• 전기학회논문지
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• 제57권10호
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• pp.1726-1730
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• 2008

In this paper, the application schemes for coordinated control system of multiple FACTS were presented to enhance the voltage stability around the metropolitan areas. In order to coordinated control of FACTS devices, f-V analysis method which is one of the indices for voltage stability was performed with real time network data which is transferred from SCADA/EMS system. If the system is unstable after contingencies, the new operation set-point of FACTS would be determined using bus sensitivity from tangent vector at voltage instability point. Otherwise, we would determine the new operation set-point of FACTS for considering economical operation, like as active power loss minimization using Optimal Power Flow algorithm. In simulation, the SCADA/EMS 2007's data are used for studying the coordinated control algorithm of multiple FACTS devices that is installed or will be installed in KOREA power system

• Journal of Electrical Engineering and Technology
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• 제5권2호
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• pp.179-190
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• 2010

This paper describes a new stochastic heuristic algorithm in engineering problem optimization especially in power system applications. An improved particle swarm optimization (PSO) called adaptive particle swarm optimization (APSO), mixed with simulated annealing (SA), is introduced and referred to as APSO-SA. This algorithm uses a novel PSO algorithm (APSO) to increase the convergence rate and incorporate the ability of SA to avoid being trapped in a local optimum. The APSO-SA algorithm efficiency is verified using some benchmark functions. This paper presents the application of APSO-SA to find the optimal location, type and size of flexible AC transmission system devices. Two types of FACTS devices, the thyristor controlled series capacitor (TCSC) and the static VAR compensator (SVC), are considered. The main objectives of the presented method are increasing the voltage stability index and over load factor, decreasing the cost of investment and total real power losses in the power system. In this regard, two cases are considered: single-type devices (same type of FACTS devices) and multi-type devices (combination of TCSC, SVC). Using the proposed method, the locations, type and sizes of FACTS devices are obtained to reach the optimal objective function. The APSO-SA is used to solve the above non.linear programming optimization problem for better accuracy and fast convergence and its results are compared with results of conventional PSO. The presented method expands the search space, improves performance and accelerates to the speed convergence, in comparison with the conventional PSO algorithm. The optimization results are compared with the standard PSO method. This comparison confirms the efficiency and validity of the proposed method. The proposed approach is examined and tested on IEEE 14 bus systems by MATLAB software. Numerical results demonstrate that the APSO-SA is fast and has a much lower computational cost.

• 대한전기학회논문지:전력기술부문A
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• 제55권7호
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• pp.281-289
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• 2006

Advanced controllers among Flexible AC Transmission System(FACTS) devices employ self-commutated switching converters, VSI (Voltage Sourced Inverters), as the synchronous voltage source. Such controllers are SSSC (Static Synchronous Series Compensator), STATCOM (Static Synchronous Compensator) and UPFC (Unified Power Flow Controller). UPFC is series-shunt combined controller. Its series and shunt inverters can be modeled as SSSC and STATCOM but the dependant relation between the inverters is very complex. For that reason, the complexity makes it difficult to develop the UPFC model by simply combining the SSSC and STATOM models when we apply the model for conventional power system dynamic simulation algorithm. Therefore, we need each relevant models of VSI type FACTS devices for power system analysis. This paper proposes a modeling approach which can be applied to modeling of VSI type FACTS devices. The proposed method using Newton-type current injection method can be used to make UPFC, SSSC, and STATCOM models. The proposed models are used for 2-area test system simulation, and the results verify their effectiveness.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 C
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• pp.1026-1028
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• 1999

In recent deregulation and competitive power market environment, electric utilities plan and operate their systems for economic benefit with secure system condition. Therefore, implementation of Flexible AC Transmission Systems (FACTS) devices can be planned for the efficient utilization of the present system facility. This paper presents a technique to solve the problem about optimal allocation of FACTS devices far the purpose of enhanced system operation.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 추계학술대회 논문집 학회본부A
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• pp.256-258
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• 1998

This paper presents a control system design for the UPFC of FACTS devices by optimal control scheme to enhance small-signal stability in the Power system. The feature of this UPFC controller is coordinated with generator exciter controller(AVR, PSS) to improve the total Power system stability and performance.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 추계학술대회 논문집 학회본부 B
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• pp.229-231
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• 2000

Precision control technologies are required for Lithography devices. The Linear BLDC Motor is used for operations of the stage. The stage is installed in Lithography devices. The stage is basically controlled though three directions (x, y, z axes). This paper presents precision control technologies of the Linear BLDC Motor (only one axes) by using computer simulations. We will plan that real systems is made and tested.

• Journal of Electrical Engineering and Technology
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• 제8권1호
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• pp.31-39
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• 2013

Proper installation of Flexible AC Transmission Systems (FACTS) devices in existing transmission networks can enable power systems to accommodate more power transfer with less network expansion cost. The problem to maximize transmission system loadability by determining optimal locations and settings for installations of two types of FACTS devices, namely static var compensator (SVC) and thyristor controlled series compensator (TCSC), is formulated as a mixed discrete-continuous nonlinear optimization problem (MDCP). For solving the MDCP, in the paper, the proposed method with fitness sharing technique involved in the updating process of the particle swarm optimization (PSO) algorithm, can diversify the particles over the search regions as much as possible, making it possible to achieve the optimal solution with a big probability. The modified IEEE-14 bus network and a practical power system are used to validate the proposed method.

• Journal of Electrical Engineering and Technology
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• 제1권2호
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• pp.129-136
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• 2006

This paper proposes a probabilistic evaluation for the transient stability of electrical power systems incorporating FACTS devices. The uncertainties of the fault location and relay operation time play important keys in power system instability evaluation. The TCSC and SVC are employed for the reduction of system instability probability. This method is demonstrated by the WSCC test system and the results are compared with and without FACTS by means of Monte Carlo simulation.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 A
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• pp.198-199
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• 2006

FACTS(Flexible AC Transmission System) 기기들은 전력계통의 경제적이고 안정적인 운용과 제어에 더 많은 유연성을 제공할 수 있다. 그러나 이러한 FACTS 기기들은 기존의 전력 계통 설비들과는 달리 그 특성이 매우 비선형적이고 복잡하기 때문에 기존 전력 계통의 동적 시뮬레이션 알고리즘에 적용시키는 것이 매우 어렵다. 이러한 어려움을 해결하기 위하여 전압원 인버터(Voltage Sourced Inverter) 형태의 FACTS 기기를 병렬 형태로 주입되는 전류로 등가화 하여 기존의 시뮬레이션 알고리즘에 적용하는 방법이 제안되었다. 본 논문에서는 이 전류 주입형 기법을 이용하여 다수의 FACTS 기기들이 설치된 계통의 동적 안정도 해석 방법을 제안한다. 제안된 방법은 서로 다른 형태의 FACTS 기기들이 설치된 경우에도 적용될 수 있으며 이를 이용하여 서로 다른 FACTS 모델들 간의 조합에 의한 계통의 안정도 변화를 사례연구를 통하여 보일 것이다.

• Journal of Electrical Engineering and Technology
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• 제6권1호
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• pp.14-24
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• 2011

In order to facilitate the electricity market operation and trade in the restructured environment, ample transmission capability should be provided to satisfy the demand of increasing power transactions. The conflict of this requirement and the restrictions on the transmission expansion in the restructured electricity market has motivated the development of methodologies to enhance the available transfer capability (ATC) of existing transmission grids. The insertion of flexible AC transmission System (FACTS) devices in electrical systems seems to be a promising strategy to enhance single area ATC and multi-area ATC. In this paper, the viability and technical merits of boosting single area ATC and multi-area ATC using Thyristor controlled series compensator (TCSC), static VAR compensator (SVC) and unified power flow controller (UPFC) in single device and multi-type three similar and different device combinations are analyzed. Particle swarm optimization (PSO) algorithm is employed to obtain the optimal settings of FACTS devices. The installation cost is also calculated. The study has been carried out on IEEE 30 bus and IEEE 118 bus systems for the selected bilateral, multilateral and area wise transactions.