• Proceedings of the KIEE Conference
• /
• 1997.07c
• /
• pp.1127-1129
• /
• 1997

In this paper, we developed to artificial neural network for load characteristic identification of power system. We can acquire active power and reactive power of individual load depending on the variation of voltage and frequency from the experimentation of a dynamic characteristic of load. The data of the experimental results were be used in learning of ANN. A proposed ANN model is applied to analyze the transient stability. To demonstrate the propriety of the power system transient stability with load model using ANN, the simulation of the two-machine five-bus system is carried out.

• Proceedings of the KIEE Conference
• /
• 2008.07a
• /
• pp.189-1-190-1
• /
• 2008

A high temperature superconducting(HTS) power cable is available for high capacity current in normal condition. But resistance was appeared to operate unbalance load by thermal current characteristic. This characteristic of HTS power cable used to design for unstated condition. And than, It used to understand and analyze characteristic of power cable thermal and critical current. This study appeared that quench resistance reason from shield and former current rise to superconductor(SC) current. The resistance of SC occurred that the cable temperature rise to fault current after decreased critical current. The quench resistance of SC increased in temperature or decreased in critical current. So the quench resistance of SC correlated with resistance of both shield and former current. It need to sufficiently influenced the parameters of HTS cable design.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.65 no.3
• /
• pp.520-525
• /
• 2016

In this paper, Characteristic of power conversion unit of a railway vehicles according to contact loss in feeding system that applied impedance of rigid conductor is analyzed. It applied impedance of rigid bar in modeling of electric railway system. Railway vehicles are performed of modeling based on the performance of the electric railway vehicle. Effects of the contact loss in the power conversion unit were analyzed via main transformer of railway vehicle, the input and output voltage characteristics of the converter through contact loss was generated after linking the vehicle with feeding system.

• Journal of Advanced Marine Engineering and Technology
• /
• v.33 no.8
• /
• pp.1226-1231
• /
• 2009

In this paper, a solar-wind hybrid system is decsribed for Stand-Alone(SA) power generation system. Mostly SA power generation system for ocean facilities composes a solar system. Normally, the output power of solar system is decreased with weather condition as cloudy and rainy. Solar-wind hybrid system can be operated as complement system each other. In this paper, the characteristic simulation of solar and wind is performed by LabVIEW. The hybrid power generation system is designed according to simulation results, and is tested for checking the complement characteristic.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.16 no.4
• /
• pp.661-668
• /
• 2012

A coaxial-cable impedance transformer that can be used in high power and wideband frequency range is an arbitrary impedance transformation ratio by an additional coaxial cable. The coaxial-cable impedance transformer to be 50-${\Omega}$ to 25-${\Omega}$ impedance transformation ratio is easily operated an wideband power divider by connecting two 50-${\Omega}$ lines at 25-${\Omega}$ impedance point. This wideband power divider has a poor output matching characteristic and a poor isolation characteristic between two output ports. In this paper, it proposes a coaxial-cable power divider to be a good output matching and isolation characteristics as it uses the singly terminated filter design theory. The odd-mode operation characteristic of the suggested power divider to use singly terminated low pass filter coefficient due to matching order and ripple value is examined by ADS program. And, it fabricates and measures the operation characteristic of 2-way power divider with 2nd-order and 4th-order matching circuit.

• Journal of The Institute of Information and Telecommunication Facilities Engineering
• /
• v.2 no.4
• /
• pp.42-51
• /
• 2003

In this paper, we are going to analyze on relation of an output spectrum along phase distortion of power amplifier in wireless LAN system, and then considered an ACPR characteristic of power amplifier and consideration of an OFDM method for this. Also, we did implementation for OFDM modulation and transmission section of an IEEE 802.11a standard to have transmission speed of the maximum 54Mbps in order to know an OFDM modulation method and relation of non-linear characteristic of power amplifier. The non-linear characteristic of power amplifier did modeling with AM-to-AM and AM-to-PM, and we analyzed an output spectrum characteristic along phase distortion composed input signal supply for power amplifier. When output spectrum analysis results phase distortion increased, and an AM-to-PM characteristic of power amplifier in 5 degrees, the output spectrum was satisfied with a demand spectrum in P1 dB, but 10-20 degrees were able to confirm what cannot be satisfied with a demand spectrum in phase distortion. Also, an output spectrum of power amplifier by frequency re-growth generated by a non-linear characteristic of power amplifier did not satisfied in P1dE. therefore, a back-off value was requested according to an AM-to-PM distortion degree, and smaller back-off value were able to know what demand became in case of modulation section that used OFDM.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.14 no.3
• /
• pp.226-232
• /
• 2003

In this paper, design rule of power island is studied. Power island have a defect that increase transfer noise when each power bus structure is resonant. So, in this paper, resonances are suppressed for various noise source positions and in order to improve noise characteristics, it is suggested EGI in order to improve noise characteristic. At the simulation result, the least resonance is showed for various noise source position and transfer impedance with power bus resonance is reduced about 11 $\Omega$ by EGI.

• The Transactions of the Korean Institute of Electrical Engineers
• /
• v.45 no.4
• /
• pp.474-483
• /
• 1996

In this paper, as a part of the method improving stability, the load-flow calculation in D.C. power system and the models for stability analysis are studied with A.C-D.C. interconnected power systems transmission performed. Moreover, the theory is established in relation to each control method of D.C. power systems. Then the stability of A.C-D.C.interconnected power systems is compared and considered by the way of dividing the operating control method of the rectifier inverter converter into ACR-AVR, APR-A.gamma.R, A.alpha.R-ACR. The dynamics characteristic of terminal voltage, frequency, active-reactive power and rotor angle of the generator with disturbances and load fluctuations is considered. In addition, the characteristic of direct voltage, direct current, power and control systems. From this the comparative analysis of the direct current control method, the possibility of the stability analysis of A.C.-D.C. interconnected power system is considered. (author). refs., figs., tabs.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.61 no.10
• /
• pp.1399-1411
• /
• 2012

The grid frequency is controlled cooperatively by the governor of the Turbine-Generator and the automatic generation controller(AGC) of the KPX(Korea Power Exchange). It is a basic requirement that the reliability of the governor is verified to enhance the power system stability but it is not easy to confirm the response characteristics of the governor because all generators are operated in the grid system that has the constant voltage and frequency. Therefore, it is necessary to study a new test method in order to examine the governor dynamic characteristic in the similar fault conditions. A study has shown that it is verified to simulate the turbine-generator power control system, the governor response characteristic under limited conditions and contribution of AGC with the gas turbine generator simulation model as well as demonstrate the dynamic response of the governor with the developed governor dynamic characteristic tester based on digital controller while the turbine-generator is connected to the grid system. This tester is constructed by the built-in functions of the turbine-generator main controller. In this treatise, the theoretical background, development method and the results of both simulations and demonstrations are described as another way to verify the turbine-generator governor dynamic characteristics.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.6 no.1
• /
• pp.82-89
• /
• 2001

This paper proposes several methods to analyze dynamic and static characteristics of HVDC inverter system. The characteristic analysis is essential of the controller and filter design of the HVDC inverter system. Dynamic characteristic can be analyzed with EMTP simulation and static characteristic can be obtained by solving newly proposed load flow equation which includes the filter and load characteristic. New simple per-phase-equivalent circuit is also proposed. In this circuit, HVDC inverter is considered as a current source depending on the on-off status of switch. Dynamic and static characteristic can be analyzed by the proposed per-phase-equivalent circuit. For the optimal filter design, various performance criteria are proposed. The performance index, based on the per-phase-equivalent circuit, is calculated. Voltage harmonics and filter power loss are selected as criteria. Optimization procedure is explained to find optimal passive filter parameters.