Four subjects were exposed to the four trial types that define stimulus equivalence from the beginning of the experiment. Procedures were designed to identify acquisition dynamics and relate these observations to responding indicative of equivalence class formation. The data show that, for all subjects, the acquisition of training conditional discriminations was correlated with systematic changes in the subjects' selection responses. The results also indicate that the traditional percent correct measures obscure some important information about the subjects' behavior. The data are discussed in the context of the following statements. 1) Subjects' performances on derived trials are not indicative of relations among stimuli at some other level of analysis but are instances of "equivalencing". 2) "Equivalencing" itself can be characterized as changes in the conditional and conditionally discriminative functions of stimuli involved in the experiment. The potential benefits of this preparation are discussed.

Beginning the study with a regional network map with an intent to perform a detailed harmonic study for a certain location, the first question that comes up is how far out in the system should detailed modeling of individual devices (transmission lines, loads, transformers, capacitor banks, etc) be done. The reason why this is extremely important is because system components that will affect the frequency response characteristics in the specific location should not be missed or poorly modeled. Frequency scan is the simplest and most commonly used simulation technique used to characterize the response of a power system network as a function of frequency. Unfortunately, there are two major problems using frequency scan techniques when real harmonic studies are considered: 1) the size of the admittance matrices (this calculation is repeated using discrete frequency steps throughout the range of interest) may be so large that an exact mathematical model of the system is not realistic and 2) the complexity of a rigorous and complete mathematical model of the system does not necessarily explain the extent to which system components affect the frequency response characteristics in a specified location. It is seldom clear how much of the system must be represented in order to get accurate results in a harmonic study. Realistic procedures to identify whether to include a particular element in a detailed model or to lump the element into a simplifying equivalent are yet to be developed in the industry. It is safe to say that practicing engineers are using tools and techniques of questionable validity. Two new computer-oriented methods that use eigen analysis techniques to identify easily and accurately the boundary between system areas to be modeled in detail and those represented by equivalents are proposed in this dissertation. The key here is to recognize that not all elements present in the ?external? system will participate in the resonant harmonic modes and could therefore be lumped into a simplified short-circuit equivalent. Achieving these objectives from either one of the two methods can be economically attractive. In short, the work described in this dissertation is a fundamentally sound alternative for the purposes of network equivalencing and model reduction.

Electrical energy is one of the most common forms of energy these days. Consequently, electric power system is an indispensable part of any society. However, due to the deregulation of electricity markets and the growth in the share of power generation by uncontrollable renewable energies such as wind and solar, power system simulations are more challenging than earlier. Thus, new techniques for simplifying these simulations are needed. One important example of such simplification techniques is the power system reduction. Power system reduction can be used at least for four different purposes: a) Simplifying the power system simulations, b) Reducing the computational complexity, c) Compensating the data unavailability, and d) Reducing the existing uncertainty. Due to such reasons, power system reduction is an important and necessary subject, but a challenging task to do. Power system reduction is even more essential when system operators are facing very large-scale power systems and when the renewable energy resources like hydro, wind, and solar have a high share in power generation. This thesis focuses on the topic of large-scale power system reduction with high penetration of renewable energy resources and tries to pursue the following goals: • The thesis first reviews the different methods which can be used for simplifying the power system studies, including the power system reduction. A comparison among three important simplification techniques is also performed to reveal which simplification results in less error and more simulation time decrement. • Secondly, different steps and methods for power system reduction, including network aggregation and generation aggregation, are introduced, described and discussed. • Some improvements regarding the subject of power system reduction, i.e. on both network aggregation and generation aggregation, are developed. • Finally, power system reduction is applied to some power system problems and the results of these applications are evaluated. A general conclusion is that using power system simplification techniques and specially the system reduction can provides many important advantages in studying large-scale power systems with high share of renewable energy generations. In most of applications, not only the power system reduction highly reduces the complexity of the power system study under consideration, but it also results in small errors. Therefore, it can be used as an efficient method for dealing with current bulk power systems with huge amounts of renewable and distributed generations. / <p>The Doctoral Degrees issued upon completion of the programme are issued by Comillas Pontifical University, Delft University of Technology and KTH Royal Institute of Technology. The invested degrees are official in Spain, the Netherlands and Sweden, respectively. QC 20150116</p>