• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.8
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• pp.109-118
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• 2010

It is expected that distribution system, interconnected with wind turbines, would experience the voltage problem due to WT's output. But most papers just consider this problem using the simulation or the theory only. In this paper, we verify this problem through the measurement at the distribution system and wind turbine. We explain the method for voltage management at distribution system. And we verify that the voltage of D/L interconnected with WTs could not be maintained properly using pole transformer's tap only. We consider some method to solve this problem and we propose the installation of SVR(step voltage regulator). Finally we show this method's validity through the simulation.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.5
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• pp.145-151
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• 2010

Voltage unbalance is regarded as a power quality problem of significant at the user application. Although the voltages are quite well balanced at the transmission system, the voltage level of utilization can be unbalanced due to the unequal system impedances and the unequal distribution of single phase loads. Capacitor is generally used for power-factor compensation and reducing harmonics of non linear load with reactor. If voltage unbalance exists, current unbalance is generated and it will be reflected in the capacity variance. When the reactor and condenser are used at the same location, generally its trouble rate is high. And it is very important checking out that how the variance of voltage, current and capacity of condenser is proceeded by the voltage unbalance. In this paper, we calculated that voltage, current and capacity of condenser are within the tolerance limit of official regulations in the event of voltage unbalance with/without reactor.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.12 no.1
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• pp.35-44
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• 1998

In this paper, input LC filter design of diode rectifiers considering filter V A rating reduction has been propoesd. It consisted of an input LC parallel resonent tank whose inductor and capacitor values are se$.$ lected so that the input filter presents an infinite impedance to harmonic input ac current component. The operation of proposed input filter has been analyzed in detail under steady state conditions. Performance evaluation and related design data have been provided on Per Unit basis for the proper implementation of diode rectification system. Finally, Detailed input and output current analysis has shown that the proposed input filter yield high quality input ac current waveforms, in particular, high input power factor values and more reliabilty which reducing the V A rating of passive components as compared to the standard type LC filter.filter.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.15 no.2
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• pp.57-63
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• 2001

This paper analysed the characteristic of Power consumption at many type of Inverter controlled Elevator. Especially, this paper proposed the standard value of full load currents. For this propose, it was classified by the passenger capacity and manufacture company. As a result, it is found that (i) the value is between -3[A] and 7[A] in case of elevator. That means the full load currents was smaller than the standard value of conventional operation type (ii) the value is between 0.5[kVA] and 3[kVA] in case of Power transformer. That means the transformer capacity was smaller than the standard value of conventional operation type. it was classified by the passenger capacity at inverter controlled elevator in apartment Also, to guarantee the operation stop of inverter controlled elevator, this paper proposed the redundancy method of electrical installations. the redundancy method is (i) 2 line service system and (ii) 2 distribution line system.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.2
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• pp.64-70
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• 2007

A voltage drop in the electrical circuit must be unavoidable. The voltage drop in the electrical circuit means a loss of heat. The heat lost would change the characteristics of the insulator and thus, the insulating performance would be towered resulting in electric leakage, electric shock, power failure, fire and other accidents. Hence, an optimized design against the voltage drop in the electrical circuit must be an important factor determining safety and economy of electrical facilities. This study analyzed the effects of voltage drop on the electrical circuit for such low-voltage electrical facilities requiring the public safety foremost and subject to multi-distributed random loads as street lamps, buildings and subway stations, and thereupon, developed an optimized voltage drop computation program to enhance safety and economy of those electrical facilities.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.12
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• pp.36-46
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• 2008

This paper is to study on the Construction of Test circuit and Unification of Experiment Method for high voltage gas-insulated load switch using high power testing system The high power testing system is a equipment to verify electrical and mechanical performance on electrical product. The system consist of short-circuit generator, back-up breaker, making switch, impedance, high voltage transformer, low voltage transformer, measuring and protection system, etc. Using this system, we can test related to high power, for example, short-time current test, active load Current test, magnetizing Current test, capacitive current test, closed loop current test, etc. Standards of high voltage gas-insulated load switch that is in use domestic distribution line are ES 5925-0002, IEC 60265-1, IEC 62271-1 and IEEE C 37.74, etc. In this paper, we standardized on the test procedure, organization of test circuit and analysis of measured data prescribed many difference standards, and applied this test method to 600[MVA] high power testing system. So that we can test the load switch satisfied standards.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.15 no.3
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• pp.67-73
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• 2001

This paper resents a developed measuring device of resistive leakage current and a fundamental discussion of deterioration diagnosis for Zinc Oxide(ZnO) arrester blocks. We have developed the leakage current detection device for ageing test and durability evaluation for ZnO arrester blocks. The resistive leakage current can be used as an indicator to discriminate whether the ZnO arrester blocks is in good state or in bad. The resistive leakage current measuring system with the compensation circuit was designed and fabricated. The sauce tests for ZnO arrester blocks were investigated by observing the resistive leakage current together with fast Fourier transform analysis. The proposed monitoring systems for the resistive leakage current can effectively be used to investigate the electrophysical properties of ZnO arrester blocks in laboratory and to develop the techniques of forecasting the deterioration of ZnO arresters in electric power systems.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.19 no.5
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• pp.94-102
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• 2005

This paper performs analysis the load patterns for the all the special days and studies the change of the load patterns for the last 15 years using Expert system based on the load record and the weather condition record. The Expert system is one of the four major load forecasting methods of the power system And it is used for forecasting. loads of the special days based on the Know-how of the load forecasting Experts. After the author simulates the load forecasting using hourly relative factors of the load patterns based on the past load records, there is considerable improved effect. The average errors of past 5 days load forecasting of lunar New Year's Day (year 2002 and 2003) is $3.23{[\%]}$. Using the new method the author forecast loads of the lunar new year's days (the year 2005) and it shows only $1.78{[\%]}$ error. A field manual for the load forecast can be made using proposed method. The authors expect this article could give a guidance to those who wish to be load forecast expert.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.19 no.8
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• pp.150-157
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• 2005

This paper presents the simulation modeling and analysis of variable wind speed turbine system(VWTS) using the doubly fed induction generator(DFIG) connected the back to back converter system in the rotor side. In the simulation, using the model system which has the 660[kW] rated power, blade control and the dual converter system are modeled for verifying the control characteristics. The VWTS is controlled by the optimal pitch angle for maximum output power under the rated wind speed, and for the rated output power over the rated wind speed. And also power factor is controlled by the reactive power. To verify the effectiveness of the proposed method, simulation results are compared with the actual data from the V47 VWTS located in Hangwon wind farm in Jeju-Do. According to the comparison of these results, this method shows excellent performance.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.12
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• pp.106-114
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• 2009

This paper addresses unit commitment for microgrid optimization including renewable energy sources, working under deregulated power market. As microgrid supplies both heat and electricity for consumer, operational optimization must be done to meet their demand economically. So renewable energy sources are considered to be negative load, and batteries are used as the load flattening device to raise possibly operational function. In the state of solution, the program is developed to solve out the maximum profit of microgrid using dynamic programming method. Finally, its validity is verified through case study in isolation mode and interconnected mode. The S/W will be used to operate microgrid economically after the market of microgrid is formed.