• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.1
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• pp.59-64
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• 2016

This paper aims at the prototype-making of the intelligent switchgear with arc fault diagnosis function required to prevent the electrical fire. The main control unit of the intelligent switchgear consists of a single-phase power management device and a arc fault diagnosis device. The prototype of the single-phase power management device and the prototype of the arc fault diagnosis device in this paper. In the device, the cooperation function with the arc fault diagnosis device is developed to transmit the cause of the electrical fire to the remote server system.

• The Transactions of the Korean Institute of Power Electronics
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• v.10 no.1
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• pp.61-69
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• 2005

The topology of NPC inverter coupled with the large number of devices used increases the probability of device failure. It's necessary to develop an optimal remedial strategy which can be used to continue the application when fault occurs. The fault tolerance is obtained by the use of the proposed method. The proposed method utilizes that the one phase load with the failed power device could be connected to the center-tap of the DC-link capacitor in order to dc-link voltage with balance and the sinusoidal phase current with constant amplitude under the single power device fault condition. The strategy described in this paper is expected to provide an economic alternative to more expensive redundancy techniques.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2003.02a
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• pp.43-46
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• 2003

The dc reactor type high-Tc superconducting fault current limiter(SFCL) is composed of three parts, a power converter, a magnetic core reactor(MCR) and a dc reactor. This study concerned with the power converter of the DC reactor type high-Tc SFCL. The rectifying devices which power converter of 6.6kV/200A SFCL consists of have to endure high voltage. We propose the dual mode power converter to reduce the voltage which each rectifying device endures. In the single phase the experiment and simulation of dual mode power converter and the simulation of power converter with one bridge rectifier are performed. The current of each system with different power converter has a same tendency and the voltage which rectifying device of dual mode power converter endures is reduced in half by comparison with that of power converter with one bridge rectifier. We found dual mode power converter can be applied to SFCL.

• Proceedings of the KIEE Conference
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• 2003.07a
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• pp.494-496
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• 2003

This paper analyses the operation characteristic of distance relay when the single line to ground occurs in underground power cable systems that reduction device of sheath circulating current is installed. To apply that reduction device to actual system, the change of line impedance calculated at relay point is also analysed by the connection type of SVLs and fault location, fault inception angle with the installation of reduction device of reactor or not.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.13 no.1
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• pp.48-53
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• 2017

We diagnosed the defect using the data obtained from the nuclear power plant simulator. In this paper, we diagnosed faults in the nuclear power plant system for discovery instead of the traditional single-component or device unit. We created the six fault scenarios and used a fault simulator to obtain the fault data. It was extracted pattern from acquired failure data. Neural network model was trained and simple pattern matching algorithm was applied. We presented a simulation result and confirmed that the applied algorithm works correctly.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2003.11a
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• pp.111-116
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• 2003

Recently, power-electronics equipments or machine that microprocessor is included and computers have been installed continuously in industrial process or region of electronics customer. So concern for power quality, especially sags has been increased. Because those equipments are very sensitive to sags. The sag is phenomenon that magnitude of load voltage temporarily decreases because of power system fault. If a certain equipment in industrial process have any trouble result from sag, it can cause utility to be charged for enormous economics loss. Therefore it need to analyze the characteristic of sag and then mitigation method for sags in distribution system in oder to increase reliability. This paper gives an overview of sags characteristic due to short circuit fault in distribution system and after a general discussion of the various forms mitigation, gives a sags mitigation method with concentrating on mitigation-device interface method, especially FCL that is Fault Current Limiter.

• Proceedings of the KIPE Conference
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• 2014.07a
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• pp.5-6
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• 2014

According to 2013 fire statistical yearbook in the National Emergency Management Agency, the main cause of an electrical fire are classified to short circuit fault, overload fault, electric leakage, partial disconnection, and joint/contact badness. The occurrence factor of fire is electric arc or spark accompanied with electrical faults. Residual Current Protective Devices(RCDs) of high sensitivity type used at single phase (220V) cut off earth leakage and overload but the RCDs can not cut off electric arc or spark to be a main cause of electrical fire. To be improved on such problem, this thesis is proposed to a auxiliary control device for RCD cut off electric arc or spark.

• The Transactions of the Korean Institute of Power Electronics
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• v.21 no.4
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• pp.335-342
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• 2016

This paper proposes an energy storage-assisted, series-connected module-integrated power conversion system that integrates a photovoltaic power conditioner and a charge balancing circuit. In conventional methods, a photovoltaic power conditioner and a cell-balancing circuit are needed for photovoltaic systems with energy storage devices, but they cause a complex configuration and high cost. Moreover, an imbalanced output voltage of the module-integrated converter for PV panels can be a result of partial shading. Partial shading can lead to the fault condition of the boost converter in shaded modules and high voltage stresses on the devices in other modules. To overcome these problems, a bidirectional buck-boost converter with an integrated magnetic device operating for a charge-balancing circuit is proposed. The proposed circuit has multiple secondary rectifiers with inductors sharing a single magnetic core, which works as an inductor for the main bidirectional charger/discharger of the energy storage. The secondary rectifiers operate as a cell-balancing circuit for both energy storage and the series-connected multiple outputs of the module-integrated converter. The operating principle of the cell-balancing power conversion circuit and the power stage design are presented and validated by PSIM simulation for analysis. A hardware prototype with equivalent photovoltaic modules is implemented for verification. The results verify that the modularized photovoltaic power conversion system in the output series with an energy storage successfully works with the proposed low-cost bidirectional buck-boost converter comprising a single magnetic device.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.1
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• pp.182-187
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• 2015

In the three-phase power system, when any one-phase or two-phases is open-phase, the unbalanced current flows and the single-phase power supplies to three-phase loads. Specially, motor coil and transformer coil receive over-current. As a result, great damage as well as electrical fire can occur to the power system. In order to improve these problems, this paper proposes that an open-phase detection device is designed by a new algorithm using electric potential difference between the resultant voltage of neutral point and ground, and a control circuit topology of open-phase protector is composed of highly efficient semiconductor devices. It improves response speed and reliability. The control algorithm circuit also operates the cut-off of a conventional residual current protective device (RCD) which flows an enforced leakage current to ground wire at open-phase accident. Furthermore, time delay circuit is added to prevent the incapable operation of open-phase protector about instantaneous open-phase not open-phase fault. The time delay circuit improves more reliability.

• Fire Science and Engineering
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• v.34 no.3
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• pp.43-48
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• 2020

The purpose of this study is to develop an earth leakage alarm circuit breaker, equipped with a leakage alarming function (JER-E2S, ETECKOREA Co., Korea), and to analyze its characteristics. The developed mechanism is exclusively used for single-phase and 220 V circuits, with a rated current of 32 A, 20 A, 20 A (for restrooms), 16 A, etc. It satisfies all characteristics of existing earth leakage circuit breakers (ELB). If a fire current, which is a resistive leakage current (Igr), flows through an electric line, the device detects the leakage current in real time and warns against the leakage through a blinking LED lamp. Since the developed device displays a tolerance to a capacitative leakage current (Igc) that inevitably occurs in LED lamps, communication devices, etc., it ensures a stable power supply. In addition, the earth leakage alarm circuit breaker protects against power failure due to a momentary ground fault. Therefore, it can supply power without the risk of the circuit breaker malfunctioning due to a momentary ground fault caused by water droplets, leaves, etc. Moreover, with a standby power of less than 0.1 W, the developed earth leakage alarm circuit breaker exhibits a power saving performance that is 3~8 times greater than that of other ELBs. Installation of approximately 10 earth leakage alarm circuit breakers in one apartment household, with an area of 120 ㎡, can save 2~5 kWh per month. Therefore, the developed earth leakage alarm breaker not only satisfies the characteristics of existing earth leakage breakers, but also exhibits outstanding power supply quality since it has the functions of electric fire prevention and malfunction prevention. Therefore, this device can innovatively contribute to electric fire prevention.