• KIEE International Transactions on Power Engineering
• /
• 제5A권4호
• /
• pp.378-384
• /
• 2005

This paper proposes a new series and parallel Sin+Cos PSS (power system stabilizer) for the purpose of improving the existing PSS1A's performance. The purpose of the PSS is to enhance the damping of power system oscillations through injection of auxiliary signals for an excitation control terminal. The proposed series and parallel Sin+Cos PSS is connected adding the Sin+Cos terms additionally with the serial and parallel connection in a conventional PSS1A. The proposed controller is aimed at considering the damping of oscillation when it changes parameter fluctuations or operational load variations in a power system. The electric power system used is the KEPCO system and the voltage of the power transmission line is 154kV and 345kV. The PSCAD/EMTDC package is used to authorize the effect of the proposed controller. Simulations were shown by and compared with the waveforms for frequency, voltage and electric power.

• 조명전기설비학회논문지
• /
• 제23권12호
• /
• pp.191-200
• /
• 2009

본 논문에서는 전력계통에서 발생하는 저주파 진동을 억제하여 계통에 댐핑력을 제공함으로써 계통 안정도를 향상시킬 수 있는 전력계통 안정화장치의 정수선정 기법과 현장시험을 통한 성능검증 방법을 제시하였다. 대상 발전기는 우리나라 계통에 설치되어 있는 612[MVA]급 화력발전기이며, 축 속도를 입력으로 하는 아날로그 전력계통 안정화장치를 적용대상으로 하였다. 본 논문에서는 먼저, 오프라인에서 선형 해석 및 고유치 해석을 통하여 최적정수를 선정하는 기법을 제시하고, 시간영역 과도 안정도 해석을 이용하여 선정된 정수를 검증하였다(Part I). 또한, 선정된 전력계통 안정화장치의 성능을 온라인 현장시험을 통하여 최종적으로 검증하였으며, 정수선정 전 후의 오프라인 시뮬레이션 결과와 온라인 시험결과를 비교 분석함으로써, 결정된 모델의 적정성을 확인하였다(Part II). 이를 통하여, 축 속도를 입력으로 하는 PSS의 정수선정 방법과 실 계통 현장시험을 통한 성능검증 방법을 제시하였다.

• 대한전기학회논문지
• /
• 제38권5호
• /
• pp.337-342
• /
• 1989

Since the late 1960s, the selection of the parameters of power system stabilizer (PSS) to damp out sustained low frequency oscillation of power generators in the steady state has been an active research area. This paper presents a new approach to select the optimal PSS parameters using the sensitivity of the quadratic performance with respect to the PSS parameters. The proposed algorithm has been applied to Seo-Cheon fossil power plant.

• Journal of Electrical Engineering and Technology
• /
• 제5권3호
• /
• pp.503-510
• /
• 2010

This paper proposes the use of fuzzy applications to a 4-machine and 10-bus system to check stability in open conditions. Fuzzy controllers and the excitation of a synchronous generator are added. Power system stabilizers (PSSs) are added to the excitation system to enhance damping during low frequency oscillations. A fuzzy logic power system stabilizer (PSS) for stability enhancement of a multi-machine power system is also presented. To attain stability enhancement, speed deviation ($\Delta\omega$) and acceleration ($\Delta\varpi$) of the Kota Thermal synchronous generator rotor are taken as inputs to the fuzzy logic controller. These variables have significant effects on the damping of generator shaft mechanical oscillations. The stabilizing signals are computed using fuzzy membership functions that are dependent on these variables. The performance of the fuzzy logic PSS is compared with the open power system, after which the simulations are tested under different operating conditions and changes in reference voltage. The simulation results are quite encouraging and satisfactory. Similarly, the system is tested for the different defuzzification methods, and based on the results, the centroid method elicits the best possible system response.

• Journal of Electrical Engineering and Technology
• /
• 제9권2호
• /
• pp.379-389
• /
• 2014

Low frequency oscillations (LFOs) are load angle oscillations that have a frequency between 0.1-2.0 Hz. Power system stabilizers (PSSs) are very effective controllers in improvement of the damping of LFOs. PSSs are designed by linearized models of the power system. This paper presents a new model of the power system that has the advantages of the Single Machine Infinite Bus (SMIB) system and the multi machine power system. This model is named a single machine normal-bus (SMNB). The equations that describe the proposed model have been linearized and a lead PSS has been designed. Then, particle swarm optimization technique (PSO) is employed to search for optimum PSS parameters. To analysis performance of PSS that has been designed based on the proposed model, a few tests have been implemented. The results show that designed PSS has an excellent capability in enhancing extremely the dynamic stability of power systems and also maintain coordination between PSSs.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1998년도 하계학술대회 논문집 C
• /
• pp.1143-1146
• /
• 1998

Static excitation systems with high gain and fast response times greatly aid transient stability. but at the same time tend to reduce small signal stability. The objective of the power system stabilizer(PSS) control is to provide a positive contribution to damping of the generator rotor angle swings, which are in a broad range of frequencies in the power system. Therefore, this paper shows the field test results for the GE's EX2000 PSS tuning on units at Seo-Incheon power plant. The test is to verify that the PSS response meets GE's design, criteria. The responses of generator terminal voltage, active power, field voltage and current were analyzed and PSS gain was tuned by 10 finally.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1997년도 하계학술대회 논문집 D
• /
• pp.1174-1176
• /
• 1997

In this paper, the power system stabilizer(PSS) using the sliding mode observer-model following(SMO-MF) including closed-loop feedback(CLF) for single machine system is extended to multimachine system.

• 대한전기학회논문지:전력기술부문A
• /
• 제50권1호
• /
• pp.13-19
• /
• 2001

This paper deals with decentralized control scheme and its application to multi-machine power systems. Decentralized control scheme has several practical advantages, because power system has geographically distributed characteristics. In this paper, decentralized observer-based optimal Power System Stabilizer(PSS) and Thyristor-Controlled Series Capacitor(TCST) controller are designed and tested in WSCC 9 bus system with one TCSC installed. Simulation results show that the proposed decentralized controller has satisfactory performances comparable to the centralized controller. In addition, using modal analysis, this paper shows that the proposed decentralized controller significantly affects only one pair of eigenvalues which have high participation with each generator, while slightly affects other eigenvalues. This result indicates that the application of the decentralized control scheme to enhance power system dynamic stability via excitation control have potential advantages because each low-damped mode occurs dominantly by each decentralized subsystem.

• 대한전기학회논문지
• /
• 제40권5호
• /
• pp.453-459
• /
• 1991

This paper presents a new algorithm to select optimal parameters and location of power system stabilizer (PSS). A new performance measure, which evaluates the share of a particular mode among state responses, is introduced. The gradient of the performance measure with respect to PSS parametes is derived in an explicit form, so optimal parameters of PSS can be obtained by the steepest descent method. The machine, with which it is most probable to reduce the performance measure, is identified as the optimum site for PSS application.

• 대한전기학회논문지:전력기술부문A
• /
• 제50권7호
• /
• pp.324-332
• /
• 2001

In this paper, it is suggested that the selection method of parameter of Power System Stabilizer(PSS) with robustness in low frequency oscillation for Static VAR Compensator(SVC) using a Real Variable Elitism Genetic Algorithm(RVEGA). A SVC, one of the Flexible AC Transmission System(FACTS), constructed by a fixed capacitor(FC) and a thyristor controlled reactor(TCR), is designed and implemented to improve the damping of a synchronous generator, as well as controlling the system voltage. The proposed PSS parameters are optimized using RVEGA in order to maintain optimal operation of generator under the various operating conditions. To decrease the computational time, real variable string is adopted. To verify the robustness of the proposed method, we considered the dynamic response of generator speed deviation and generator terminal voltage by applying a power fluctuation and three-phase fault at heavy load, normal load and light load. Thus, we prove the usefulness of proposed method to improve the stability of single machine-infinite bus with SVC system.