• Proceedings of the KIEE Conference
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• summer
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• pp.292-294
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• 2004

In this paper, we design the GA-fuzzy precompensator of a Power System Stabilizer for Thyristor Controlled Series Capacitor(TCSC-PSS) for enhancement of power system stability. Here a fuzzy precompensator is designed as a fuzzy logic-based precompensation approach for TCSC-PSS. This scheme is easily implemented simply by adding a fuzzy precompensator to an existing TCSC-PSS. And we optimize the fuzzy precompensator with a genetic algorithm for complements the demerit such as the difficulty of the component selection of fuzzy controller, namely, scaling factor, membership Auction and control rules. Simulation results show that the proposed control technique is superior to a conventional PSS in dynamic responses over the wide range of operating conditions and is convinced robustness and reliableness in view of structure.

• Proceedings of the KIEE Conference
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• 2001.05a
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• pp.262-265
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• 2001

최근 전력계통의 과부하, 전압안정도 등의 문제에 대한 해결책으로 FACTS (Flexible AC Transmission Systems)가 대두되고 있다. FACTS 설비에는 TCSC (Thyristor-Controlled Series Capacitor), SSSC (Static Synchronous Series Capacitor)와 같은 직렬 기기와 SVC(Static Var Compensator), STATCOM(STATic COMpensator) 와 같은 병렬기기 그리고, 본 논문에서 다루는 UPFC와 같은 직 병렬기기로 나누어진다. UPFC는 SSSC와 STATCOM을 결합한 형태로 유 무효전력을 동시에 보상할 수 있는 FACTS 기기이다. 본 논문에서는 한전 계통의 전압안정도 향상과 과부하 해소를 위해 강진S/S에 설치예정인 80MVA UPFC의 하드웨어 특성과 주변계통의 특성을 소개하고, UPFC와 한전 계통의 연계방안과 시험방안을 설명한다.

• Proceedings of the KIEE Conference
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• 2000.07a
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• pp.37-39
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• 2000

This paper describes the application of Fuzzy Logic Controller (FLC) to Thyristor Controlled Series Capacitor (TCSC) which can have significant impact on Power system dynamics. The function of the FLC is to control the firing angle of the TCSC. We tuned the scaling factors of the FLC using Tabu Search. The proposed FLC is used for damping the low frequency oscillations caused by disturbances such as the sudden changes of small of large loads or the outages in the generators or transmission lines. To evaluate usefulness of the proposed FLC. we performed the computer simulation for single-machine infinite system. The response of FLC is compared with that of PD controller optimized using Tabu Search. Simulation results that the FLC shows the better control performance than PD controller.

• Transactions on Electrical and Electronic Materials
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• v.17 no.6
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• pp.341-350
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• 2016

The current study is dedicated to design a novel coordinated controller to effectively increase power system rotor angle stability. In doing so, the coordinated design of an AVR (automatic voltage regulator), PSS2B, and TCSC (thyristor controlled series capacitor)-based POD (power oscillation damping) controller is proposed. Although the recently employed coordination between a CPSS (conventional power system stabilizer) and a TCSC-based POD controller has been shown to improve power system damping characteristics, neglecting the negative impact of existing high-gain AVR on the damping torque by considering its parameters as given values, may reduce the effectiveness of a CPSS-POD controller. Thus, using a technologically viable stabilizer such as PSS2B rather than the CPSS in a coordinated scheme with an AVR and POD controller can constitute a well-established design with a structure that as a high potential to significantly improve the rotor angle stability. The design procedure is formulated as an optimization problem in which the ITSE (integral of time multiplied squared error) performance index as an objective function is minimized by employing an IPSO (improved particle swarm optimization) algorithm to tune adjustable parameters. The robustness of the coordinated designs is guaranteed by concurrently considering some operating conditions in the optimization process. To evaluate the performance of the proposed controllers, eigenvalue analysis and time domain simulations were performed for different operating points and perturbations simulated on 2A4M (two-area four-machine) power systems in MATLAB/Simulink. The results reveal that surpassing improvement in damping of oscillations is achieved in comparison with the CPSS-TCSC coordination.

• Journal of Electrical Engineering and Technology
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• v.8 no.2
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• pp.252-261
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• 2013

In this paper, a nonlinear adaptive damping controller based on radial basis function neural network (RBFNN), which can infinitely approximate to nonlinear system, is proposed for thyristor controlled series capacitor (TCSC). The proposed TCSC adaptive damping controller can not only have the characteristics of the conventional PID, but adjust the parameters of PID controller online using identified Jacobian information from RBFNN. Hence, it has strong adaptability to the variation of the system operating condition. The effectiveness of the proposed controller is tested on a two-machine five-bus power system and a four-machine two-area power system under different operating conditions in comparison with the lead-lag damping controller tuned by evolutionary algorithm (EA). Simulation results show that the proposed damping controller achieves good robust performance for damping the low frequency oscillations under different operating conditions and is superior to the lead-lag damping controller tuned by EA.

• Journal of Electrical Engineering and Technology
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• v.5 no.2
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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.