• Advances in Energy Research
• /
• 제4권4호
• /
• pp.255-274
• /
• 2016

This paper presents a novel symbiotic organisms search (SOS) algorithm to optimize both real power loss (RPL) and voltage stability limit (VSL) of a transmission network by controlling the variables such as unified power flow controller (UPFC) location, UPFC series injected voltage magnitude and phase angle and transformer taps simultaneously. Mathematically, this issue can be formulated as nonlinear equality and inequality constrained multi objective, multi variable optimization problem with a fitness function integrating both RPL and VSL. The symbiotic organisms search (SOS) algorithm is a nature inspired optimization method based on the biological interactions between the organisms in ecosystem. The advantage of SOS algorithm is that it requires a few control parameters compared to other meta-heuristic algorithms. The proposed SOS algorithm is applied for solving optimum control variables for both single objective and multi-objective optimization problems and tested on New England 39 bus test system. In the single objective optimization problem only RPL minimization is considered. The simulation results of the proposed algorithm have been compared with the results of the algorithms like interior point successive linear programming (IPSLP) and bacteria foraging algorithm (BFA) reported in the literature. The comparison results confirm the efficacy and superiority of the proposed method in optimizing both single and multi objective problems.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2014년도 추계학술대회 논문집
• /
• pp.137-138
• /
• 2014

우리나라 전력계통은 점점 복잡화, 대형화되어 가고 있으나, 이에 따른 전력설비의 신설은 날로 어려워지고 있다. 이러한 변화에 능동적으로 대처하기 위해 FACTS(Flexible AC Transmission System) 기술이 주목받고 있으며, FACTS는 대용량 전력전자기술을 이용하여 송전선로의 안정도 제어 및 송전용량 증대를 목적으로 설치된다. 현재 우리나라 전력계통에는 SVC, UPFC, STATCOM 등의 기기들이 개발되어 운영되어 있으며, 그 중에 SVC가 대표적으로 변전소에 많이 설치되어 무효전력 보상으로 전압안정도를 향상시키고 있다. 이에 따라서 본 논문은 154kV 송전계통에서 SVC의 여러 제어 방법 중 Susceptance 제어에 관해서 기술하고자 한다.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2000년도 추계학술대회 논문집 학회본부 A
• /
• pp.33-35
• /
• 2000

We propose a intelligent controller for FACTS(Flexible AC Transmission System) device to stabilize a power system. In order to identify the nonlinear characteristics of the power system and to estimate a control signal, an artificial neural network is utilized. The control signal which is provided for FACTS device installed in the network is produced. The proposed controller is applied to Unified Power Flow Controller(UPFC) to verified the effectiveness of the proposed control system. The results show that the proposed nonlinear FACTS controller is able to enhance the transient stability of three machine nine bus power system.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2003년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
• /
• pp.220-223
• /
• 2003

본 논문에서는 한국전기연구원에서 보유하고 있는 아날로그형 전력계통 시뮬레이터인 KERI 시뮬레이터에 적용하고자 개발 중인 TCSC 시스템 시뮬레이터의 설계 방법과 적용 결과를 제시하고 한다. KERI 시뮬레이터는 전력계통시스템을 모의하기위해 한국전기연구원에서 보유하고 있는 실험장비로 3개의 동기발전기와 345kV 송전선로 모델, 각종 계통 설비의 축소 모형으로 구성되어 있다. 지금까지 UPFC, STATCOM과 같은 FACTS 모의장치의 계통 적용을 검토하기 위한 연구가 이루어져 왔다.

• 전기학회논문지
• /
• 제59권6호
• /
• pp.1011-1016
• /
• 2010

It is an important issue to electric power system operations that it can reliably supply large-capacity power to consumption area as due to increasing power demand growth. For this purpose, The FACTS equipment based on Power IT technology with the existing mechanical compensators has been applied to power system. Therefore we suggest on this paper that a plan for coordination control of multiple power compensation equipment in order to increase the utilization of each facility and secure operation margin capacity. As the result of simulation, it is possible to cope actively with a suddenly changed power system. This helps greatly for the voltage stability and supply reliability in a suddenly changed power system.

• 전기학회논문지
• /
• 제60권5호
• /
• pp.971-976
• /
• 2011

This paper proposes a test system for a valve and poles building blocks used for large scale inverters such as STATCOM, SSSC, UPFC and VSC HVDC. Power semiconductors in the valve are normally connected in series to withstand switching voltage much larger than the voltage rating of a single power semiconductor. Therefore, there is a need to verify if the dynamic voltage sharing during switching in a valve is satisfactory. In this paper, we propose a test system that provides the necessary test condition: voltage and current in the valve using resonant circuits. A test scheme for a single phase inverter consisting two poles is also proposed. The performance of the inverter pole has to be verified at the factory test, before the system is installed at the site to secure the reliability of the system. The proposed scheme makes it possible to confirm if the pole can withstand voltage and current switching condition and handle loss.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2000년도 하계학술대회 논문집 A
• /
• pp.22-24
• /
• 2000

As a competition is introduced in the electricity supply industry, a congestion problem arises in the transmission network. The congestion causes the transmission cost to increase. One way to decrease the congestion cost is to control the transmission flow through the installation of FACTS(Flexible AC Transmission system). This paper deals with the optimal site of the FACTS for reducing the congestion cost using a shadow price which is one of the economic signals for the systems. Test results show that the site of the FACTS(UPFC) is optimal to minimize the congestion cost by the proposed algorithm.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1998년도 추계학술대회 논문집 학회본부 C
• /
• pp.1033-1036
• /
• 1998

In this research project, two aspects of small signal stability are studied: improvement in Hessenberg method to compute the dominant electromechanical oscillation modes and siting FACTS devices to damp the low frequency oscillation. Fourier transform of transient stability simulation results identifies the frequencies of the dominant oscillation modes accurately. Inverse transformation of the state matrix with complex shift equal to the angular speed determined by Fourier transform enhances the ability of Hessenberg method to compute the dominant modes with good selectivity and small size of Hessenberg matrix. Any specified convergence tolerance is achieved using the iterative scheme of Hessenberg method. Siting FACTS devices such as SVC, STACOM, TCSC, TCPR and UPFC has been studied using the eigen-sensitivity theory of augmented matrix. Application results of the improved Hessenberg method and eigen-sensitivity to New England 10-machine 39-bus and KEPCO systems are presented.

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

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
• /
• 제48권11호
• /
• pp.655-662
• /
• 1999

This paper describes controller design and simulation-model development of a dynamic voltage compensator using series and shunt inverters. The control system was designed using PI controller and vector relationship between the supply voltage and load voltage. A simulation model with EMTP was developed to analyze performance of the controller and the whole system. The simulation and experiment results confirm that the dynamic compensator can restore the load voltage under the fault of the distribution system, such as single-line-ground fault, three-line-to-ground fault, and line-to-line fault.