Toward Fault Adaptive Power Systems in Electric Ships

Shipboard Power Systems (SPS) play a significant role in next-generation Navy fleets. With the increasing power demand from propulsion loads, ship service loads, weaponry systems and mission systems, a stable and reliable SPS is critical to support different aspects of ship operation. It also becomes the technology-enabler to improve ship economy, efficiency, reliability, and survivability. Moreover, it is important to improve the reliability and robustness of the SPS while working under different operating conditions to ensure safe and satisfactory operation of the system. This dissertation aims to introduce novel and effective approaches to respond to different types of possible faults in the SPS. According to the type and duration, the possible faults in the Medium Voltage DC (MVDC) SPS have been divided into two main categories: transient and permanent faults. First, in order to manage permanent faults in MVDC SPS, a novel real-time reconfiguration strategy has been proposed. Onboard postault reconfiguration aims to ensure the maximum power/service delivery to the system loads following a fault. This study aims to implement an intelligent real-time reconfiguration algorithm in the RTDS platform through an optimization technique implemented inside the Real-Time Digital Simulator (RTDS). The simulation results demonstrate the effectiveness of the proposed real-time approach to reconfigure the system under different fault situations. Second, a novel approach to mitigate the effect of the unsymmetrical transient AC faults in the MVDC SPS has been proposed. In this dissertation, the application of combined Static Synchronous Compensator (STATCOM)-Super Conducting Fault Current Limiter (SFCL) to improve the stability of the MVDC SPS during transient faults has been investigated. A Fluid Genetic Algorithm (FGA) optimization algorithm is introduced to design the STATCOM\u27s controller. Moreover, a multi-objective optimization problem has been formulated to find the optimal size of SFCL\u27s impedance. In the proposed scheme, STATCOM can assist the SFCL to keep the vital load terminal voltage close to the normal state in an economic sense. The proposed technique provides an acceptable post-disturbance and postault performance to recover the system to its normal situation over the other alternatives

PRZEGLĄD METOD REGULACJI NAPIĘCIA W SIECIACH ELEKTROENERGETYCZNYCH NISKIEGO NAPIĘCIA Z DUŻYM UDZIAŁEM GENERACJI ROZPROSZONEJ

Deterioration of voltage conditions is one of the frequent consequences of connecting an increasing number of photovoltaic sources to the low-voltage (LV) power grid. Under adverse conditions, i.e. low energy consumption and high insolation, microgeneration can cause voltage surges that violate acceptable limits. Research shows that the increase in voltage is the main limitation for connecting new energy microsources to the LV network and forces the reconstruction of the network. An alternative to costly modernizations can be the implementation of appropriate strategies for controlling network operation to maintain the voltage at the required level. The article presents an overview of the methods and concepts of voltage control in a low-voltage network developed so far to mitigate the undesirable phenomenon of voltage boosting. The focus was mainly on local methods—not requiring communication infrastructure—as best suited to the conditions of Polish distribution networks. Gathering the results of many tests and simulations carried out in different conditions and on different models allowed for the formulation of general conclusions and can be a starting point for further research on a control method that can be widely used in the national power system.Jedną z częstych konsekwencji przyłączania do sieci elektroenergetycznej niskiego napięcia (nn) coraz większej liczby źródeł fotowoltaicznych jest pogorszenie warunków napięciowych. W niesprzyjających warunkach – przy niskim poborze energii i wysokim nasłonecznieniu – mikrogeneracja może powodować podskoki napięcia przekraczające dopuszczalne granice. Badania pokazują, że wzrost napięcia stanowi podstawowe ograniczenie dla przyłączania nowych mikroźródeł energii do sieci nn i wymusza przebudowę sieci. Alternatywą dla kosztownych modernizacji może być wdrożenie odpowiednich strategii sterowania pracą sieci pozwalających utrzymać napięcie na wymaganym poziomie. W artykule zaprezentowano przegląd opracowanych dotychczas metod i koncepcji regulacji napięcia w sieci nn mających na celu opanowanie niepożądanego zjawiska podbicia napięcia. Skupiono się głównie na metodach lokalnych – nie wymagających do prawidłowego działania infrastruktury komunikacyjnej – jako najlepiej przystosowanych do warunków polskich sieci dystrybucyjnych. Zebranie wyników badań i symulacji, przeprowadzonych przy różnych założeniach i na różnych modelach, pozwoliło na sformułowanie ogólnych wniosków i może stanowić punkt wyjścia do dalszych badań nad metodą sterowania mogącą znaleźć szerokie zastosowanie w krajowym systemie elektroenergetycznym

Getting Smart (Grids): An Efficiency Frontier Assessment

Information and communication technology are reshaping the electricity industry, with economic, environmental, and regulatory consequences. Smart grids allow the growing integration of renewable energy sources, a horizontalization of the roles of producers and consumers, a flatter demand profile which save investments intended to supply peaks of consumption, idle at great extent off-peaks. On the other hand, smart grids require important investments for modernizing technology. Concerning our objectives, firstly, we seek to understand the conceptual consequences of the irruption of smart grids on the electricity sector, and its importance for renewables adoption. Secondly, we discuss policies and regulations needed to accelerate the transformation of the electricity network in a smart grid, and to increase the renewables? share on total energy. Thirdly, our empirical approach runs a Data Envelopment Analysis (DEA) model to estimate the efficiency gains in the transition between traditional and smart grids. Our results show the efficiency levels of those countries whose objective is to deliver electricity with high levels of quality of services, and at the same time, using more renewables (with fewer carbon emissions), and low cost of supply. We conclude discussing the implications of our empirical model, the limitations, and next stages in polishing the results.Fil: Ferro, Gustavo Adolfo. Universidad del Cema; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Romero, Carlos Adrián. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto Interdisciplinario de Economía Política de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Económicas. Instituto Interdisciplinario de Economía Política de Buenos Aires; ArgentinaFil: Ramos, Maria Priscila. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto Interdisciplinario de Economía Política de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Económicas. Instituto Interdisciplinario de Economía Política de Buenos Aires; ArgentinaLV Reunión Anual Asociación Argentina de Economía PolíticaCiudad Autónoma de Buenos AiresArgentinaAsociación Argentina de Economía Polític