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This paper mainly study on the coordinated voltage control scheme with model predictive control (MPC). As the decomposition-coordination technology and the auxiliary problem principle is employed into the MPC based voltage control problem, a distributed voltage control model and structure can be obtained, and the global centralized optimization problem is decomposed into some sub-problems. All sub-problems...
Dynamic voltage stability analysis is mainly based on the time-domain solution of power system differential and algebraic equations. The modeling of each power element has a great influence on the correctness and complexity of stability analyzing. It is significant to model appropriately for simplifying calculation and drawing out principal contradiction. In this paper, the dynamical mechanism of...
In this thesis, existing instability criterion and its stability indicator τ for autonomous single machine infinite-bus system (SMIB) are firstly given, which reflect convex-concave characteristics of the trajectory inΔω-δ phase-plane. On this basis, it is discussed that there are some problems when the instability criterion of autonomous SMIB system is used in non-autonomous SMIB system. Proceeding...
Dynamic voltage stability analysis is mainly based on the time-domain solution of power system differential equations. The modeling of each power element has a great influence on the correctness and complexity of stability analyzing. It is a significant work to model appropriately for simplifying calculation and drawing out principal contradiction. Firstly, the dynamical mechanism of voltage stability...
Voltage stability is one of the aspects of the power system stability. Since regulating transformers are more and more used in modern power system, tap change has often been considered as a principal mechanism that may lead to voltage collapse, but tap change can also rescue a would-be collapse system by extending the power transfer limit. Using time domain medium-and-long term voltage stability simulation...
To improve the stability of the power system integrated of wind farm, the wind power system energy function is proposed in this paper based on the energy conservation law. Then a stability control strategy based on the energy function is introduced. The impacts of DFIG operation limits on the control effect are also discussed. By variable speed operation, the control strategy restrains the wind power...
This paper presents a new scheme for power line autoreclosure technology, the integrated adaptive optimal reclosure. The background of the development is firstly outlined and the basic principles of these new techniques are described. These include the adaptive reclosure and the optimal reclosure techniques. The new scheme proposed is based on the latest development in digital substation, in which...
Appropriate modeling of dynamic loads is of primary importance in voltage stability studies, especially increasing use of induction machines in both consumption and generation. This paper is mainly related to short-term voltage instability depending on time domain simulation. The actuality of voltage instability research is summarized, and the mechanisms of short- term voltage stability are explained...
Self-adaptive system islanding refers to the separation of an interconnected power system into electrically isolated islands automatically based on the identification of unstable mode. A fast searching algorithm for self-adaptive power system islanding, which is called multilevel reduced graph partitioning (MLRGP) algorithm, is presented in this paper. The aim of this algorithm is that the generation...
Based on the transient energy function (TEF) theory with classical models considered, the optimal re-closing time (ORT) can be calculated accurately. This paper mainly focuses attention on the validity and practicability analyzing of ORT obtained from this method. Firstly, the characteristics and influencing factors of the ORT are put forward and analyzed, and also the setting strategy of re-closing...
In this paper, a method is proposed for fast and accurate online detection of transient instability based on real-time measurement. The cluster of critical machines is determined and refreshed at each time. Determination of the irrevocable loss of synchronism is made based on the geometric characteristic of critical machines trajectory. Unlike the previous extended equal-area criterion method, it...
The re-closing time of a transmission line has a distinct influence on power system transient stability. There is an optimal re-closing time (ORT) for all transmission line faults, no matter the instantaneous fault or permanent one. Based on the transient energy function (TEF) theory with classical models considered, the ORT can be calculated accurately. This paper mainly focuses attention on the...
In this paper, a method, which is essential in initiating emergency control measures, is proposed for fast and accurate online detection of transient instability based on real-time measurement. Under a certain disturbance, the candidate critical cluster of power system is predicted and refreshed at each sampling step. The method identifies the loss of synchronism at each time step by observing the...
Centralized control using the wide-area information has been suggested to enhance the dynamic performance of large interconnected power systems. According to the inverse system method and LQR optimal control theory, this paper presents a nonlinear hierarchical global controller based on the wide-area information including the on-line measured center of rotor angle and total unbalanced power. Moreover,...
The study of various stability-control methods for a transmission system indicates that the reclosing time of a transmission line has a distinct influence on system stability. And there is an optimal reclosing time (ORT) for all transmission line faults. Utilizing the transient energy function (TEF) with classical models considered, the ORT setting computation method is proposed. This paper shows...
Autoreclosure schemes have been widely used in power system and an effective way to improve greatly the dependability and stability of power systems. However, most of these schemes adopt a presetting time to reclose breaker after a tripping operation. There are many problems due to the conventional reclosure schemes. In this paper, a self-adaptive auto-reclosure criterion using dual-window transient...
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