Capturing Transmission and Distribution Connected Wind Energy Variability

Although renewable energy provides a viable solution to address ongoing challenges of the economy and the environment in modern power systems, the variable generation of this technology results in major technical challenges for system operators. This issue is becoming more severe as the penetration of renewable generation is increasing. This dissertation addresses the variability challenge of renewable energy resources in transmission and distribution levels of modern power systems. For transmission level, this dissertation focuses on wind generation fluctuation. Three methods of reducing wind generation fluctuation are investigated from an economic perspective, including (a) dumping the wind generation, (b) using battery energy storage system (BESS) to capture excess wind generation, and (c) a hybrid method combining these two approaches. The economic viability of the hybrid method is investigated via a developed linear programming model with the objective of profit maximization, which in extreme cases will converge to one of the other methods. This dissertation further proposes a BESS planning model to minimize wind generation curtailment and accordingly maximize the deployment of this viable technology. For distribution level, this dissertation investigates the issue of microgrids net load variability stemmed from renewable generation. This is accomplished by investigating and comparing two options to control the microgrid net load variability resulted from high penetration of renewable generation. The proposed options include (a) Local management, which limits the microgrid net load variability in the distribution level by enforcing a cap constraint, and (b) Central management, which recommends on building a new fast response generation unit to limit aggregated microgrid net load variability in the distribution level. Moreover, the aggregated microgrid net load variability is studied in this dissertation by considering the distribution system operator (DSO). DSO would calculate the microgrids net load in day-ahead basis by receiving the aggregated demand bid curves. Accordingly, two models are proposed considering the DSO role in managing the grid operation and market clearing. The first one is security-constrained distribution system operation model which maximizes the system social welfare. The system security consists of distribution line outage as well as microgrid islanding. None of these two security events are in the control of the DSO, so associated uncertainties are considered in the problem modeling. The second one aims at reconfiguring the distribution grid, i.e., a grid topology control, using the smart switches in order to maximize the system social welfare and support grid reliability. The conducted numerical simulations demonstrate the effectiveness and the merits of the proposed models in identifying viable and economic options in capturing renewable generation variability

Arithmetic properties of overpartition functions with combinatorial explorations of partition inequalities and partition configurations

A thesis submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in ful lment of the requirements for the degree of Doctor of Philosophy. Johannesburg, 2017.In this thesis, various partition functions with respect to `-regular overpartitions, a special partition inequality and partition con gurations are studied. We explore new combinatorial properties of overpartitions which are natural generalizations of integer partitions. Building on recent work, we state general combinatorial identities between standard partition, overpartition and `-regular partition functions. We provide both generating function and bijective proofs. We then establish an in nite set of Ramanujan-type congruences for the `-regular overpartitions. This signi cantly extends the recent work of Shen which focused solely on 3{regular overpartitions and 4{regular overpartitions. We also prove some of the congruences for `-regular overpartition functions combinatorially. We then provide a combinatorial proof of the inequality p(a)p(b) > p(a+b), where p(n) is the partition function and a; b are positive integers satisfying a+b > 9, a > 1 and b > 1. This problem was posed by Bessenrodt and Ono who used the inequality to study a maximal multiplicative property of an extended partition function. Finally, we consider partition con gurations introduced recently by Andrews and Deutsch in connection with the Stanley-Elder theorems. Using a variation of Stanley's original technique, we give a combinatorial proof of the equality of the number of times an integer k appears in all partitions and the number of partition con- gurations of length k. Then we establish new generalizations of the Elder and con guration theorems. We also consider a related result asserting the equality of the number of 2k's in partitions and the number of unrepeated multiples of k, providing a new proof and a generalization.MT201

Microgrid Optimal Scheduling Considering Impact of High Penetration Wind Generation

The objective of this thesis is to study the impact of high penetration wind energy in economic and reliable operation of microgrids. Wind power is variable, i.e., constantly changing, and nondispatchable, i.e., cannot be controlled by the microgrid controller. Thus an accurate forecasting of wind power is an essential task in order to study its impacts in microgrid operation. Two commonly used forecasting methods including Autoregressive Integrated Moving Average (ARIMA) and Artificial Neural Network (ANN) have been used in this thesis to improve the wind power forecasting. The forecasting error is calculated using a Mean Absolute Percentage Error (MAPE) and is improved using the ANN. The wind forecast is further used in the microgrid optimal scheduling problem. The microgrid optimal scheduling is performed by developing a viable model for security-constrained unit commitment (SCUC) based on mixed-integer linear programing (MILP) method. The proposed SCUC is solved for various wind penetration levels and the relationship between the total cost and the wind power penetration is found. In order to reduce microgrid power transfer fluctuations, an additional constraint is proposed and added to the SCUC formulation. The new constraint would control the time-based fluctuations. The impact of the constraint on microgrid SCUC results is tested and validated with numerical analysis. Finally, the applicability of proposed models is demonstrated through numerical simulations

Statistical Analysis of CubeSat Mission Failure

There are multiple common reasons for CubeSats’ failure. These include power, mechanical, and communications issues. Some have suggested that the problem lies within the design and development process itself, in that universities and research institutions mainly focus on system and component level designs, while neglecting requirements’ elicitation needed beforehand. A survey was conducted during the 14th Annual CubeSat Workshop at CalPoly, San Luis Obispo, to identify the challenges and needs of such groups and initial results from this survey and its analysis are reported in this paper. This survey was conducted with students in the U. S. and Europe, working on small spacecraft development and majoring in disciplines including computer science and mechanical engineering. The survey considered multiple factors prospectively associated with mission success or failure, including the possibility of adding or deleting components into/from the system design and system modifications’ feasibility. Additionally, the respondents were asked the objectives of their CubeSat mission and whether their system design covered the entire system (e.g., structure, behavior, requirements, and system parametric). The problems identified by them related to tools, models, or both have also been reported. Finally, participants were asked whether they helped in reducing the system testing time or employed a CubeSat reference model. This paper concludes with a discussion regarding what has been learned from data analysis. Plans for future work are also discussed

Achieving global recognition: higher education rankings and the commitment to quality in Saudi Arabia’s 2030 Strategic Vision

This study has as a primary focus the devising of strategic recommendations to help the government of Saudi Arabia achieve its goals, particularly the objective of having at least five Saudi institutions among the top 200 global universities by 2030. The research explored the challenges in realizing the educational targets set in The Saudi Vision 2030, aiming to position Saudi Arabia as a global education leader. In examining the background of education in the Kingdom of Saudi Arabia, the study delves into the historical evolution of the education system and its alignment with contemporary aspirations, notably the Saudi Vision 2030. This comprehensive overview provides context for understanding the current higher education landscape and the imperative for transformation. The conceptualization of the western form of the university, from its origins as a Church institution to its evolution into a globalized modern entity, forms a backdrop to an understanding of the university of today. The concept of excellence in higher education is explored, tracing its trajectory from ancient universities to the present era. This examination encompasses the historical development of formal quality systems and the contemporary imperative for achieving world-class status. The development of higher education quality and quality assurance frameworks are considered. The study explores ranking systems in higher education, addressing their development, impact, and significance to improving institutional status and global position. With reference to a wider framework of neoliberalism and its globalizing affects, attention is given to how Saudi universities confront the complexities of global ranking systems and their implications for institutional advancement. By considering critical perspectives and emerging trends in ranking methodologies, the research identifies pathways for enhancing the global competitiveness of Saudi institutions. The study underscores the interconnectedness of historical legacies, contemporary challenges, and future aspirations in advancing Saudi higher education. By synthesizing insights from diverse domains, strategic recommendations are formulated to support Saudi universities towards global prominence, aligning with the ambitious vision outlined in Saudi Vision 2030. In addition to a review of the relevant literature, ten interviews were conducted with senior leaders from universities, Vice Rectors for Planning, Development, and Quality. The participants, from both the United Kingdom and Saudi Arabia, possessed practical and operational expertise in higher education ranking focused activity. This research identified crucial factors pivotal for advancing the higher education system towards its strategic goal. The study highlights the significant roles of academic research, the cultivation of research identity, marketing, publicity, financial resource attraction, academic and administrative autonomy, and academic reputation. These elements are collectively decisive to any effort to elevate the global rankings of Saudi universities. The research indicates areas recommended for enhancement in Saudi universities, including bolstering academic reputation, promoting research, investing in research and development, fostering international collaborations, and attracting international students

An optimal sizing framework for autonomous photovoltaic/hydrokinetic/hydrogen energy system considering cost, reliability and forced outage rate using horse herd optimization

The components outage of an energy system weakens its operation probability, which can affect the sizing of that system. An optimal sizing framework is presented for an autonomous hybrid photovoltaic/hydrokinetic/fuel cell (PV/HKT/FC) system with hydrogen storage to supply an annual load demand with forced outage rate (FOR) of the clean production resources based on real environmental information such as irradiance, temperature, and water flow. The sizing problem is implemented with the objective of cost of energy (COE) minimization and also satisfying probability of load supply (PLS) as a reliability constraint. The FOR effect of the photovoltaic and hydrokinetic resources is evaluated on the hybrid system sizing, energy cost, reliability, and also storage contribution of the system. Meta-heuristic horse herd optimization (HHO) algorithm with perfect capability on exploration and exploitation phases is used to solve the sizing problem. The results proved that the PV/HKT/FC configuration is the optimal option to supply the demand of an autonomous residential complex with the minimum COE and maximum PLS compared with the other system configurations. The results demonstrated the overlap of hydrogen storage with clean production resources to achieve an economic-reliable power generation system. The findings indicated that the COE is increased and the PLS is decreased due to the FOR increasing because of reducing the generation resources operational probability. The results demonstrated that the hydrogen storage level is increased with FOR increasing to maintain the system reliability level. Also, the sizing results indicated that the FOR of the hydrokinetic is more effective than the photovoltaic resources in increasing the system cost and undermining the load reliability. In sizing of the hybrid PV/HKT/FC system, the COE is obtained 1.57 $/kWh without considering the FOR and is achieved 1.66 and 1.63$/kWh considering the FOR (8%) for the hydrokinetic and photovoltaic resources, respectively. Moreover, the results cleared that the HHO is superior in comparison with particle swarm optimization (PSO), genetic algorithm (GA), and grey wolf optimizer (GWO) in the PV/HKT/FC system sizing with the lowest COE and higher reliability