Survey paper: Static output feedback-A survey

Unit commitment is a complex problem which, until now and for real size systems, has been solved using heuristic methods only. This paper proposes a new Lagragian relaxation method, which produces ??-optimal solutions. The flexibility of the algorithm is such that numerous developments can be envisaged, such as simultaneous management of pumping units, probabilistic determination of the spinning reserve, etc.

A New Method for Unit Commitment at Electricite De France

This paper reviews the static output feedback problem in the control of linear, time-invariant (LTI) systems. It includes analytical and computational methods and presents in a unified fashion, the knowledge gained in the decades of research into this most important problem. >

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Static output feedback: a survey

Increasing interest has been seen in applying fuzzy set theory to power systems problems from the number of publications on this topic. As a relatively new research topic a need is felt to pay more attention to the understanding of the basic principles of the theory and the identification of problems suitable for solving by this method. This paper presents a survey of publications on applications of fuzzy set theory to power systems and the basic procedures for fuzzy set based methods to solve specific power systems problems. Simple numerical examples are used to show the practical procedures of problem formulation and solution. Theses examples are: generator maintenance scheduling, dynamic programming, and power system stabiliser. >

Overview and literature survey of fuzzy set theory in power systems

The thermal power plant generator maintenance scheduling problem is addressed. The problem is formulated as a mixed-integer programming problem, and it is solved by using an optimization method known as simulated annealing. Since the simulated annealing method assumes an analogy between a physical multiparticle system and a combinatorial optimization problem, a global minimum can be found with high probability through a careful annealing process. Numerical results on a real-scale test system are given, and the effectiveness of the proposed method is demonstrated. >

Maintenance scheduling by using simulated annealing method (for power plants)

Host currently used thermal-generator maintenance scheduling methods schedule each unit at a time, leading in many cases to a poor local optimum or to an unfeasible solution. Considering simultaneously all units in the scheduling process, a computationally impractical method results. In this paper a piece-wise compromising method of solution is presented, which conveniently groups generating units and uses successive approximations dynamic programming. The optimal maintenance scheduling problem is formulated by employing a suitable state-space representation; most common constraints used in practice are described and a multiple objective function is presented. The effectiveness of the optimizing method is illustrated by solving a problem with data obtained from a real system. The grouping criterion presented appears to be the cornerstone of the superior performance of the proposed method.

Generator maintenance scheduling via successive approximations dynamic programming

A number of objective criteria for optimal maintenance scheduling of thermal generators is discussed. The criteria are based on generation operating cost, reliability indices, deviations from a desired schedule and/or constraints violation penalties. A comparison of the performance of all these criteria is presented by maintenance scheduling a realistic 30 thermal-unit system. Also, the relationships between the several realibility indices are dicussed.

Several objective criteria for optimal generator preventive maintenance scheduling

Optimal output controllers for high-speed excitation systems of synchronous machines, using constant and/or dynamic feedback gains, are discussed in this paper. A general problem formulation and solution are presented. A number of combinations of measurable output variables are used for control. Also, several random characteristics of the system initial state are used in the incomplete output feedback controllers' design. Effectiveness of the stabilizers are tested subjecting the system to a small input disturbance and a three-phase-to-ground fault.

V.H. Quintana

Papers

Generator maintenance scheduling via successive approximations dynamic programming

Several objective criteria for optimal generator preventive maintenance scheduling

On the design of output feedback excitation controllers of synchronous machines