• Proceedings of the KIEE Conference
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• 1994.07a
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• pp.444-446
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• 1994

This paper describes the design of a digital multifunction controller for the intelligent high voltage customer switchboard and proposes a relaying algorithm for high impedance faults using back-propagation neural network. The hardware design uses the three microprocessors and global memory architecture to achive real time operation and control 4 feeders. The controller uses a 64-point radix-4 DIF FFT algorithm to measure the harmonic and relay parameters. Synthesized fault current waveforms are used to train and test the back - propagation network.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2007.05a
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• pp.203-205
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• 2007

A method is proposed in this paper to determine the harmonic contributions of a customer at the point of common coupling. The method can quantify customer and utility responsibilities for limit violations caused by either harmonic source changes or harmonic impedance changes. It can be implemented in current power quality monitors and digital revenue meters. The method is comparison of measurement phase angles between harmonic voltage and current. The proposed method has been applied to the test system. The study results have indicated the accuracy of harmonic injection and emission for customer and utility.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.561-562
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• 2007

A method is proposed in this paper to determine the harmonic contributions of a customer at the point of common coupling. The method can quantify customer and utility responsibilities for limit violations caused by either harmonic source changes or harmonic impedance changes. It can be implemented in current power quality monitors and digital revenue meters. The method is comparison of measurement phase angles between harmonic voltage and current. The proposed method has been applied to the test system. The study results have indicated the accuracy of harmonic injection and emission for customer and utility.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2004.11a
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• pp.115-120
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• 2004

Most of the LV customer have been applied the distribution system of 3-phase four wire system because of its advantage of supplying both of 1-phase & 3-phase loads simultaneously. Due to its structural simplicity, it is more convenient for use rather than the conventional separated scheme. But uneven load distribution or unclean voltage quality has occurred various problems such as do-rating, losses increase and vibration, etc. In this paper, voltage, current and power waveform in the actual fields have measured and analyzed in relation with internationally allowable voltage unbalance limits and compared the current unbalance factor with the load unbalance factor.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2004.05a
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• pp.353-357
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• 2004

This paper presents the result of survey of case study for harmonics in electrical installations of buildings. Recently, many power electronic equipments(power converter, computers, air conditioners electronic ballasts for fluorescent lamps and so on) are used in office buildings, and harmonic current from them influence the other equipments in a distribution line. Notably, voltage distortion or voltage harmonics may approach or exceed is allowable level in power distribution system. Individual electric power consumers and end-users and responsible for reducing current harmonics while companies or utilities are responsible for reducing voltage harmonics at the point of common coupling in distribution system. As for harmonics, which one of the electric power qualities, it becomes important to obtain harmonic voltage/current distribution of the power system precisely because the use of power electronic apparatus in increasing. To suppress harmonics in electrical ins tallations of buildings, one of many methods suggest that resonance frequencies are controlled by modulating the capacities of high-voltage customer's capacitors.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.2
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• pp.1355-1363
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• 2015

In order to maintain customer voltage within allowable limit($220{\pm}13V$), tap operation of SVR(step voltage regulator) installed in primary feeder could be carried out according to the scheduled delay time(30 sec) of SVR. However, the compensation of BESS(battery energy storage system) is being required because the customer voltages during the delay time of SVR have a difficultly to maintain within allowable limit when PV system is interconnected with primary feeder. Therefore, this paper presents modeling of SVR to regulate voltage with the LDC(line drop compensation) method and modeling of BESS to control active and reactive power bi-directionally. And also, this paper proposes the coordination control modeling between BESS and SVR in order to overcome voltage problems in distribution system. From the simulation results based on the modeling with the PSCAD/EMTDC, it is confirmed that proposed modeling is practical tool for voltage regulation analysis in distribution system.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.4
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• pp.54-61
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• 2015

Recently, DC-based power system is being paid attention as the solution for energy efficiency. As the example, HVDC (High Voltage DC) transmission system is utilized in the real power system. On the other hand, researches on LVDC (Low Voltage DC) distribution system, which are including digital loads, are not enough. In this paper, reliability in LVDC distribution system is analyzed according to the specific characteristics such as the arrangement of DC/DC converters and the number of poles. Furthermore, power quality is also taken account of since LVDC distribution system includes multiple sensitive loads and electric power converters. In order to achieve this, LVDC distribution systems are modeled using ElectroMagnetic Transient Program (EMTP) and both the minimal cut-set method and Customer Interruption Cost (CIC) are used in the reliability analysis.

• The Journal of the Korea institute of electronic communication sciences
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• v.3 no.4
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• pp.260-265
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• 2008

The arc-fault occurring in the customer system becomes the direct cause of electric fire. However, it is very difficult to identify the arc-fault using the existing fault detection mechanism because the magnitude of the fault current is very small. Accordingly, this paper analyzes the causes of arc fault and designs the basic detection mechanism of arc fault. And then, it proposes an signal processing-based arc-fault determination methodology which can enhance the of accuracy of the arc-fault determination by applying DFT/DWT to the voltage and current waveform. Finally, this paper showed the application methodology of the proposed signal processing based fault determination method by applying and analyzing DFT/DWT to an high voltage in-rush current waveform.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.9
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• pp.1523-1529
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• 2010

This paper describes the distribution power system econimical PQMS(Power quality monitoring system) of Utility. Recently, the korea power quality standard has been established based on the IEC Std. By IEC Std., the power quality assessment point is measured in PCC(Point of common coupling). In this case, the utility has to construct PQM system in all customer PCC point and the PQ meter cost would be very high in order to acquire the suitable data. Also the distribution system would be encounter the communication overload problem due to the huge data. Accordingly the utilities could not apply to PQM system in the distribution power system by the cost and communication problem. In this paper, the proposed economical PQMS has the voltage and current signal reiteration function and FFT operation function is transferred the server. Also the voltage and current measurement channels are minimized by a classified substation construction.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.56 no.3
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• pp.123-128
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• 2007

Hydro power supplies no pollution energy, mainly induction generator has been applied at the small capacity power station. The generating power of small hydro-electric power station connects on the 22.9kV distribution system or low voltage system in the case of three-phase four-wire supply system. There are side effects of various kinds in the 3-three phase 4-wire distribution system mixing 1-phase load and 3-phase load. This system generates the voltage unbalance by unbalanced load operating condition. They have various serious effects on generator and connection system. In this paper, we analyzed what kind of operation characteristic are happened in the induction generator by customer load variation at the 3-three phase 4-wire distribution system.