• Proceedings of the KIEE Conference
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• 2006.04b
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• pp.244-246
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• 2006

This paper deals with an analysis of SCR thyristor switching pattern for a power quality disturbance generator with phase jump function. The proposed generator can be applied to the performance test of custom power devices. Voltage sag, swell, outage, unbalance and phase jump after outage are provided by the generator. The phase jump operating principle of the generator is described and analysed. Especially, a proper switching of the SCR thyristors for the proposed generator is important to guarantee the system reliability. Therefore the switching patterns for the thyristors in each made were analysed.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.57 no.4
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• pp.383-387
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• 2008

This paper analyzes the operation characteristics of a self excited induction generator with Steinmetz connection. For this analysis, the symmetrical components analysis is used to obtain the related expressions and the excitation capacitance and the magnetizing reactance are determined in turn by the condition of self excitation which includes the input impedance of the generator as viewed across load terminals. Two simultaneous equations of the condition of self excitation itself are solved by using the real and imaginary function in an application software. This method is applied to simulate the operation characteristics when the generator is driven at rated speed and the specified excitation capacitor is connected across the lagging phase. The results show that better operation characteristics except generated frequency are obtained by using relatively large excitation capacitance and resistive load.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.63 no.4
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• pp.322-326
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• 2014

Recently, the LOE(loss of excitation) incidents are occurred in domestic synchronous generator frequently, the synchronous generator protection system has been much attention for the LOE protection of the incidents that threats synchronous generators and power systems. This paper was showed the characteristics and practices of distance relay that widely used LOE protection relaying in generator. Firstly, the operating characteristics and the impedance locus for LOE of the generator protection were introduced. Even if the conventional simulation program is used for modeling, but it is difficult to implement a LOE modeling and simulation of synchronous generator. So, the LOE relay operation data collected from thermal power plant and nuclear power plant in real fields were analyzed. By reviewing the applications of GE Mho relays, the reliability of LOE for synchronous generator protection in domestic were improved.

• Journal of Advanced Marine Engineering and Technology
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• v.26 no.3
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• pp.313-319
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• 2002

Since the oil crisis in 1970, a great deal of effort has been made to develop automatic electric load sharing systems as a part of the efforts to save energy. A large scale electric generating system composes more than two generators whose characteristics may be different. When such a system is operated individually or in parallel, the lagrange multiplier's method has difficulty in achieving optimal load distribution because generators usually have the limitations of the operating range with inequality constraints. Therefore, a suitable operating mode of generators has to be decided according to the selection of the generators to meet electric power requirements at the minimum cost. In this study, a method which solves the optimal electric load distribution problem using the dynamic programming technique is proposed. This study also shows that the dynamic programming method has an advantage in dealing with the optimal load distribution problem under the limitations of the operating range with inequality constraints including generator operation mode. In this study, generator operating cost curve of second order equation by shop trial test results of diesel generators are used. The results indicate that the proposed method can be applied to the ship's electric generating system.

• Proceedings of the KIPE Conference
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• 2004.07a
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• pp.141-143
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• 2004

Distributed generation(DG) using microturbine will be adopted widely because of its various usages and merits such as high heat efficiency, environmental-friendliness. Commercialized DG using microtubine that rotates up to $60,000\~100,000[rpm]$ converters mechanical power to electricity by permanent magnet synchronous machine. This paper presents comparative test and simulation results of PMSM as generator. Test was done by diode rectifier and inverter. Parameters used in the simulation are driven from FEM analysis. Under various speed and load conditions, V-I characteristics matches well and it suggests the possibility of high speed PMSM as generator. DG operating at stand alone and grid connection mode will be developed.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.3B no.3
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• pp.139-146
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• 2003

In this paper, the steady-state operating performance analysis for the three-phase squirrel cage rotor self-excited induction generator (SEIG) driven by a variable-speed prime mover (VSPM) in addition to a constant-speed prime mover (CSPM) is presented on the basis of an effective algorithm based on its frequency-domain equivalent circuit. The operating characteristics of the three-phase SEIG coupled by a VSPM and/or a CSPM are evaluated on line processing under the condition of the electrical passive load parameters variations with simple and efficient computation processing procedure in unregulated voltage control loop scheme. A three-phase SEIG prototype setup with a VSPM as well as a CSPM is implemented for the small-scale clean renewable and alternative energy utilizations. The experimental operating characteristic results are illustrated and give good agreements with the simulation ones.

• 한국신재생에너지학회:학술대회논문집
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• 2006.06a
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• pp.253-256
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• 2006

This paper shows operating characteristics of DFIG(Double Fed Induction Generator) for wind turbine. The back to back PWM voltage-fed inverter connected between the rotor and grid network operated sub and super-synchronous operating mode, and the vector-controlled DFIG enables the decoupling between active and reactive power as well as between torque and power factor. This paper is validated by simulations and experimental results.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.460_461
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• 2009

This paper analyzes the steady state characteristics for variable speed wind power system with doubly-fed induction generator(DFIG). This paper explains the equivalent circuit and phasor diagram of DFIG for different operating conditions. It also simulates the torque-slip characteristics with respect to changes of different parameters. Simulation results show the torque-slip characteristics, stator power factor-rotor voltage and stator current-rotor voltage.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.63 no.2
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• pp.55-60
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• 2014

In general, A synchronous generator is higher than the voltage stability of the induction generator. However, induction generator has many advantages rather than a synchronous generator in terms of price and maintenance. So, coverage rate of the induction generator is gradually increasing in small hydroelectric power station rather than 1000kW recently. In order to increase the penetration of induction generator, pre-analysis of the operation of the generator is needed. In this study, we analyzed for the problems that occur when synchronous generator and induction generator of 1500kW is connected to the distribution system.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.5
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• pp.632-638
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• 2013

In this study, we described voltage fluctuation characteristics of distribution line during starting and normal operation condition of the small hydro generators. Based on these theories, we scrutinized the starting and operating characteristics of induction generators installed in two small hydro power plants that is connected to the distribution line and researched necessary factors when selecting the generator type. The type of turbines and capacity of generators are different. One is below 1,000kW and the other is above 1,000kW. Two generators are tested during starting, and it acts as motor not generator at the instant that the machine is connected to the grid. After connecting to the grid, the machine rotates above synchronous speed before converting to the generator mode. Therefore the characteristic of the generator during starting is same as it of motor.