Active congestion quantification and reliability improvement considering aging failure in modern distribution networks

The enormous concerns of climate change and traditional resource crises lead to the increased use of distributed generations (DGs) and electric vehicles (EVs) in distribution networks. This leads to significant challenges in maintaining safe and reliable network operations due to the complexity and uncertainties in active distribution networks, e.g., congestion and reliability problems. Effective congestion management (CM) policies require appropriate indices to quantify the seriousness and customer contributions to congested areas. Developing an accurate model to identify the residual life of aged equipment is also essential in long-term CM procedures. The assessment of network reliability and equipment end-of-life failure also plays a critical role in network planning and regulation. The main contributions of this thesis include a) outlining the specific characteristics of congestion events and introducing the typical metrics to assess the effectiveness of CM approaches; b) proposing spatial, temporal and aggregate indices for rapidly recognizing the seriousness of congestion in terms of thermal and voltage violations, and proposing indices for quantifying the customer contributions to congested areas; c) proposing an improved method to estimate the end-of-life failure probabilities of transformers and cables lines taking real-time relative aging speed and loss-of-life into consideration; d) quantifying the impact of different levels of EV penetration on the network reliability considering end-of-life failure on equipment and post-fault network reconfiguration; and e) proposing an EV smart charging optimization model to improve network reliability and reduce the cost of customers and power utilities. Simulation results illustrate the feasibility of the proposed indices in rapidly recognizing the congestion level, geographic location, and customer contributions in balanced and unbalanced systems. Voltage congestion can be significantly relieved by network reconfiguration and the utilization of the proposed indices by utility operators in CM procedures is also explained. The numerical studies also verify that the improved Arrhenius-Weibull can better indicate the aging process and demonstrate the superior accuracy of the proposed method in identifying residual lives and end-of-life failure probabilities of transformers and conductors. The integration of EV has a great impact on equipment aging failure probability and loss-of-life, thus resulting in lower network reliability and higher cost for managing aging failure. Finally, the proposed piecewise linear optimization model of the EV smart charging framework can significantly improve network reliability by 90% and reduce the total cost by 83.8% for customers and power utilities

Decision Support for Smart Grid Planning and Operation Considering Reliability

[ES] Esta tesis aporta contribuciones a los temas de los sistemas de energía y la movilidad eléctrica. Por lo tanto, se proponen soluciones innovadoras para la planificación de la red de distribución radial tradicional sin o con pocas unidades de recursos energéticos distribuidos, y para la planificación, operación, reconfiguración, y gestión de recursos energéticos en redes de distribución en media tensión considerando una alta penetración de los recursos energéticos distribuidos en el contexto de las redes inteligentes. Las preocupaciones sobre la disponibilidad de combustibles fósiles y el aumento de los efectos climático causados por su uso generalizado en la generación de electricidad han llevado a varias políticas e incentivos para atenuar estos problemas. Estas medidas contribuyeron a inversiones considerables en fuentes de energía renovables y motivaron muchas iniciativas de redes inteligentes. Aunque el panorama futuro de los sistemas eléctricos modernos parece muy prometedor, la integración a gran escala de fuentes de energía renovables de naturaleza intermitente, como la eólica y la fotovoltaica, plantea nuevos desafíos y limitaciones en la industria eléctrica actual. Hoy en día, el diseño de la red de distribución no está correctamente preparado para alojar una gran cantidad de fuentes de energía renovables distribuidas. Por lo tanto, los operadores del sistema de distribución reconocen la necesidad de cambiar el diseño de la red mediante la planificación y el refuerzo. A medida que aumenta la penetración de las fuentes de energía renovable, un agregador de energía puede proporcionar una generación y demanda altamente flexibles según lo requiere el paradigma de red inteligente. Además, esta entidad puede permitir lograr una alta integración de la oferta de energía renovable y aumentar el valor para los pequeños productores y consumidores que no pueden negociar directamente en el mercado mayorista. Sin embargo, la entidad agregadora de energía necesita herramientas adecuadas de apoyo a la decisión para superar los desafíos complejos y hacer frente a un gran número de recursos energéticos. Por lo tanto, la gestión de recursos energéticos es crucial para que la entidad agregadora de energía reduzca los costos de operación, aumente de los beneficios, reduzca la huella de carbono y mejore la estabilidad del sistema. En la perspectiva mundial actual, muchas personas se están mudando a las ciudades en busca de una mejor calidad de vida, contribuyendo de esta manera a la continua expansión de las áreas urbanas. En consecuencia, el sector de transportes está jugando un papel crítico en las emisiones de dióxido de carbono. Teniendo en cuenta esto, muchas ventajas medioambientales y económicas pueden ser obtenidas del cambio de los motores de combustión interna a los vehículos eléctricos. Sin embargo, este cambio contribuirá a una carga en la red de distribución, dando lugar a la posibilidad de congestión de la red. Por lo tanto, para facilitar la integración de la carga de los vehículos eléctricos en la red de distribución, un modelo de predicción del comportamiento del usuario de un vehículo eléctrico pode ser una herramienta muy importante. Además, el paradigma de la red inteligente está desafiando la estructura de control y operación convencional diseñado para redes de distribución pasivas. De este modo, la reconfiguración de la red de distribución será una estrategia esencial y significativa para el operador del sistema de distribución. En el estado del arte actual se identificó una falta de modelos, estrategias y herramientas de apoyo a la toma de decisiones adecuadas para los dominios de problemas de planificación, operación y gestión de recursos energéticos de redes de distribución en media tensión con una alta penetración de fuentes de energía distribuidas. Por lo tanto, surgen varios desafíos de investigación que llevan a la necesidad de desarrollar modelos nuevos e innovadores que aborden: a) el impacto de las fuentes de energía renovable y la variabilidad de la demanda en la planificación de la expansión a largo plazo, b) el problema de la gestión de los recursos energéticos a gran escala, teniendo en cuenta la demanda, las fuentes de energía renovables, los vehículos eléctricos y la variabilidad de los precios del mercado, c) el análisis de impacto de los precios de carga dinámicos de los vehículos eléctricos en la operación de la red de distribución y en el comportamiento del usuario del vehículo eléctrico. Además, en el contexto de la red de distribución de media tensión radial tradicional, también se verificó la necesidad de modelos innovadores para mejorar la confiabilidad a través de la identificación de nuevas inversiones en los componentes de la red. Por lo tanto, esta tesis propone soluciones innovadoras para hacer frente a todos estos vacíos y problemas. Para ese propósito, las contribuciones de la tesis, resultan en un innovador sistema de apoyo a la decisión llamado Advanced Decision Support Tool for Smart Grid Planning and Operation (SupporGrid). El SupporGrid se compone de un conjunto de modelos diversificados que juntos contribuyen a manejar la complejidad de la planificación tradicional de las redes de distribución radial (PlanTGrid), y para la planificación (PlanSGrid), operación (OperSGrid), y los problemas de gestión de recursos energéticos (ERMGrid) en redes de distribución de media tensión en el paradigma de red inteligente. PlanTGrid incluye un modelo de planificación de expansión para redes de distribución radial tradicionales para identificar la posibilidad de nuevas inversiones al costo mínimo. La planificación de la expansión a largo plazo de las redes de distribución en un contexto de red inteligente con una alta penetración de fuentes de energía renovables distribuidas y que trata las fuentes de incertidumbre se resuelve mediante el uso PlanSGrid. OperSGrid contiene una herramienta de simulación de viajes de los usuarios de los vehículos eléctricos funcionando en conjunto con un modelo de operación y reconfiguración que utiliza descomposición de Benders y precios marginales para comprender el impacto del precio de carga de energía dinámica en ambos lados: la red de distribución y el usuario de vehículo eléctrico. Para hacer frente a la gestión de recursos energéticos a gran escala con problemas de respuesta a la demanda y sistemas de almacenamiento de energía, así como con la variabilidad de la demanda, las fuentes de energía renovable, los vehículos eléctricos y el precio de mercado, ERMGrid incluye un modelo estocástico de dos etapas. Las metodologías desarrolladas para el sistema de soporte de decisiones se han probado y validado en escenarios realistas. Los resultados prometedores logrados en condiciones realistas respaldan la hipótesis de que las metodologías son adecuadas e innovadoras para la planificación de la red de distribución radial tradicional, y para la planificación, operación, reconfiguración y gestión de recursos energéticos a largo plazo de la red de distribución considerando alta penetración de recursos energéticos distribuidos y de vehículos eléctricos en el contexto de red inteligente. Los resultados prometedores logrados en condiciones realistas respaldan la hipótesis de que las metodologías son adecuadas e innovadoras para la planificación de la red de distribución radial tradicional, y para la planificación, operación, reconfiguración y gestión de recursos energéticos a largo plazo de la red de distribución considerando la alta distribución de recursos energéticos y la penetración de vehículos eléctricos. De hecho, este sistema de apoyo a la decisión mejorará el funcionamiento de las redes de distribución de media tensión, permitiendo ahorros para las partes interesadas

A review of optimal planning active distribution system:Models, methods, and future researches

Due to the widespread deployment of distributed energy resources (DERs) and the liberalization of electricity market, traditional distribution networks are undergoing a transition to active distribution systems (ADSs), and the traditional deterministic planning methods have become unsuitable under the high penetration of DERs. Aiming to develop appropriate models and methodologies for the planning of ADSs, the key features of ADS planning problem are analyzed from the different perspectives, such as the allocation of DGs and ESS, coupling of operation and planning, and high-level uncertainties. Based on these analyses, this comprehensive literature review summarizes the latest research and development associated with ADS planning. The planning models and methods proposed in these research works are analyzed and categorized from different perspectives including objectives, decision variables, constraint conditions, and solving algorithms. The key theoretical issues and challenges of ADS planning are extracted and discussed. Meanwhile, emphasis is also given to the suitable suggestions to deal with these abovementioned issues based on the available literature and comparisons between them. Finally, several important research prospects are recommended for further research in ADS planning field, such as planning with multiple micro-grids (MGs), collaborative planning between ADSs and information communication system (ICS), and planning from different perspectives of multi-stakeholders

Mitigating unbalance using distributed network reconfiguration techniques in distributed power generation grids with services for electric vehicles: A review

© 2019 Elsevier Ltd With rapid movement to combat climate change by reducing greenhouse gases, there is an increasing trend to use more electric vehicles (EVs) and renewable energy sources (RES). With more EVs integration into electricity grid, this raises many challenges for the distribution service operators (DSOs) to integrate such RES-based, distributed generation (DG) and EV-like distributed loads into distribution grids. Effective management of distribution network imbalance is one of the challenges. The distribution network reconfiguration (DNR) techniques are promising to address the issue of imbalance along with other techniques such as the optimal distributed generation placement and allocation (OPDGA) method. This paper presents a systematic and thorough review of DNR techniques for mitigating unbalance of distribution networks, based on papers published in peer-reviewed journals in the last three decades. It puts more focus on how the DNR techniques have been used to manage network imbalance due to distributed loads and DG units. To the best of our knowledge, this is the first attempt to review the research works in the field using DNR techniques to mitigate unbalanced distribution networks. Therefore, this paper will serve as a prime source of the guidance for mitigating network imbalance using the DNR techniques to the new researchers in this field

Review of trends and targets of complex systems for power system optimization

Optimization systems (OSs) allow operators of electrical power systems (PS) to optimally operate PSs and to also create optimal PS development plans. The inclusion of OSs in the PS is a big trend nowadays, and the demand for PS optimization tools and PS-OSs experts is growing. The aim of this review is to define the current dynamics and trends in PS optimization research and to present several papers that clearly and comprehensively describe PS OSs with characteristics corresponding to the identified current main trends in this research area. The current dynamics and trends of the research area were defined on the basis of the results of an analysis of the database of 255 PS-OS-presenting papers published from December 2015 to July 2019. Eleven main characteristics of the current PS OSs were identified. The results of the statistical analyses give four characteristics of PS OSs which are currently the most frequently presented in research papers: OSs for minimizing the price of electricity/OSs reducing PS operation costs, OSs for optimizing the operation of renewable energy sources, OSs for regulating the power consumption during the optimization process, and OSs for regulating the energy storage systems operation during the optimization process. Finally, individual identified characteristics of the current PS OSs are briefly described. In the analysis, all PS OSs presented in the observed time period were analyzed regardless of the part of the PS for which the operation was optimized by the PS OS, the voltage level of the optimized PS part, or the optimization goal of the PS OS.Web of Science135art. no. 107

Impact of distributed generation on protection and voltage regulation of distribution systems : a review

During recent decades with the power system restructuring process, centralized energy sources are being replaced with decentralized ones. This phenomenon has resulted in a novel concept in electric power systems, particularly in distribution systems, known as Distributed Generation (DG). On one hand, utilizing DG is important for secure power generation and reducing power losses. On the other hand, widespread use of such technologies introduces new challenges to power systems such as their optimal location, protection devices' settings, voltage regulation, and Power Quality (PQ) issues. Another key point which needs to be considered relates to specific DG technologies based on Renewable Energy Sources (RESs), such as wind and solar, due to their uncertain power generation. In this regard, this paper provides a comprehensive review of different types of DG and investigates the newly emerging challenges arising in the presence of DG in electrical grids.fi=vertaisarvioitu|en=peerReviewed

A comprehensive review of renewables and electric vehicles hosting capacity in active distribution networks

© Copyright 2023 The Author(s). The excessive integration of renewable distributed generation (RDG) and electric vehicles (EVs) could be considered the two most problematic elements representing the greatest threat to the distribution network (DN) technical operation. In order to avoid going beyond technical limitations, the term hosting capacity (HC) was proposed to define the highest permitted amount of distributed generation (DG) or EVs that can be integrated safely into the DN. The connection of RDGs was first brought to the attention of researchers and DN operators since it accounts for the most notable portion of these technical issues. Hence, the phrase ‘DG-HC’ was initially proposed and evolved significantly over the last few years. Currently, EV integration in most DNs worldwide is still low, but given the worldwide support for clean transportation options, expectations are raised for a significant increase. As a result, it is anticipated that over the next years, the effect of EV integration on the DN will be highly noticeable, requiring greater attention from researchers and DN operators to define the accepted limits of EV penetration levels, ‘EV-HC,’ which is expected to pass along the same line of DG-HC. This article provides an in-depth review of both DG-HC and EV-HC. It first analyses how the DG-HC research has grown over the years and then studies the published EV-HC papers, illustrating to what extent there is a similarity between them and, finally, employs these analyses to expect future development in the EV-HC research area. This article includes the different uses of the term HC, the most common performance indices of DG-HC, the various methods for assessing DG-HC, the different techniques for DG-HC enhancement, the effects of integrating EVs on the DG-HC, and finally, calculating and enhancing methods for EV-HC

A review on economic and technical operation of active distribution systems

© 2019 Elsevier Ltd Along with the advent of restructuring in power systems, considerable integration of renewable energy resources has motivated the transition of traditional distribution networks (DNs) toward new active ones. In the meanwhile, rapid technology advances have provided great potentials for future bulk utilization of generation units as well as the energy storage (ES) systems in the distribution section. This paper aims to present a comprehensive review of recent advancements in the operation of active distribution systems (ADSs) from the viewpoint of operational time-hierarchy. To be more specific, this time-hierarchy consists of two stages, and at the first stage of this time-hierarchy, four major economic factors, by which the operation of traditional passive DNs is evolved to new active DNs, are described. Then the second stage of the time-hierarchy refers to technical management and power quality correction of ADSs in terms of static, dynamic and transient periods. In the end, some required modeling and control developments for the optimal operation of ADSs are discussed. As opposed to previous review papers, potential applications of devices in the ADS are investigated considering their operational time-intervals. Since some of the compensating devices, storage units and generating sources may have different applications regarding the time scale of their utilization, this paper considers real scenario system operations in which components of the network are firstly scheduled for the specified period ahead; then their deviations of operating status from reference points are modified during three time-intervals covering static, dynamic and transient periods