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Distribution system voltage and VAR control (VVC) is a technique that combines conservation voltage reduction and reactive power compensation to operate a distribution system at its optimal conditions. Coordinated VVC can provide major economic benefits for distribution utilities. Incorporating distributed generation (DG) to VVC can improve the system efficiency and reliability. The first part of this dissertation introduces a direct optimization formulation for VVC with DG. The control is formulated as a mixed integer non-linear programming (MINLP) problem. The formulation is based on a three-phase power flow with accurate component models. The VVC problem is solved with a state of the art open-source academic solver utilizing an outer approximation algorithm. Applying the approach to several test feeders, including IEEE 13-node and 37-node radial test feeders, with variable load demand and DG generation, validates the proposed control. Incorporating renewable energy can provide major benefits for efficient operation of the distribution systems. However, when the number of renewables increases the system control becomes more complex. Renewable resources, particularly wind and solar, are often highly intermittent. The varying power output can cause significant fluctuations in feeder voltages. Traditional feeder controls are often too slow to react to these fast fluctuations. DG units providing reactive power compensation they can be utilized in supplying voltage support when fluctuations in generation occur. The second part of this dissertation focuses on two new approaches for dual-layer VVC. In these approaches the VVC is divided into two control layers, slow and fast. The slow control obtains optimal voltage profile and set points for the distribution control. The fast control layer is utilized to maintain the optimal voltage profile when the generation or loading suddenly changes. The MINLP based VVC formulation is utilized as the slow control. Both local reactive power control of DG and coordinated quadratic programming (QP) based reactive power control is considered as the fast control approaches. The effectiveness of these approaches is studied with test feeders, utility load data, and fast-varying solar irradiance data. The simulation results indicate that both methods achieve good results for VVC with DG.

Embedded generation (EG) provides many benefits in terms of reduction of system technical losses and increased load carrying capacity. In this study the sustainable EG carrying capacity permutations in a medium voltage distribution system, will be determined. Using these results, the financial investment recovery potential of EG will be studied and the impact on the cost recovery by the Utility as a result of compensating the EG at the current system marginal price, will be analysed. The study was done to show what capitalisation can be done on a medium voltage distribution system, by the owners of EG plant receiving revenue from the Utility, at the system margin price with the anticipated inflationary increases. The study will also cover the effect on the revenue stream of the Utility as a result of voltage changes caused by the EGs to the loads being supplied. The electrical system used in the study consisted of a radial system with distributed load and generation. The distributed loads were modelled using the average load capacity supplied by the Utility in medium voltage system. The average volume of sales lost as a result of non-technical losses was included in the load model so that the overall accuracy of the revenue effect by EG on the Utility, could be increased. The amount of capitalisation that is achievable by the owners of the EG was tested against various practical permutation scenarios, including variation of location, system impedance (different X/R ratios), time of operation and changing load volume and type. The extent of successful penetration of EG into the distribution system was found to be between 20% and 60% of the load carrying capacity of the system. The simulated results revealed “bathtub curve” behaviour for the cost of energy losses and this reconciled with the theoretical analysis of other studies done in this area. Lower volume penetration of EG results in higher investment potential of up to ten million rand per MW with a 5% MARR per year. This is very low when compared to the levelised cost of the expensive renewable energy technologies that are currently available in the market. With higher penetration of EG on low impedance systems, the gross contribution of the Utility is negatively affected which would introduce instability in the SMP yearly increases. / M. Sc. Eng. University of KwaZulu-Natal, Durban 2013.

The objective of this thesis is to propose guidelines for advanced operation, control, and protection of the restructured distribution system by designing the architecture and functionality for autonomous operation of the distribution system with DGs. The proposed architecture consists of (1) autonomous state estimation and (2) applications that enable autonomous operation; in particular, three applications are discussed: setting-less component protection, instant-by-instant management, and short-term operational planning. Key elements of the proposed approach have been verified: (1) the proposed autonomous state estimation has been experimentally tested using laboratory test systems and (2) the feasibility of the setting-less component protection has been tested with numerical simulations.

Då ett eventuellt förbud av nya kreosotimpregnerade stolpar kan bli en verklighet inom EU år 2018 letar Vattenfall efter andra alternativ. Stål, betong, limträ och komposit anses idag vara de mest konkurrenskraftiga alternativen och kommer att undersökas i denna rapport. Grundläggande tekniska egenskaper, miljöutsläpp och kostnader för de olika stolptyperna kommer att analyseras i rapporten och jämföras mot den kreosotimpregnerade furustolpen. Rapporten beskriver hur de olika stolpalternativen lämpar sig i Vattenfalls elnät i Sverige. P.g.a. sekretesskäl kommer exakta prisuppgifter inte att redovisas. Prisuppgifterna för inköp och återvinning kommer istället att redovisas som en kvot mellan den alternativa stolpen dividerat kreosotstolpen. Inte heller kommer slipers och andra fundament att behandlas i rapporten. Metoden som används bygger på att först presentera relevant teori kring vardera stolptyp. Även impregneringsprocessen, besiktningsmetoder och nedbrytning/återvinning av stolpar redogörs i rapporten. Den miljömässiga analysen bygger på IVL Svenska Miljöinstitutets LCA-analys där kreosotstolpen jämförs med andra stolptyper. Det visar sig dock att kreosotstolpen är den stolptyp som bidrar till minst miljöutsläpp om man ser till hela dess livscykel. Slutsatsen är att kompositstolpen visar sig vara ett av de mest konkurrenskraftiga alternativen då den ses som ett miljövänligt alternativ och dess vikt gör den lätt att hantera. Den är heller inte impregnerad och kan därför monteras överallt utan några rättsliga restriktioner. Denna stolptyp är också väldigt aktuell då den i dagsläget är väl etablerad på marknaden. / Because of a possible ban of creosote impregnated poles can become a real scenario within the EU the year 2018 Vattenfall are searching for other alternatives. Steel, concrete, laminated wood and composite are considered the most competitive alternatives today and are being investigated in this report. Basic technical specifications, impacts on the environment and costs of the different pole types are being analyzed in the report and compared to the creosote impregnated pine pole. This report will describe how well the alternative pole types are suited in Vattenfalls electrical grid in Sweden. Due to confidentiality reasons the exact amount of costs and expenses will not be included in the report. The price of purchase and recycling will instead be presented as a quota between the alternative pole divided by the creosote pole. Neither will sleepers nor other pole foundations be included in this report. The method that is being used is to first present relevant theory about the mentioned pole types. Also the impregnation process, survey and disintegration/recycling of poles will be explained. The environmental analysis are based on IVL Svenska Miljöinstitutet's LCA where the creosote pole are compared to its alternatives. They conclude that it is the creosote pole that has the least impact on the environment if you look at the whole life-cycle. The conclusion is that the composite pole are shown to be one of the most competitive alternatives because it is considered to be environmental-friendly and its low weight makes it easy to work with. Also, it's not impregnated and can therefore be used everywhere without any legal restrictions. This pole type is also very relevant as it is already released on the market.

Deregulation is a growing trend and the electricity industry has not escaped its reaches. With worldwide experiences spanning only thirty years, there is substantial interest in analyzing current and future market designs so that market power cannot be used to increase the price of electricity significantly. / This thesis analyzes market power in electricity markets through the notion of Nash equilibrium (NE) and, more specifically, through Supply Function Equilibrium (SFE). We will examine how SFE can be modified to incorporate capacity constraints on generators and generating companies (gencos) controlling more than one generator for a Poolco electricity market with marginal pricing. / A genco's supply function is assumed to be of the form gi=l-aibi . Gaming is done either with ai or bi only, while keeping the other parameter at true cost. Gaming with both variables cannot be analyzed since the problem would have too many degrees of freedom. For each possible generator output level (minimum output, maximum output, or in between), analytical methods are employed to determine all candidate Nash equilibria. Then, simulations are performed over the range of possible genco offers to determine whether these candidates meet the complete set of Nash equilibrium criteria, specifically whether any genco can or cannot improve its profit by gaming. / For various inelastic demand levels, study cases indicate that there are either no Nash equilibria or only one. In the multi-unit genco case, the price of electricity is found to be higher than in the case where each genco owns only one generator, illustrating the effect of market concentration on the price. Whether capacity constraints are considered or not, the price of electricity appears to be higher if gencos are allowed to game with bi instead of ai. / The inclusion of capacity constraints on generators and the consideration of the multi-unit genco case will allow for better genco modeling in a Poolco market with marginal pricing. In turn, this will lead to more accurate analysis of the effects of current and possible rules and regulations on the price of electricity.

Since its introduction into mainstream society two decades ago, ecotourism has become an international phenomenon. Claimed by its proponents to endorse ecologically, socially, and economically sustainable travel to natural areas, ecotourism is in many ways the conceptual fusion of conservation and development. Yet, despite the optimism often associated with the phenomenon, the question of the degree to which it actually contributes to development, however defined, has become a controversial issue. Theorists and practitioners hold a variety of opinions of ecotourism, ranging from cautious optimism (Honey 2008; Ross & Wall 1999) to outright rejection (Carrier & Macleod 2005; Wheeller 2003). Unfortunately, research shows that the poorest of the poor generally bear the burden of ecotourism initiatives without receiving an equitable share of the associated benefits (Stem et al. 2003; Western & Wright 1994). In response, a sustainable livelihoods approach is proposed as a practical means of understanding the complex livelihood strategies employed by indigenous populations. While tourism research has often focused on the economic impacts of ecotourism initiatives, current livelihoods discourse suggests that the poor draw on a wide range of assets and incorporate a variety of livelihood strategies, in their pursuit of economic gain (Ashley 2002; Ashley et al. 2001; Bebbington 1999; Bennett et al. 1999; Zoomers 1999). This discourse is especially timely for pastoral populations living adjacent to protected areas in Kenya. Recent changes in government policy have promoted the subdivision of land for private ownership (Homewood et al. 2009; Leserogol 2005; Lamprey & Reid 2004), an unexpected transformation that has led to the adoption of ecotourism as a sustainable livelihood strategy. Informed by development theory, tourism theory, and property rights theory, the purpose of this research was to examine the effect of different land tenure regimes on the distribution of benefits accrued from various ecotourism initiatives, and how those benefits impact the livelihoods of the pastoral Maasai living on the periphery of the Maasai Mara National Reserve. Culturally-appropriate, participatory research methods were combined with the Sustainable Livelihoods Framework to document an indigenous perspective on livelihood sustainability. By adapting the conceptual framework to include cultural and historical capital, it served as a lens for viewing and identifying the culturally embedded meaning associated with the recent privatisation of Maasai property. These changes include: significant increases in income generated from ecotourism initiatives, an increased desire to cultivate land, an enhanced capacity for participating in the decision-making process, and greater diversification in local livelihood strategies. However, the empirical evidence also demonstrated that changing property regimes have led to the increased sedentarisation of these semi-nomadic people, resulting in modifications to their pastoral culture, reductions in their herd sizes, and the occasional obstruction of wildlife migratory patterns through the construction of permanent fences.

Some of the challenges associated with the multi-objective optimization on a modern power system were addressed in this work. Optimization of reactive resources was performed in order to simultaneously optimize several criteria: transmission losses, distribution losses, voltage stability, etc. The optimization was performed simultaneously on the entire power system; transmission and distribution subsystems included. The inherent physical complexity of modeling together transmission and distribution systems was considered first. After considering all pros and cons for such a task, a model of the entire power system was successfully developed. The inherent mathematical complexity of high-dimensional optimization space was handled by introducing the decoupling principle. System is first decoupled in several independent models and optimizations were performed on each part of the system. An algorithm is developed that properly combines the independent solutions to reach the overall system optima. The principle of algorithm synthesis is used to reduce the size of the solution space. Deterministic algorithms are used to locate the local optima which are subsequently refined by probabilistic algorithm. The algorithm is applied on a "real-life" test system and it is shown that the obtained solutions outperform the solution obtained with the conventional algorithms.

There are many calamitous events such as earthquakes, hurricanes, tsunamis etc. that occur suddenly and cause great loss of life, damage, or hardship. Hurricanes cause significant damage to power distribution systems, resulting in prolonged customer outages and excessive delays in the reconstruction efforts. Accordingly, predicting the effects of power outages on the performance of power distribution systems is of major importance to government agencies, utilities, and customers. Unfortunately, the current tools to predict the performance of power distribution systems during catastrophic events are limited in both the performance measures considered, as well as in their ability to model real systems. The main goal of this research is to develop a methodology for simulating hurricanes of different intensity on power distribution systems of small and medium size cities. Our study includes a detailed comparison between the engineering-based and connectivity-based models of power distribution systems, as well as the impact of power re-routing algorithms on the system reliability. Our approach is based on fragility curves that capture the ability of the system to withstand a range of wind speeds. In addition, we develop a multiscale approach that facilitates efficient computation of fragility curves for large cities. With this approach, hurricanes are simulated over small zones of a city and fragility curves are obtained. These are used to estimate the damage for identical zones throughout the city. To validate our techniques, two testbeds, Micropolis and Mesopolis, were used. Micropolis is synthetic model for a small city and Mesopolis for a big city. Obtained results have validated our approach and have shown that they can be used to effectively predict hurricane damage.

Electric power engineering, as it applies to low-voltage power reticulation in buildings and industrial sites, is ripe for a ‘paradigm shift’ to bring it properly into the Electronic Age. The conventional alternating-current approach, now over a hundred years old, is increasingly unsatisfactory from the point of view of plant and appliance requirements. Alternative approaches can deliver substantial cost savings, higher efficiencies, power quality improvements, and greater safety. Power reticulation systems in the future can be expected to differ from present systems in two key respects. The first is a greatly increased role for direct current; the second is the augmentation of the power system with a wide range of ‘management’ technologies. Combining these two trends, which can already be observed today, leads to consideration of ‘managed DC’ power reticulation systems, operating from AC bulk supply mains via AC-DC converters.