• 대한전기학회논문지:전력기술부문A
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• 제49권3호
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• pp.85-94
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• 2000

In this paper, a robust H$\infty$ optimal tuning problem of a structure-specified PSS is investigated for power systems with parameter variation and disturbance uncertainties. Genetic algorithm is employed for optimization method of PSS parameters. The objective function of the optimization problem is the H$\infty$-norm of a closed loop system. The constraint of the optimization problem are based on the stability of the controller, limits on the values of the parameters and the desired damping of the dominant oscillation mode. It is shown that the proposed H$\infty$ PSS tuned using genetic algorithm is more robust than conventional PSS.

• 조명전기설비학회논문지
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• 제15권3호
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• pp.57-66
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• 2001

본 논문에서는 전력계통의 안정도를 향상시키기 위하여 동기 발전기와 정지형 무효전력 보상기예 대한 퍼지-PI 제어기를 설계하기 위한 제어 기법을 설명하였다. 정지형 무효전력 보상기는 고정된 용량의 커패시터와 싸이리스터 제어에 의하여 용량이 가변되는 인덕터가 병렬로 연결된 구조를 가지고 있으며, 시스템 전압을 제어할 뿐만 아니라 동기 발전기의 제동을 개선하기 위해 설계되었다. 본 논문에서 제안한 SVC 계통의 퍼지-PI 제어기의 파라미터는 퍼지 추론 기법에 의해 자동 동조되어진다. 퍼지 추론 기법은 일반적인 기법과는 달리 인간의 경험과 전문가의 지식을 제어 규칙으로 제어 동작을 결정하였다. 그리하여 인간의 추론 과정과 매우 유사한 MMGM을 이용하여 PI 이득의 퍼지 추론 기법을 SVC 계통에 적용하여 설명하였다. 제안된 방법의 강인성을 입증하기 위해 중부하시, 정상부하시 및 경부하시에 초기 전력을 변동시킨 경우에 대하여 시스템의 회전자각, 각속도 편차 특성 및 단자전압의 동특성을 고찰하여 기존의 전력시스템안정화장치보다 응답특성이 우수함을 보였다.

• 대한전기학회논문지:전력기술부문A
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• 제49권7호
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• pp.350-358
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• 2000

Based on the results in the first-part paper, PSS tuning methods including the determination of PSS gain and compensation of phasor lagging are investigated in this second part. In the phase compensation, PSS should compensate phase lagging, resulted from power system-generator-excitation system loop, to provide damping torque in equal phase with the generator speed. Also, PSS gain should be determined to provide maximum damping torque as much as possible without the other modes unstable. In this paper, gain tuning method using the root-locus and the phase compensation of PSS at the one machine with infinite bus system are presented. The differences between PSS tuning at the tuning condition and at the least-stable condition are also discussed.

• 대한전기학회논문지:시스템및제어부문D
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• 제49권4호
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• pp.165-174
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• 2000

This paper presents the application of H$\infty$ control synthesis using LMI optimization method to power system stabilizer(PSS) design. Since power system is usually operated under circumstance of unmeasurable uncertainties and external disturbances, the improvement of small signal stability becomes one of the most important issue for securing system stability and preventing low frequency oscillation phenomena. The LMI optimized H$\infty$ PSS provides robust performance and guarantees the internal stability under these operating conditions. The global optimal H$\infty$ norm is found using LMI convex optimization method which is more systematic than standard two Riccati solution method. The design results are simulated for a case study. We verified that the LMI method shows the best performance characteristic smong standard Riccati method and conventional lead/lag method.

• 대한전기학회논문지:전력기술부문A
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• 제49권9호
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• pp.433-445
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• 2000

In this paper, optimal tuning problem of power system stabilizer(PSS) using Immune Algorithm(IA) is investigated to improve power system dynamic stability. In proposed method, objective function is represented as antigens. An affinity calculation is embedded within the algorithm for determining the promotion or suppression of antibody. An antibody that most fits the antigen is considered as the solution to PSS tuning problem. The computaton performance by the proposed method is compared with Genetic Algorithm(GA). The porposed PSS using IA has been applied for two sample system, single-machine infinite bus system and multi-machine power system. The performance of the proposed PSS is compared with that of conventional PSS. It is shown that the proposed PSS tuned using immune algorithm is more robust than conventional PSS.

• 대한전기학회논문지:전력기술부문A
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• 제48권6호
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• pp.704-711
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• 1999

This paper presents a design of fuzzy power system stabilizer (FPSS) using adaptive evolutionary computation (AEC). We have proposed an adaptive evolutionary algorithm which uses a genetic algorithm (GA) and an evolution strategy (ES) in an adaptive manner in order to take merits of two different evolutionary computations. FPSS shows better control performances than conventional power system stabilizer (CPSS) in three-phase fault with heavy load which is used when tuning FPSS. To show the robustness of the proposed FPSS, it is appliedto damp the low frequency oscillations caused by disturbances such as three-phase fault with normal and light load, the angle deviation of generator with normal and light load and the angle deviation of generator with heavy load. Proposed FPSS shows better robustness than CPSS.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 D
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• pp.2188-2190
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• 2004

This paper presents an implementation of power system stabilizer using inverse dynamic neuro controller. Traditionally, mutilayer neural network is used for a universal approximator and applied to a system as a neuro-controller. In this case, at least two neural networks are used and continuous tuning of neuro-controller is required. Moreover, training of neural network is required considering all possible disturbances, which is impractical in real situation. In this paper, Taylor Model Based Inverse Dynamic Neuro Model (TMBIDNM) is introduced to avoid this problem. Inverse Dynamic Neuro Controller (IDNC) consists of TMBIDNM and Error Reduction Neuro Model (ERNM). Once the TMBIDNM is trained, it does not require retuning for cases with other types of disturbances. The controller is tested for one machine and infinite-bus power system for various operating conditions.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 추계학술대회 논문집 학회본부
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• pp.206-208
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• 1997

This paper presents a design of self_tuning fuzzy logic controller using Genetic Algorithms for power system stabilization. FPSS(Fuzzy Logic Power System Stabilized is applied to the KERI(Korea Electric Research Int.) power system simulator so that its efficiency can be investigated in real time control. Genetic Algorithms are used to determine fuzzy membership functions. Experiment results show the better performances with FPSS in comparison to no PSS.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 A
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• pp.149-151
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• 2001

This paper proposes the design of STATCOM(static synchronous compensator) stabilizer for improving power system stability using fuzzy logic controller(FLC). The STATCOM DC voltage regulator contributes negative damping to the power system as the installation of STATCOM DC voltage regulator. STATCOM stabiliser is superimposed on the AC voltage regulator to compensate the negative damping effect. To evaluate usefulness of the proposed method, we perform the nonlinear simulation on a single-machine infinite bus system. As results of the simulations, the proposed method shows better control performance than PI controller in terms of damping effects.

• 대한전기학회논문지
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• 제35권8호
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• pp.353-362
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• 1986

This paper shows that 6 pulse converter instead of 12 pulse converter can be used for the control of Superconducting Magnet Energy Storage(SMES) to improve the stability and to suppress the voltage fluctuation of power system. In order to prevent the commutation failure, when 6 pulse converter used for simultaneous control of real power and reactive power is asymmetrically controlled, stable control region has been presented by analyzing the commutation phenomena at critical points which distinguish the stable control region from the unstrol control region. Harmonic components of line current and output voltage have been calculated. Finally, computer simulation of power system stabilization has been presented to show the effectiveness of the proposed method. According to the computation results, SMES controlled by the 6 pulse converter is an effective measure in reducing the oscillation and the transient instability of the power system.