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This study presents a methodology and the necessary analytical tools to evaluate the alternatives to provide Internet access with embedded power generation in remote areas. The objective is to provide a screening tool for policy makers to analyze possible telecom and power alternatives. Results from the study demonstrate the technical alternatives to providing sustainable Internet and power access. The dissertation investigates innovative telecom technologies currently available on the market, and develops a model that generates a Telecom-and-Internet access map of a region or a small country. The map illustrates the combination of technologies and their locations that can provide wide-area Internet access to cover a majority of the population at the least cost. The model then looks at the design of a small-scale power system for a remote location where grid power is unavailable or unreliable. The methodology takes into account locally available energy resources, technical and economic parameters of each power generating technology, and the trade-off among investment costs, environmental costs and system robustness. Lastly, a computer simulation is conducted to verify that the power system design has the ability to meet the demand at the level of required reliability. A remote area of a developing country (Chittagong and Chittagong Hill Tracts - Bangladesh) is selected as a case study. Several scenarios are simulated in order to explore the possibility of extending the reach of the Internet and electric power to the remote area, and to conceptualize pilot projects as building blocks to build a countrywide infrastructure. Since the selected area is one of the least developed and most difficult to access in Bangladesh, demonstrating that the Internet and local power access can be provided to this area can serve as a model for similar places around the world. / Ph. D.

As the world's energy use continues to grow, the development of clean distributed generation becomes increasingly important. Fuel cells are an environmentally friendly renewable energy source that can be used in a wide range of applications and are ideal for distributed power applications. In this study, the power conversion element of a dual single-phase, 10 kW stand-alone fuel cell system is analyzed. The modular converter consists of a DC-DC front-end cascaded with a half-bridge inverter. The entire system is accurately modeled, to help determine any interactions that may arise. Control strategies based on simplicity, performance, and cost are evaluated. A simple voltage loop, with careful consideration to avoid transformer saturation, is employed for the phase-shifted DC-DC converter. Several experimental transfer functions were measured to confirm the modeling assumptions and verify the control design of the DC-DC converter. Two control options for the inverter are explored in detail, and experimental results confirm that the modulation index must be controlled to regulate the output voltage during various load conditions. The final system is implemented without the use of current sensors, thus keeping the inverter cost down. Experimental results using a power supply are given for resistive, inductive, and nonlinear loads and the performance is acceptable. Fuel cell test results, including transient response, are also displayed and analyzed. / Master of Science

In this research, the impacts of installing DG on a residential distribution circuit are explored. The work is focused on analyzing the impact of DG installation on distribution network operation including voltage analysis, electric losses and reliability of the system. First, various DG penetration levels and the impact of distributing the DG across several locations are explored. Secondly, the impacts of installing DG on any one phase on the voltage profiles of the unbalanced three-phase distribution network are investigated. Thirdly, the losses of the system are analyzed. Next, the reliability analysis (SAIDI, CAIDI, ENS, and AENS) of the system is performed by installing DGs as backup generators. Different DG penetration levels, locations and the impacts of installing one large-scale DG on the main distribution line vs. several small-scale randomly distributed DGs are explored. A residential distribution circuit in Blacksburg, VA was built using its one-line diagram in DEW (Distributed Engineering Workstation) to perform detailed analysis. The research involves several case studies that explore the impacts of installing distributed generation (DG) on residential distribution network operation including the voltage profile, losses, and reliability indices of the system. / Master of Science

The aim of this work is to research the issue of optimal sizing and location of photovoltaic distributed generation (PVDG) units on radial distribution feeders, and develop new procedures by which the optimal location may be determined. The procedures consider the concept that the PVDG production varies independently from changes in feeder load demand. Based on that, the developed procedures deal with two performance curves; the feeder daily load curve driven by the consumer load demand, and the PVDG daily production curve driven by the solar irradiance. Due to the mismatch in the profile of these two curves the PVDG unit might end up producing only part of its capacity at the time the feeder meets its peak load demand. An actual example of that is the summer peak load demand in Abu Dhabi city that occurs at 5:30 pm, which is 5 hours after the time the PV array yields its peak. Consequently, solving the optimization problem for maximum line power loss reduction (∆PPL) is deemed inappropriate for the connection of PVDG units. Accordingly, the procedures have been designed to solve for maximum line energy loss reduction (∆EL). A suitable concept has been developed to rate the ∆EL at one time interval over the day, namely feasible optimization interval (FOI). The concept has been put into effect by rating the ∆EL in terms of line power loss reduction at the FOI (ΔPLFOI). This application is deemed very helpful in running the calculations with no need to repeat the energy-based calculations on hourly basis intervals or even shorter. The procedures developed as part of this work have been applied on actual feeders at the 11kV level of Abu Dhabi distribution network. Two main scenarios have been considered relating to the avoidance and allowance of reverse power flow (RPF). In this course, several applications employing both single and multiple PVDG units have been solved and validated. The optimization procedures are solved iteratively. Hence, effective sub-procedures to help determine the appropriate number of feasible iterative steps have been developed and incorporated successfully. Additionally, the optimization procedures have been designed to deal with a 3-phase feeder under an unbalanced load condition. The line impedances along the feeder are modeled in terms of a phase impedance matrix. At the same time, the modeling of feeder load curves along with the power flow calculations and the resulting losses in the lines are carried out by phase. The resulting benefits from each application have been evaluated and compared in terms of line power loss reduction at the FOI (∆PLFOI) along with voltage and current flow profile.

The rise of environmental awareness as well as the unstable global fossil fuel market has brought about government initiatives to increase electricity generation from renewable energy sources. These resources tend to be geographically and electrically remote from load centres. Consequently many Distributed Generators (DGs) are expected to be connected to the existing Distribution Networks (DNs), which have high impedance and low X/R ratios. Intermittence and unpredictability of the various types of renewable energy sources can be of time scales of days (hydro) down to seconds (wind, wave). As the time scale becomes smaller, the output of the DG becomes more difficult to accommodate in the DN. With the DGs operating in constant power factor mode, intermittence of the output of the generator combined with the high impedance and low X/R ratios of the DN will cause voltage variations above the statutory limits for quality of supply. This is traditionally mitigated by accepting increased operation of automated network control or network reinforcement. However, due to the distributed nature of RES, automating or reinforcing the DN can be expensive and difficult solutions to implement. The Thesis proposed was that new methods of controlling DG voltage could enable the connection of increased capacities of plant to existing DNs without the need for network management or reinforcement. The work reported here discusses the implications of the increasing capacity of DG in rural distribution networks on steady-state voltage profiles. Two methods of voltage compensation are proposed. The first is a deterministic system that uses a set of rules to intelligently switch between voltage and power factor control modes. This new control algorithm is shown to be able to respond well to slow voltage variations due to load or generation changes. The second method is a fuzzy inference system that adjusts the setpoint of the power factor controller in response to the local voltage. This system can be set to respond to any steady-state voltage variations that will be experienced. Further, control of real power is developed as a supplementary means for voltage regulation in weak rural networks. The algorithms developed in the study are shown to operate with any synchronous or asynchronous generation wherein real and reactive power can be separately controlled. Extensive simulations of typical and real rural systems using synchronous generators (small hydro) and doubly-fed induction generators (wind turbines) have verified that the proposed approaches improve the voltage profile of the distribution network. This demonstrated that the original Thesis was true and that the techniques proposed allow wider operation of greater capacities of DG within the statutory voltage limits.

In many developing countries, the electricity system is too weak to meet growing demand and the availability and reliability of generating capacity is inadequate. Protracted mismanagement, political interference, subsidised pricing, and corruption all undermine the ability of developing electricity supply industries to finance and deliver service or attract new private investment. Power sector reform is an acute need in developing countries where implementation of a top-down liberalisation approach has been pursued without adequately considering the social, political and economic conditions. The conventional response to low levels of electricity sector investment has been from the top-down: aim to create competitive electricity markets by encouraging new entry into the generation sector and by breaking up vertically integrated power companies. Using a case study from Gujarat, India, this thesis argues for an alternative approach—utilise distributed generation (DG) and captive power capacity (self-generation) of industry to reshape the generation and distribution sectors from the bottom-up. The thesis examines the economic viability of distributed generation in a rural setting and captive power for industrial use in Gujarat, India, taking into account the economic, technical and political factors that shape investment decisions. In India, 40 percent of the population still does not have an electricity connection, but an array of new energy technologies for small-scale electricity generation near the site of use may provide a new development path. The bottom-up model enables rapid addition of generation capacity to a system struggling to meet demand while increasing competition in the power market. The thesis concludes that more power from independent and industrial sources will best harness the financial and engineer resources of the Indian electricity supply industry (ESI) and ultimately benefit the economy. The solution proposed is not suggested as an optimal policy programme, but instead is advanced as the best of the feasible options available within current political and economic constraints.

Rise of the global environmental awareness and climate change impacts caused by greenhouse gases emissions brings about a revolution in the power and energy industries to reduce fossil fuels and promote low-carbon and renewable distributed generation (DG). The new dimensions, mainly encouraged by the governments’ legislative targets and incentives, have allowed the development of DG worldwide. In the U.K., renewable DG especially wind is being connected on distribution networks and ranges widely in scales. Despite the growing number of potential DG sites, the surplus generation present on the passive networks can lead to some technical problems. In particular, rural networks where wind farms exist are prone to voltage rise and line thermal constraints. In order to accommodate new DG and ensure security of supply and network reliability, active management to mitigate these issues are required. In addition, the duties to provide cost-effective DG connections at avoided expensive investment incurred from conventional solutions, e.g., reinforcement and maintain robust network are a major challenge for Distribution Network Operators (DNOs). This thesis endeavours to develop an adaptive control scheme that provides local and real-time management against voltage variations and line capacity overload at the point of wind connections on rural distribution networks. Taking into account maximising power exports and providing an economically-viable control scheme, the wind turbine’s capability, comprising reactive power control and active power curtailment, is used. Whilst the thesis concentrates on the decentralised control applying several different algorithms, in addition, semi-coordinated and centralised approaches that adopt on-load tap changing transformers’ regulation and Optimal Power Flow tool are developed. Comparisons of these approaches based upon measures, i.e., economics, DG penetration and performance are determined. As an outcome, the developed scheme can enable growing integration of renewable DG on distribution networks and can be seen as an interim solution for the DNOs towards Smart Distribution Networks.

In this thesis, a retail market mechanism that provides differentiated reliability services is proposed. The differentiated reliability services beyond the standard level utilize advanced metering infrastructure, automated distribution reconfiguration and distributed generation (DG). The service quality at the standard level is regulated, while high reliability services are offered through a market mechanism. This proposed market mechanism is designed in two different models of managing the distribution networks. The first model assumes that an independent distribution system operator (DSO) as an administrative firm provides operational support for delivery and reliability services in a retail market, while the second model does not have a DSO. Main reliability market participants are distribution utilities, retail electricity providers (REPs), non-utility-owned DG units, and end users. The REPs, as end users’ representatives and aggregators, purchase delivery service with high reliability level and backup power from the utilities and DG units, respectively. The prices for these services are based on bidding by all market participants. Bids are created by each market participant optimizing its objective with respect to its own interests; therefore, the market participant can assess the investment costs and manage its own risk in setting the service charge. Notably, the proposed market mechanism, which is based on knowing customers’ willingness to pay, and preferences for reliability, aims to give long-term investment signals to service providers for planning investments in new technologies at value. In addition, the provision of high reliability services can be considered a means that enables the service providers to improve system resilience. The modified IEEE Roy Billinton Test System Bus 2 is simulated to demonstrate proof-of-concept for the proposed retail market by showing the iii process of settling the service prices and utilities’ expected compensation design. By comparing the settled service prices between the two market models, we show that the service prices are quite similar, but the number of end users obtaining backup power is different.

The global market for photovoltaics (PV) has increased rapidly: during 2014, 44 times more was installed than in 2004, partly due to a price reduction of 60-70% during the same time period. Economic support schemes that were needed to make PV competitive on the electricity market have gradually decreased and self-consumption of PV electricity is becoming more interesting internationally from an economic perspective. This licentiate thesis investigates self-consumption of residential PV electricity and how more PV power can be allowed in and injected into a distribution grid. A model was developed for PV panels in various orientations and showed a better relative load matching with east-west-oriented compared to south-oriented PV panels. However, the yearly electricity production for the east-west-system decreased, which resulted in less self-consumed electricity. Alternatives for self-consumption of PV electricity and reduced feed-in power in a community of detached houses were investigated. The self-consumption increased more with shared batteries than with individual batteries with identical total storage capacity. A 50% reduction in feed-in power leads to losses below 10% due to PV power curtailment. Methodologies for overvoltage prevention in a distribution grid with a high share of PV power production were developed. Simulations with a case with 42% of the yearly electricity demand from PV showed promising results for preventing overvoltage using centralized battery storage and PV power curtailment. These results show potential for increasing the self-consumption of residential PV electricity with storage and to reduce stress on a distribution grid with storage and power curtailment. Increased self-consumption with storage is however not profitable in Sweden today, and 42% of the electricity from PV is far more than the actual contribution of 0.06% to the total electricity production in Sweden in 2014.