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The analysis and characterization of the steady-state security of a bulk-power electric system is investigated in a region-wise or set-theoretic framework. The study is divided into three parts: a detailed examination of the theoretical aspects of general security regions; a formulation and analysis of the problem of characterizing a set of secure operating points by a simple, explicit function; and an investigation into the secure loadability of a power system. Based on the results of the theoretical study, general approximate relations expressing dependent load flow variables in terms of the nodal injections are derived. Their degree of accuracy and extent of validity are investigated through analytical and simulation-based analyses. The general problem of characterizing subsets of a security region by simple, explicit functions is formulated as an optimization problem. For the case where the subsets are expressed by ellipsoids, two algorithms are developed and tested. The problem is then extended to include embedding the largest ellipsoid of a £ixed orientation inside a security region. The application of explicit security sets to the problem of predictive security assessment is studied in detail. A number of explicit security subsets overlapping along the predicted daily trajectory is used to define a "security corridor". This predicted corridor has the property that as long as the actual trajectory stays within it, very little computation is needed to assess the system security. The secure loadability of a power system is first studied in the demand space by considering the orthogonal projection of security sets into that space. It is then studied in the voltage space in the context of existence of a secure load flow solution to a given loading condition. Properties of the set of secure voltage solutions are explored by enclosing it with a linear set. Furthermore, it is shown that, under favorable conditions, one can easily characterize a subset of the set / L'analyse et la caracterisation de la securite en regime permanent pour un reseau et transmission ont ete etudiees dans le contexte de la theorie des ensembles. L'etude est divisee en trois parties: un examen detaille: des aspects theoriques des regions de securite generale; la formulation et l'analyse de probleme de la caracterisation d'un ensemble de points de fonctionnement par une fonction simple, sous forme explicite, et l'etude de la capacite de charge d'un reseau. Une analyse theorique a permis de deriver des relations approximative generales, exprimant les variables dependantes de l'ecoulement de puissance en terme des injections de noeud. Le degre de precision de ces approximations ainsi que leurs limites d'application sont determinees a l'aide de simulations et d'analyses theoriques. Le probleme general de la caracterisation des sous-ensembles d'une region de securite par des fonctions simples et sous forme explicite est formule comme probleme d'optimisation. Dans le cas ou les sous-ensembles sont exprimes par des ellipsoides, deux algorithmes sont developpes et verifies. Le probleme est alors elargi de facon a inclure le plus grand ellipsoide d'orientation fixe a l'interieur d'une region de securite. L'application d'ensembles de securite au prob1eme de l'evaluation preventive est etudiee en detail. On utilise un certain nombre d'ensembles de securite se recoupant long de la trajectoire journaliere prevue de facon a definir un corridor de securite. Ce corridor prevu possede la propriete qu'aussi longtemps que la trajectoire y est confinee, un minimum de calculs est requis pour evaluer la securite du systeme. Le chargement securitaire d'un reseau est en premier lieu etudie en considerant la projection orthogonale des ensembles de securite sur cet espace. Il est ensuite etudie dans l'espace des tensions, dans le contexte de l'existence d'une solution pour une charge donnee. Les proprietes de l'ensemble des solutions securitaires sont explorees en l'enchas

Thesis (M.A.A.S.) -- Air University, 2004. / Title from PDF title page (viewed on April 24, 2009). "June 2004." Includes abstract. Includes bibliographical references (leaves 75-82).

Thesis (M.S. in Joint Campaign Planning and Strategy)--Joint Forces Staff College, Joint Advanced Warfighting School, 2006. / "14 April 2006." Electronic version of original print document. Includes bibliographical references (p. 71-77).

Thesis (M.S. in Joint Campaign Planning and Strategy)--Joint Forces Staff College, Joint Advanced Warfighting School, 2007. / Title from title screen; viewed on July 9, 2007. "5 April 2007." Electronic version of original print document. Includes bibliographical references (p. 125-131).

Thesis (M.S.)--Oregon State University, 2008. / Printout. Includes bibliographical references (leaves 125-126). Also available on the World Wide Web.

The current research is motivated by the controversy between the proponents and opponents of privatizing SOEs in LDCs concerning its impact on the MCSs designed and implemented in these companies. On the one hand, proponents expect privatization to foster the design and implementation of market-based, consensual and transparent MCSs. On the other hand, opponents are more critical about the ‘actual’ changes that privatization might entail to SOEs’ MCSs as they expect it to entail the design and implementation of non-transparent, coercive MCSs. When examined closely, this conflict was found to be rooted in the different theoretical perspectives adopted by each side. While proponents base their arguments, mostly, on ‘traditional’ agency and property-rights theories that underplay the role of structure in shaping the MCSs designed and implemented in privatized companies, many of the opponents base their arguments on neo-Marxist theories that underplay the role of agency in that process (namely labour process theory- LPT). The current research contributes to this debate through developing a power-informed theoretical model that acknowledges the role of both agency and structure in shaping the nature of the pre- and post-privatization MCSs designed and implemented in companies operating in LDCs. The model provides an attempt to develop the Hopper et al (2009) model through integrating into it a theory of power informed by the works of Lukes (1974 and 2005) and Gaventa (1980 and 2007) while adopting the integrative agency-structure approach suggested by Mahoney and Snyder (1999).Once developed, the model is used to guide the analysis of the relevant literature pertaining to Egypt’s supra-national and national power relations and structural factors throughout its state and market capitalism eras as a first step towards comparatively analysing the pre- and post-privatization power relations and MCSs manifesting in two Egyptian companies. The empirical data was mainly collected through conducting semi-structured interviews in the two companies and with some of the government officials involved in their privatization. Other sources of data include the companies’ internal records and financial reports, government publications, and newspapers. The comparative analysis shows how the power-informed model can help shed more light onto the nature of, and the dynamics of change in, MCSs transformations in LDCs; without having to abandon LPT as one of the main theoretical perspectives informing the analysis. While doing so, the nature of a company’s MCSs (be it coercive, consensual, or irrelevant) is found to reflect the power relations manifesting in that company (namely, powerful management, comparatively powerful management and labour, or powerful labour, respectively). Furthermore, as the comparative analysis shows, it is found that privatization is more likely to result in changing the nature of a SOE’s MCSs when it entails altering the power relations shaping these MCSs.

M.Ing. (Electrical and Electronic Engineering) / Shunt reactors are used in power system amongst other things, to suppress overvoltages in the network during network switching, auto reclosing of transmission lines and under low loading condition of the network. Traditionally, shunt reactors of fixed type have been used and these have been permanently connected to the system. This research work investigated the feasibility of replacing the fixed shunt line reactors with a reactor, whose parameters are automatically varied depending on the system reactive power requirements, in a mature power system overlaid with high voltage lines to improve amongst, other things voltage stability. However, in a mature system overlaid with parallel higher voltage lines, power tend to flow on the matured system rather than higher voltage system as predetermined by various impedances of the power system. It is therefore desirable that loading of higher voltage lines be increased because of their higher power transfer capability and fact that higher voltage networks generate capacitive power which is substantially more than for each line at the original voltage. However, replacing a large number of fixed line reactors, at low loadings of higher voltage lines, even when system collapse is averted by increasing the number of reactors inserted into the system, overvoltage problems may still be an issue, until a certain number of must-run reactors, operating at full reactance, are put into service. If too much inductive reactance is removed from the system when the loading levels are extremely low, the power system will collapse. Therefore, there was no economic benefit in replacing all the fixed shunt line reactors with controllable type when the loading was still relatively low. Thus, the majority of the converted reactors were operating in their full rating as there was still more reactive power to be absorbed. However, when the power was diverted to flow on the higher voltage system through the use of series compensation of the higher voltage system, there was a possibility of making some fixed shunt line reactors on the higher voltage network controllable. This also allowed more power to be transferred in the higher voltage system thus improving its utilisation. Also, a positive impact on active system losses was realised.

Transient stability analysis is an important part of power planning and operation. For large power systems, such analysis is very time consuming and expensive. Therefore, an online transient stability assessment will be required as these large power systems are operated close to their maximum limits. In this thesis swallowtail catastrophe is used to determine the transient stability regions. The bifurcation set represents the transient stability region in terms of power system transient parameters bounded by the transient stability limits. The system modelling is generalized in such, that the analysis could handle either one or any number of critical machines. This generalized model is then tested on a three-machine as well as a seven-machine system. The results of the stability analysis done with the generalized method is compared with the time solution and the results were satisfactory. The transient stability regions determined are valid for any changes in loading conditions and fault location. This method is a good candidate for on-line assessment of transient stability of power systems. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate

The Aim of this study is to examine violence in close relationship and to explore the different explanation on men's violence as well as the factors that contribute to their violent behavior. Violence in close relationships can occur in different forms and anyone can fall as a victim of both physical and mental abuse. Violence and discrimination against women violates the principles of equal rights and respect for human dignity. In Sweden, men's violence against women and violence in close relationships is still a major problem that requires great work and attention. It is one of Sweden's responsibility to meet all people's equal values and rights and to fight violence in close relationship.