S. A. Soliman

Measurement of power systems voltage and flicker levels for power quality analysis: a static LAV state estimation based algorithm

There is a need to accurately measure voltage flicker levels for power quality analysis. This paper introduces a new application of the least absolute value (LAV) state estimation algorithm to measure the flicker voltage magnitude as well as the voltage magnitude. The problem ends up as one of linear optimization, for which we use the LAV parameter estimation algorithm. We use a linear model of the flicker voltage magnitude as well as the power system voltage magnitude and their phase angles. The proposed algorithm uses digitized samples of the voltage signal. Effects of data window size, sampling frequency and number of samples on the estimated voltages magnitudes and phase angles are investigated.

Load flow solution of radial distribution feeders: a new contribution

Abstract This paper presents a new development for solving the load flow problem for radial distribution feeders, without having to solve the well-known conventional load flow equations. The algorithm details are discussed. Two test radial distribution feeders are solved using the proposed development to illustrate the technique. The tables of solution variables such as voltage, injected powers at each node of the feeder and line losses are presented along with comments and conclusions. The performance of the proposed development is also evaluated for a number of feeders that were studied and solved using earlier methods. Also the method is compared with the original method from Baran and Wu (IEEE Trans. Power Delivery 4(1) (1989) 735–743) as well as the standard conventional load flow methods.

Dynamic Optimal Load Flow

The load flow problem in an electric power system is concerned with solving a set of static nonlinear equations describing the electric network performance. The problem is formulated on the basis of Kirchhoff’s laws in terms of active and reactive power injections and voltages at each node in the system. Presently, the load flow program is a major tool for the electric power systems engineer in carrying out diverse functions in the planning and operation of the system. This topic is treated in detail in many introductory electric power systems textbooks (Refs. 3.1–3.4).

Efficient load—following scheduling with application to the B.P.A. hydro-electric system

Abstract An efficient algorithm for solving the load following scheduling problem is presented for large scale hydro-electric power systems, to obtain a maximum and most uniform surplus power, while satisfying the various environmental, physical, legal and contractual constraints. The proposed algorithm is based on the minimum norm formulation of functional analysis, and takes into account the variations of tail water elevation and forebay elevation. The proposed technique is applied to solve the optimal long-term load following scheduling problem of the Bonneville Power Administration (B.P.A.) system which is one of the largest hydro systems in the world. Numerical results are reported and the results obtained are compared using the proposed algorithm and the B.P.A. results. The results are promising.

Optimization of the load-following scheduling problem of the B.P.A. hydro-electric system

Abstract This paper presents an efficient algorithm used for solving the load following scheduling problem, for large scale hydro-electric power systems, to obtain a maximum and most uniform surplus power, while satisfying the various environmental, physical, legal and contractual constraints. The proposed algorithm is based on the minimum norm formulation of functional analysis, and it takes into account the variations, of tail water elevation and forebay elevation. The proposed technique is applied to solve the optimal long-term load following scheduling problem of the Bonneville Power Administration (B.P.A.) hydro-electric system which is considered to be one of the largest hydro systems in the world. Numerical results are reported and compared with results. They show considerable promise.

Optimal Control of Turboalternators

This chapter is devoted to the solution of the problem of optimal control of synchronous turboalternators. In the first section of this chapter the optimal torque and voltage control of a large turbogenerator connected to an infinite bus is found by using the minimum norm formulation. In the second section the optimal control of a system with two identical interconnected turbogenerators connected to an infinite bus is considered. Control of the generators is effected through control of field voltages and turbine torques. Finally, in the last section a realistic feedback control of two interconnected turbogenerators is considered.

Some Optimal Control Techniques

The intent of this chapter is to introduce fundamental concepts of optimal control theory that are relevant to the applications treated in the following Chapters. Emphasis will be given to clear, methodical development rather than rigorous formal proofs. The fundamental conditions of the variational calculus for dynamic system optimization are discussed in Section 2.2. A brief summary of Pontryagin’s maximum principle is given in Section 2.3. In Section 2.4 the functional analytic technique of formulating optimization problems in the minimum norm form is dealt with. A brief treatment of some basic concepts from functional analysis is given prior to stating one powerful version of minimum norm problems.

Economic Coordination of Hydrothermal—Nuclear Systems

It is the purpose of this chapter (1) to formulate the problem of optimal short-term operation of hydrothermal-nuclear systems, (2) to obtain the solution by using a functional analytic optimization technique that employs the minimum norm formulation, and (3) to propose an algorithm suitable for implementing the optimal solution.

Optimal Tie-Line Control

For more than two decades, the problem of load frequency control (LFC) using conventional or advanced-control theory has been the subject of numerous studies. The conventional LFC approach often employs what is called the tie-line bias concept to design a system controller that has a proportional-plus-integral (PI) action. This type of control is used extensively in practice in preference to all the techniques that have been proposed recently, employing modern control theory. The reason for that is that most recent techniques have developed linear feedback controls that are functions of all the system state variables as well as the system disturbances (Refs. 5.1, 5.2). Therefore, it was necessary to design an observer to realize these kind of controls (Ref. 5.3). Once an observer is introduced into the system, the cost is increased, and the control is no longer optimal (Ref. 5.4). Another important reason is that a control that depends upon all the system states needs some of these state variables to be telemetered, since the areas of interconnected power systems (IPS) are spread over large geographical territories. This is why, in practice, control engineers prefer to use the conventional control to the advanced one, in spite of the contention that the latter improves the system transient performance.