• Journal of Electrical Engineering and Technology
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• 제8권3호
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• pp.428-435
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• 2013

Flexible AC Transmission System (FACTS) application study on enhancing the flexibility of AC power system has continued to make progress. A thyristor-controlled series capacitor (TCSC) is a useful FACTS device that can control the power flow by adjusting line impedances and minimize the loss of power flow and voltage drop in a transmission system by adjusting line impedances. Reduced power flow loss leads to increased loadability, low system loss, and improved stability of the power system. This study proposes the optimal location and compensation rate method for TCSCs, by considering both the power system loss and voltage drop of transmission systems. The proposed method applies a multi-objective function consisting of a minimizing function for power flow loss and voltage drop. The effectiveness of the proposed method is demonstrated using IEEE 14- and a 30-bus system.

• 전력전자학회논문지
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• 제6권3호
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• pp.291-298
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• 2001

본 논문은 차세대 FACTS(flexible AC Transmission Systems)기술인 UPFC(Unified Power Flow Controller)의 시뮬레이션을 다룬다. UPFC의 해석과 모델을 통하여 전력조류제어를 시뮬레이션 한다. 전력시스템의 과도상태 및 제어에 대한 시간영역 시뮬레이션 프로그램인 EMTDC(Electro-Magnetic Transients in DC systems)를 사용하여 전력조류제어인 유효전력 및 무효전력제어를 수행하고 더불어 모선입력전압의 크기를 제어한다. 시뮬레이션 결과를 통하여 UPFC의 제어성능을 검증한다.

• Journal of Electrical Engineering and Technology
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• 제5권4호
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• pp.522-529
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• 2010

Distance relay plays an important role in the protection of transmission lines. The application of flexible AC transmission systems (FACTS) devices, such as the static synchronous compensator (STATCOM), could affect the performance of the distance relay because of compensation effect. This paper analyzes the application of distance relay on the protection of a transmission line containing STATCOM. New setting principles for different protection zones are proposed based on this analysis. A typical 500 kV transmission system employing STATCOM is modeled using Matlab/Simulink. The impact of STATCOM on distance protection scheme is studied for different fault types, fault locations, and system configurations. Based on simulation results, the performance of distance relay is evaluated. The setting principle can be verified for the transmission line with STATCOM.

• 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.

• 대한전기학회논문지:전력기술부문A
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• 제52권3호
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• pp.165-172
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• 2003

This paper presents an operation scheme to enhance the power system security by applying FACTS on Power systems. Three main generic types of FACTS devices are suggested an illustrated. Flow congestions over lines have been solved by controlling active power of series-compensated FACTS devices and low voltages at buses have been solved by controlling reactive power of shunt-compensated FACTS devices. Especially, Especially, UPFC has been applied in both line congestion and low voltages. Two kinds of indices which indicate the power system security level related to line flow and bus voltage are utilized in this paper. They have been minimized to enhance the power system security level through the iterative method and the sensitivity vector of security index is derived to determine the direction to minimum. The proposed algorithm has been tested on the IEEE 57-bus system with FACTS devices in a normal condition and a line-faulted contingency.

• 전력전자학회논문지
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• 제5권4호
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• pp.377-385
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• 2000

본 논문에서는 국내 최초로 설치된 Custom Power기기인 배전용 STATCOM(STATic COMpensator)의 기기 신뢰성 확보를 위힌 기가 테스트 및 설계통 운전 분석결과를 보이고 있다. Custom Power는 유연송전시스템(FACTS : Flexible AC Transmission System)과 같이 교류전력계통을 제어함으로써 효율적이고 유연한 전력계통의 운용과 구성을 목적으로 한다. STATCOM은 Custom Power기기의 한 형태로 무효전력 보상, 전압조정, 그리고 전압 퓰리커 억제 등의 기능을 가진다. 본 논문에서는 STATCOM 시운전 결과 무효전력과 역률 보상에서 우수한 성능을 보임을 확인할 수 있다.

• Journal of Power Electronics
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• 제13권3호
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• pp.419-428
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• 2013

The modular multilevel cascade converter (MMCC) is a new family of multilevel power converters with modular realization and a cascaded pattern for submodules. The MMCC family can be classified by basic configurations and submodule types. One member of this family, the Hexverter, is configured as Double-Delta Full-Bridge (DDFB). It is a novel multilevel AC/AC converter with direct power conversion and comparatively fewer required components. It is appropriate for connecting two three-phase systems with different frequencies and driving an AC motor directly from a utility grid. This paper presents the dq model of a Hexverter with both of its AC systems by state-space representation, which then simplifies the continuous time-varying model into a periodic discrete time-invariant one. Then a generalized multivariable optimal control strategy for regulating the Hexverter's independent currents is developed. The resulting control structure can be adapted to other MMCCs and is flexible enough to include other control criterion while guaranteeing the original controller performance. The modeling method and control design are verified by simulation results.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 B
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• pp.646-651
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• 1996

This paper presents the study results of four transmission methods to enchance transmission capability. The four transmission methods studied were FACTS, HVDC, High Phase Order and new conductor material method. The study was Performed based on mid and long term KEPCO system in 2000 and 2006 year. Among them FACTS(Flexible AC Transmission System) is an exciting new field which holds great promise for improved utilization of AC transmission systems.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 추계학술대회 논문집 전력기술부문
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• pp.217-219
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• 2008

Among the Flexible AC Transmission Systems (FACTS) devices, Unified Power Flow Controller (UPFC) is considered as the most powerful and versatile one as it provides simultaneous, real time control of the transmission parameters, voltages, impedances, and phase angles which determine the power flow in AC transmission systems. This paper presents modelling of UPFC and describes its characteristics. The UPFC implemented in this paper is based on Sinusoidal Pulse Width Modulation (SPWM) and Electro-Magnetic Transients Program (EMTP)/ATPDraw is used to model and analyze it. The simulation results confirm advantages of UPFC in operational performance with respect to the steady state Power flow regulation and the transient stability control.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 A
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• pp.280-282
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• 2002

This paper presents the characteristics and Real Time Digital Simulator(RTDS) model for Seo-deagu Static Var Compensator(SVC) systems installed in 1999. SVC system is a power system controller using power electronics called Flexible AC Transmission Systems (FACTS). RTDS model for Seo-deagu SVC is developed and verified, we recognize to be essential for SVC systems and understand SVC systems through simulation.