitor (ultracap) by using feedforward terms instead of the filter output to produce the ultracap reference current. Simulation results have proved the effectiveness of the proposed scheme.

• International Journal of Internet, Broadcasting and Communication
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• v.12 no.2
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• pp.1-7
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• 2020

The secure access the lighting, Heating, ventilation, and air conditioning (HVAC), fire safety, and security control boxes of building facilities is the primary objective of future smart buildings. This paper proposes an authorized user access to the electrical, lighting, fire safety, and security control boxes in the smart building, by using color grid coded optical camera communication (OCC) with face recognition Technologies. The existing CCTV subsystem can be used as the face recognition security subsystem for the proposed approach. At the same time a smart device attached camera can used as an OCC receiver of color grid code for user access authentication data sent by the control boxes to proceed authorization. This proposed approach allows increasing an authorization control reliability and highly secured authentication on accessing building facility infrastructure. The result of color grid code sequence received by the unauthorized person and his face identification allows getting good results in security and gaining effectiveness of accessing building facility infrastructure. The proposed concept uses the encoded user access authentication information through control box monitor and the smart device application which detect and decode the color grid coded informations combinations and then send user through the smart building network to building management system for authentication verification in combination with the facial features that gives a high protection level. The proposed concept is implemented on testbed model and experiment results verified for the secured user authentication in real-time.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.8
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• pp.1605-1614
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• 2009

The technique of simultaneous localization and mapping is the most important research topic in mobile robotics. In the process of building a map in its available memory, the robot memorizes environmental information on the plane of grid or topology. Several approaches about this technique have been presented so far, but most of them use mapping technique as either grid-based map or topology-based map. In this paper we propose a frame of solving the SLAM problem of linking map covering, map building, localizing, path finding and obstacle avoiding in an automatic way. Some algorithms integrating grid and topology map are considered and this make the SLAM performance faster and more stable. The proposed scheme uses an occupancy grid map in representing the environment and then formulate topological information in path finding by A${\ast}$ algorithm. The mapping process is shown and the shortest path is decided on grid based map. Then topological information such as direction, distance is calculated on simulator program then transmitted to robot hardware devices. The localization process and the dynamic obstacle avoidance can be accomplished by topological information on grid map. While mapping and moving, pose of the robot is adjusted for correct localization by implementing additional pixel based image layer and tracking some features. A laser range finer and electronic compass systems are implemented on the mobile robot and DC geared motor wheels are individually controlled by the adaptive PD control method. Simulations and experimental results show its performance and efficiency of the proposed scheme are increased.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.5
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• pp.129-135
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• 2010

It is well known that distributed generation(DG) system using renewable energy is an alternative to solve the problems which result from the exhaustion of fossil fuel and the environmental pollution. A PWM inverter is required for a power flow control in the DG systems. This paper proposes a SRF power flow control method considering grid impedance in grid-connected single-phase inverter systems. The proposed SRF power flow control method can provide a voltage-reference for the single-phase inverter even without any grid impedance estimation so that the single-phase inverter system could operate in stand-alone mode and grid-connected mode based on the known nominal value of grid impedance. Also independent controls of active and reactive power are achieved by the proposed control method. The effectiveness and the validity of the proposed control method are demonstrated through simulations. The simulation results show that the proposed control method can control properly power flow in grid-connected single-phase inverter systems.