• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 1991년도 추계학술발표회논문집
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• pp.80-83
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• 1991

The need of UPS (Uninterruptible Power Sup-ply) system is dramatically increasing with the increased use of computers, telecommunica-tion system, building automation system, and office automation system in office buildings. The consequence of the power failure is very disas trous in intelligent office buil-dings. Thus, the nucessity of large scale UPS system with generations of large scale UPS system with generator is increasing. In this study, the configurations of large scale UPS system are reviewed and analyzed. The design guide and technical considerations of high reliability system are presented.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 A
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• pp.134-135
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• 2003

Abstract in case of the small scale power system separated from large scale power system N-2 contingency, the Over excitation, Under Frequency and Power swing Tripping Relay operate depending on unbalance Of Generation and Load. and then we studied and measured the angle and frequency deviation between generators. moreover, we compared real fault example with simulation results.

• Journal of Electrical Engineering and Technology
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• 제9권2호
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• pp.399-405
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• 2014

For stable integration of large-scale wind farms, integration standards (Grid codes) have been proposed by the system operator. In particular, voltage control of large-scale wind farms is gradually becoming important because of the increasing size of individual wind farms. Among the various voltage control methods, Secondary Voltage Control (SVC) is a method that can control the reactive power reserve of a control area uniformly. This paper proposes hybrid SVC when a large-scale wind farm is integrated into the power grid. Using SVC, the burden of a wind turbine converter for generating reactive power can be reduced. To prove the effectiveness of the proposed strategy, a simulation study is carried out for the Jeju system. The proposed strategy can improve the voltage conditions and reactive power reserve with this hybrid SVC.

• 전기학회논문지
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• 제65권5호
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• pp.711-717
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• 2016

Recently, fuel cell generation system with high energy efficiency and low CO2 emission is energetically interconnected with distribution power system. Especially, MCFC(molten carbonate fuel cell) operating at high temperature conditions is commercialized and installed as a form of large scale power generation system. However, it is reported that power system disturbances such as harmonic distortion, surge phenomenon, unbalance current, EMI(Electromagnetic Interference), EMC (Electromagnetic Compatibility) and so on, have caused several problems including malfunction of protection device and damage of control devices in the large scale FCGS(Fuel Cell Generation System). Under these circumstances, this paper proposes countermeasure algorithms to prevent power system disturbances based on the modelling of PSCAD/EMTDC and P-SIM software. From the simulation results, it is confirmed that proposed algorithms are useful method for the stable operation of a large scale FCGS.

• 전력전자학회논문지
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• 제14권5호
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• pp.365-371
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• 2009

국내에서는 풍력 발전 기술 집약에 전력하고 있지만 풍력 발전 단지에 대한 운영 경험은 매우 제한적이며, 연계 기준 수립에 대한 기초가 부족한 실정이다. 따라서 국내 계통의 특성을 고려한 연계 기준 및 최적 운영 방안 수립을 위하여 여러 국가에서 적용하고 있는 풍력 발전 단지의 연계기준 및 최적 운영 방안에 대한 검토가 필요하다. 이에 본 논문은 제주계통을 대상으로 한 모의를 통하여 대규모 풍력 발전 단지의 최적 운영 방안에 대한 필요성을 확인하고 제안한다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 추계학술대회 논문집
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• pp.982-986
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• 1996

The development of a high power BLDC servo system for a control of the large scale mechanical system is presented. Using DSP TMS320C30, a control unit which is suitable for motor drive system, is developed. Also, based on the developed control unit, BLDC drive system for the speed control is constructed. The algorithms of the vector control, current control, and speed control is implemented using TMS320C30 Software Development Tool. The developed high power BLDC motor drive system is applied to the large scale mechanical system and its feasibility is verified through the experimental results.

• KIEE International Transactions on Power Engineering
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• 제11A권4호
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• pp.33-38
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• 2001

The KEPS(KEPCO＇s Enhanced Power system Simulator) Real Time Digital Simulator(RTDS) is the largest real time power system simulator ever built. A power system which includes 320 (3-phase) buses and 90 generators has been modeled and run in real time. Since such large-scale systems were involved, it was not practical to validate them using non-real time electro-magnetic transient programs such as EMTDC™ or EMTP. Instead, the results of the real time electromagnetic transient simulation were validated by comparing to transient stability simulations run using PTI's PSS/E™ program. The comparison of results from the two programs is very good in almost all cases. However, as expected, some differences did exist and were investigated. The differences in the results were primarily traced to the fact that the electromagnetic transient solution algorithm provides more detail solutions and therefore greater accuracy than the transient stability algorithm. After finding very good comparison of results between RTDS Simulator and PSS/E, and after investigating the discrepancies found, KEPCO gained the necessary confidence to use the large-scale real time simulator to analyze and develop their power system.

• 한국태양에너지학회 논문집
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• 제31권1호
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• pp.8-14
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• 2011

Recently, a number of large-scale photovoltaic(PV) power generation system has been installed all over the world. Thus, in order to improve the system efficiency, the optimal design of the large-scale PV systems has become an important issue. DC cable loss of PV array is one of the design factors related to the system efficiency. This paper introduces the array design method of a 500kW Photovoltaic power plant. Three types of the PV array are suggested. Also, string cables, sub-array cables and array cables are designed within 1% of voltage drop in the line, and the DC cable losses are analyzed. The results of this paper show that the DC cable loss of large-scale PV array can be reduced by adopting a proper sub-array design method.

• KEPCO Journal on Electric Power and Energy
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• 제5권3호
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• pp.229-233
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• 2019

Large-scale High Temperature Superconducting (HTS) wind power generators suffer from high electromagnetic force and high torque due to their high current density and low rotational speed. Therefore, the torque and Lorentz force of HTS wind power generators should be carefully investigated. In this paper, we proposed a Performance Evaluation System (PES) to physically test the structural stability of HTS coils with high torque before fabricating the generator. The PES is composed of the part of a pole-pair of the HTS generator for estimating the characteristic of the HTS coil. The 10 MW HTS generator and PES were analyzed using a 3D finite element method software. The performance of the HTS coil was evaluated by comparing the magnetic field distributions, the output power, and torque values of the 10 MW HTS generator and the PES. The magnetic flux densities, output power, and torque values of the HTS coils in the PES were the same as a pole-pair of the 10 MW HTS generator. Therefore, the PES-based evaluation method proposed in this paper can be used to estimate the critical characteristics of the HTS generator under high magnetic field and high torque before manufacturing the HTS wind turbines. These results will be used effectively to research and manufacture large-scale HTS wind turbine generators.

• International Journal of Control, Automation, and Systems
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• 제5권5호
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• pp.526-538
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• 2007

This paper presents a neural network based decentralized excitation controller design for large-scale power systems. The proposed controller design considers not only the dynamics of generators but also the algebraic constraints of the power flow equations. The control signals are calculated using only local signals. The transient stability and the coordination of the subsystem control activities are guaranteed through rigorous stability analysis. Neural networks in the controller design are used to approximate the unknown/imprecise dynamics of the local power system and the interconnections. All signals in the closed loop system are guaranteed to be uniformly ultimately bounded. To evaluate its performance, the proposed controller design is compared with conventional controllers optimized using particle swarm optimization. Simulations with a three-machine power system under different disturbances demonstrate the effectiveness of the proposed controller design.