• The Transactions of the Korean Institute of Electrical Engineers A
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• v.49 no.10
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• pp.479-485
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• 2000

This paper presents a analysis method for dynamic characteristics of power system using a Genetic-based Power System Stabilizer(PSS). The proposed PSS parameters are optimized using Genetic Algorithm(GA) in order to maintain optimal operation of generator under the various operating conditions. To decrease the computational time, real variable string is adopted. The results tested on a single machined infinite bus system verify that the proposed controller has better dynamic performance than conventional controller.

• Journal of Power Electronics
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• v.11 no.5
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• pp.734-742
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• 2011

In this paper a robust method is presented for the combined design of STATCOM and Power System Stabilizer (PSS) controllers in order to enhance the damping of the low frequency oscillations in power systems. The combined design problems among PSS and STATCOM internal ac and dc voltage controllers has been taken into consideration. The equations that describe the proposed system have been linearized and a Fuzzy Logic Controller (FLC) has been designed for the PSS. Then, the Particle Swarm Optimization technique (PSO) which has a strong ability to find the most optimistic results is employed to search for the optimal STATCOM controller parameters. The proposed controllers are evaluated on a single machine infinite bus power system with the STATCOM installed in the midpoint of the transmission line. The results analysis reveals that the combined design has an excellent capability in damping a power system's low frequency oscillations, and that it greatly enhances the dynamic stability of power systems. Moreover, a system performance analysis under different operating conditions and some performance indices studies show the effectiveness of the combined design.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.54 no.9
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• pp.434-440
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• 2005

This paper describes an optimized Scheme of reactive-power compensation for the low short-circuit-ratio AC system interconnected with the HVDC system. An HVDC system interconnected with tile low SCR AC system is vulnerable to the ac voltage variation, which brings about the commutation failure of the converter. This problem can be solved using optimized compensation of reactive power. In this study, a benchmark system for HVDC system interconnected with low SCR AC system is derived using PSS/E simulation. Then an optimized srheme for reactive power compensation was derived using integer programming. The feasibility of proposed scheme was analyzed through silnulations with PSS/E and PSCAD/EMTDC. The proposed scheme can compensate the reactive power accurately and minimize the number of switching for harmonic filters and shunt reactors.

• Fashion & Textile Research Journal
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• v.22 no.2
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• pp.233-239
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• 2020

We proposed a simple process of fabricating electroconductive textiles by coating conductive polymer PEDOT:PSS (Poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate)) on biocompatible PLA (Poly Lactic Acid) nanofiber web for application to smart healthcare. Electroconductive textiles were obtained by a drop-coating process using different amounts of PEDOT:PSS solutions., DMSO (dimethyl sulfoxide) was then used as an additive in the post-treatment process to improve conductivity. The surface morphology of the specimens was observed by FE-SEM. The chemical structures of the specimens were characterized using FTIR. The electrical properties (linear and sheet resistance) of the specimens were measured. The effect of the bending angles on the electrical properties was also investigated to confirm their applicability as wearable smart textiles. FE-SEM and FTIR analysis confirmed that the deposition of PEDOT:PSS on the PLA nanofiber web surface was successful. The conductivity of the PEDOT:PSS/PLA nanofiber web was enhanced up to 1.5 ml with an increasing amount of PEDOT:PSS solutions, but there was no significant difference at 2.0 ml. The optimum condition of PEDOT:PSS deposition was established to 1.5 ml. Even when the specimen coated with 1.5 ml was bent every 30°, the change in the electrical resistance values was still low within 3.7 Ω. It confirmed that stable electrical performance was maintained and proved the applicability as a flexible textile sensor.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.52 no.5
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• pp.241-249
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• 2003

This paper describes a novel approach for performing eigenvalue analysis and frequency domain analysis of multi-machine power system. The salient feature of this approach is a direct approach for constructing the state matrix equations of linearized power systems about its operating point using modular technique. These state matrix equations are then used to obtain eigenvalues and mode shapes of the system, and frequency response, or Bode, plots of selected transfer functions. The proposed program provides a flexible tool for systematic analyses of tuning PSS's parameters. The paper also presents its application to the analyses of a single-machine infinite bus system and two-area system with 4 machines.

• Proceedings of the KIEE Conference
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• 1999.07c
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• pp.1321-1323
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• 1999

In this paper, a robust $H_{\infty}$ optimal design problem under 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. It is shown that the proposed $H_{\infty}$ PSS tuned using genetic algorithm is more robust than conventional PSS.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.51 no.2
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• pp.83-92
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• 2002

In this paper, we design a GA-fuzzy precompensator for enhancement of power system stability. Here, a fuzzy prerompensator is designed as a fuzzy logic-based precompensation approach for Power System Stabilizer(PSS). This scheme is easily implemented simply by adding a fuzzy precompensator to an existing 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 function 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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• 2003.07a
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• pp.227-229
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• 2003

In this paper, we design a Power System Stabilizer for a Thyristor Controlled Series Capacitor(TCSC-PSS) for enhancement of power system stability. Here, PSS parameters are optimized using Genetic Algorithm(GA) in order to maintain optimal operation of TCSC. 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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• 1996.07b
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• pp.652-654
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• 1996

A study of the coordinated control of a TCSC and an existing PSS is presented when both are used to damp the low frequency oscillations. TCSC is modeled by the first order delay model. Linear quadratic Gaussian controller is used for designing PSS and TCSC supplementary controller. The performance of the proposed controllers is simulated in a one machine infinite bus model. As a result, it is shown that to damp the low frequency oscillations efficiently, it is necessary to control TCSC and PSS simultaneously.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.12
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• pp.2183-2189
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• 2011

Since main portion of the required electric power in Jeju Island is provided from the mainland through two HVDC lines, Jeju HVDC has a most significant impact on Jeju power system. Average wind speed of Jeju Island is the highest among several candidates in South Korea. So, Jeju Island has been a suitable site for the construction of wind farms where several wind farms are now operating and several others to be sited. Since the large-scale wind generation could have adverse impacts on the stable operation of Jeju power system, wind power is also important for the stability of Jeju power system. Therefore, accurate modeling of Jeju HVDC and wind farms is required for stability analysis of Jeju power system. In this paper, PSS/E-based dynamic modeling of Jeju HVDC and DFIG wind farms is proposed. Model-writing technique of PSS/E is used to develop USRAUX model and USRMDL model for controlling the frequency of HVDC and imposing an operation limit of wind power, respectively. Dynamic characteristics of Jeju HVDC and DFIG wind farms are analyzed through the dynamic simulations. The simulation results show the effectiveness of the developed models for Jeju power system.