scholarly journals Optimal robust stabilizer design based on UPFC for interconnected power systems considering time delay

2017 ◽  
Vol 66 (3) ◽  
pp. 459-474
Author(s):  
Hamid Reza Koofigar ◽  
Ghader Isazadeh

AbstractA robust auxiliary wide area damping controller is proposed for a unified power flow controller (UPFC). The mixedH2/H∞problem with regional pole placement, resolved by linear matrix inequality (LMI), is applied for controller design. Based on modal analysis, the optimal wide area input signals for the controller are selected. The time delay of input signals, due to electrical distance from the UPFC location is taken into account in the design procedure. The proposed controller is applied to a multi-machine interconnected power system from the IRAN power grid. It is shown that the both transient and dynamic stability are significantly improved despite different disturbances and loading conditions.

Energies ◽  
2019 ◽  
Vol 12 (2) ◽  
pp. 322 ◽  
Author(s):  
Ping He ◽  
Seyed Arefifar ◽  
Congshan Li ◽  
Fushuan Wen ◽  
Yuqi Ji ◽  
...  

The well-developed unified power flow controller (UPFC) has demonstrated its capability in providing voltage support and improving power system stability. The objective of this paper is to demonstrate the capability of the UPFC in mitigating oscillations in a wind farm integrated power system by employing eigenvalue analysis and dynamic time-domain simulation approaches. For this purpose, a power oscillation damping controller (PODC) of the UPFC is designed for damping oscillations caused by disturbances in a given interconnected power system, including the change in tie-line power, the changes of wind power outputs, and others. Simulations are carried out for two sample power systems, i.e., a four-machine system and an eight-machine system, for demonstration. Numerous eigenvalue analysis and dynamic time-domain simulation results confirm that the UPFC equipped with the designed PODC can effectively suppress oscillations of power systems under various disturbance scenarios.


2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Yunning Zhang ◽  
Dong Yue ◽  
Songlin Hu

An event-triggered scheme is adopted and applied to the design of a centralized wide-areaH∞damping controller (WAHDC) of interconnected power systems with external disturbance. Firstly, based on the linearized multimachine system model, the centralized WAHDC with event-triggered scheme design problem is described as time-delay feedback control problem. Then by using Lyapunov functional method and Jensen inequality technique, criteria for stability with anH∞norm bound and for design of the feedback controller are derived. The linear matrix inequality (LMI) is employed to solve the feedback gain. Finally, case studies are carried out based on two-area four-machine power system. Simulations indicate that the proposed WAHDC with event-triggered scheme can damp the interarea oscillation effectively when the external disturbance is bounded and significantly reduce the number of measured states released to WAHDC. Relationships between event trigger parameterσand dynamic performance,σand network utilization,σand time delay, andσand disturbance rejection level are investigated and results obtained can be used to choose an appropriate event trigger parameter.


2011 ◽  
Vol 317-319 ◽  
pp. 2204-2207
Author(s):  
Dong Mei Yang ◽  
Qing Sun

This paper is concerned with the non-fragile decentralized controller design problem for uncertain singular large-scale system with time-delay. Sufficient condition for the controller is expressed in terms of linear matrix inequalities(LMIs). When this condition is feasible, the desired controller can be obtained with additive gain perturbations and multiplicative gain perturbations. Finally, a numerical example is also given to illustrate the effectiveness.


Energies ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 824 ◽  
Author(s):  
Jinlian Liu ◽  
Zheng Xu ◽  
Liang Xiao

This paper aims to discover the general steady-state operation characteristics, as well as improving the dynamic performance, of the modular multilevel converter (MMC)-based unified power flow controller (UPFC). To achieve this, first, we established a detailed power flow model for MMC-based UPFC containing each critical part and made qualitative and graphical analyses combining 2-dimensional operation planes and 3-dimensional spatial curve surfaces comprehensively to derive general power flow principles and offer necessary references for regulating UPFC. Furthermore, to achieve better performance, we designed a feedforward control strategy for the shunt and series converters of UPFC, both comprising two feedforward control blocks with the introduction of necessary compensating branches, and analyzed the performance in complex and time domain, respectively. The proposed power flow principles and control strategies were validated by a (power systems computer aided design) PSCAD model of 220 kV double-end system; the results reveal the MMC-based UPFC can realize the power flow principles and improve the control speed, stability, and precision of the power flow regulations under various conditions.


Symmetry ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 375
Author(s):  
Hejun Yao

The problem of anti-saturation control for a class of time-delay systems with actuator saturation is considered in this paper. By introducing appropriate variable substitution, a new delay time-delay systems model with actuator saturation systems is established. Based on the Lyapunov stability theory, the stability condition and the anti-saturation controller design method are obtained by using the linear matrix inequality approach. By introducing the matrix into the Lyapunov function, the proposed conditions are less conservative than the previous results. Finally, a simulation example shows the validity and rationality of the method.


Author(s):  
Abu H.M.A. Rahim ◽  
Jamil M Bakhashwain ◽  
Samir A Al-Baiyat

This article investigates the various damping controls of the unified power flow controller (UPFC). A detailed dynamic model of the UPFC including the possible damping control parameters has been derived. A method of determining the stable operating states of the nonlinear system model has been presented. Fixed parameter robust controllers for the identified controls have been designed satisfying the robustness conditions on performance and stability. The robust controller design has been carried out with the aid of a simple graphical 'loop-shaping' construction procedure. Simulation studies show that both robust series converter voltage magnitude and shunt converter phase angle provide extremely good damping. Combined application of the above two controls, however, gives the best damping profile over a wide range of operation. PI controllers having optimized gain settings were employed to evaluate the robustness of the proposed controllers.


2011 ◽  
Vol 18 (9) ◽  
pp. 1375-1379 ◽  
Author(s):  
Hua Wang ◽  
Xian-Hai Shen ◽  
Liang-Xu Zhang ◽  
Xiao-Jin Zhu

Based on the linear matrix inequality, a linear feedback control is presented to realize active vibration suppression of a class of flexible structure. By introducing an appropriate modal transformation, the controller design procedure can be simplified greatly. A specific Lyapunov function is adopted to induce the asymptotical stability of the flexible structure. Simulation results for flexible spacecraft are provided to illustrate the effectiveness of the proposed scheme.


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