Ancillary Services in Hybrid AC/DC Low Voltage Distribution Networks

In the last decade, distribution systems are experiencing a drastic transformation with the advent of new technologies. In fact, distribution networks are no longer passive systems, considering the current integration rates of new agents such as distributed generation, electrical vehicles and energy storage, which are greatly influencing the way these systems are operated. In addition, the intrinsic DC nature of these components, interfaced to the AC system through power electronics converters, is unlocking the possibility for new distribution topologies based on AC/DC networks. This paper analyzes the evolution of AC distribution systems, the advantages of AC/DC hybrid arrangements and the active role that the new distributed agents may play in the upcoming decarbonized paradigm by providing different ancillary services.Ministerio de Economía y Competitividad ENE2017-84813-RUnión Europea (Programa Horizonte 2020) 76409

Microgrids & District Energy: Pathways To Sustainable Urban Development

A microgrid is an energy system specifically designed to meet some of the energy needs of a group of buildings, a campus, or an entire community. It can include local facilities that generate electricity, heating, and/or cooling; store energy; distribute the energy generated; and manage energy consumption intelligently and in real time. Microgrids enable economies of scale that facilitate local production of energy in ways that can advance cost reduction, sustainability, economic development, and resilience goals. As they often involve multiple stakeholders, and may encompass numerous distinct property boundaries, municipal involvement is often a key factor for successful implementation. This report provides an introduction to microgrid concepts, identifies the benefits and most common road blocks to implementation, and discusses proactive steps municipalities can take to advance economically viable and environmentally superior microgrids. It also offers advocacy suggestions for municipal leaders and officials to pursue at the state and regional level. The contents are targeted to municipal government staff but anyone looking for introductory material on microgrids should find it useful

Challenges to the Integration of Renewable Resources at High System Penetration

Successfully integrating renewable resources into the electric grid at penetration levels to meet a 33 percent Renewables Portfolio Standard for California presents diverse technical and organizational challenges. This report characterizes these challenges by coordinating problems in time and space, balancing electric power on a range of scales from microseconds to decades and from individual homes to hundreds of miles. Crucial research needs were identified related to grid operation, standards and procedures, system design and analysis, and incentives, and public engagement in each scale of analysis. Performing this coordination on more refined scales of time and space independent of any particular technology, is defined as a “smart grid.” “Smart” coordination of the grid should mitigate technical difficulties associated with intermittent and distributed generation, support grid stability and reliability, and maximize benefits to California ratepayers by using the most economic technologies, design and operating approaches

A review of microgrid development in the United States – A decade of progress on policies, demonstrations, controls, and software tools

Microgrids have become increasingly popular in the United States. Supported by favorable federal and local policies, microgrid projects can provide greater energy stability and resilience within a project site or community. This paper reviews major federal, state, and utility-level policies driving microgrid development in the United States. Representative U.S. demonstration projects are selected and their technical characteristics and non-technical features are introduced. The paper discusses trends in the technology development of microgrid systems as well as microgrid control methods and interactions within the electricity market. Software tools for microgrid design, planning, and performance analysis are illustrated with each tool's core capability. Finally, the paper summarizes the successes and lessons learned during the recent expansion of the U.S. microgrid industry that may serve as a reference for other countries developing their own microgrid industries

Technical and economic feasibility of a microgrid for a fire station in Humboldt County, California.

Microgrids are emerging as a promising solution to unreliable grid energy. Today, California is not only witnessing grid resiliency challenges from natural disasters such as wildfires, earthquakes, floods and heatwaves, but it is also seeking to green the grid and bring more renewables online. For example, Humboldt County, where this project is focused, has recently experienced an earthquake of 6.4M (on December 22nd, 2022), which shut down the regional grid for ~20 hours. Microgrid adoption enables critical facilities to operate seamlessly. The Humboldt Bay Fire Station (HBFS) No.1 is one such example, where first responders work to protect citizens against emergencies, be it emergency medical services (EMS) operations or fire rescue or even helping in restoration of power lines. This study involves a techno-economic analysis of a microgrid design that could support efficient and seamless operations for the fire station as it serves the people of Humboldt County during emergencies. A clean energy microgrid for the station aligns with the Humboldt County GHG emission target to reach net zero by 2030, and could provide resilient power to their general and critical loads during regular operations and emergencies. The recommended microgrid for the HBFS No. 1 facility includes a 70-kW photovoltaic (PV) array and a 90 kW/360 kWh battery energy storage system (BESS). The project cost ranges from $300k to$600k (depending upon the level of investment tax credits (ITC) the microgrid project would get). It provides 51-day resiliency in the best case and 28-hour resiliency in the worst case depending upon the weather condition. The system would also reduce greenhouse gas emissions from electricity use at the station by over 98% annually. Considering the potential availability of incentives and the value of resiliency (VoR), the microgrid project for HBFS No.1 demonstrates promising economic feasibility results. The next steps involve further evaluation of the project\u27s financial viability, engaging with relevant stakeholders to secure funding, and proceeding with the detailed design and implementation phases of the microgrid

Electric Power Conversion and Micro-Grids

This edited volume is a collection of reviewed and relevant research chapters offering a comprehensive overview of recent achievements in the field of micro-grids and electric power conversion. The book comprises single chapters authored by various researchers and is edited by a group of experts in such research areas. All chapters are complete in themselves but united under a common research study topic. This publication aims at providing a thorough overview of the latest research efforts by international authors on electric power conversion, micro-grids, and their up-to-the-minute technological advances and opens new possible research paths for further novel developments

Effects of energy storage systems grid code requirements on interface protection performances in low voltage networks

The ever-growing penetration of local generation in distribution networks and the large diffusion of energy storage systems (ESSs) foreseen in the near future are bound to affect the effectiveness of interface protection systems (IPSs), with negative impact on the safety of medium voltage (MV) and low voltage (LV) systems. With the scope of preserving the main network stability, international and national grid connection codes have been updated recently. Consequently, distributed generators (DGs) and storage units are increasingly called to provide stabilizing functions according to local voltage and frequency. This can be achieved by suitably controlling the electronic power converters interfacing small-scale generators and storage units to the network. The paper focuses on the regulating functions required to storage units by grid codes currently in force in the European area. Indeed, even if such regulating actions would enable local units in participating to network stability under normal steady-state operating conditions, it is shown through dynamic simulations that they may increase the risk of unintentional islanding occurrence. This means that dangerous operating conditions may arise in LV networks in case dispersed generators and storage systems are present, even if all the end-users are compliant with currently applied connection standards

Utilization of renewable energy sources in microgrids

Využití solární energie je jednou z nejoblíbenějších technologií výroby energie mezi několika typy obnovitelných zdrojů energie. Dva obnovitelné zdroje energie, které jsou v současných mikrosítích využívány, jsou v této práci teoreticky diskutovány. Dále je názorně předveden dopad obnovitelných zdrojů energie na mikrosítě a struktura mikrosítí. Součástí této práce je rovněž komplexní simulační analýza distribuční soustavy středního (22 kV) a nízkého napětí (400 V) provedená pomocí softwaru eVlivy před a po připojení PVPPs do distribuční soustavy Středočeského kraje. Analýza zatížení soustavy a napěťový profil v každém uzlu distribuční soustavy středního a nízkého napětí jsou zobrazeny graficky.Solar Power utilization is the one of the most popular power production technology among the several types of renewable energy sources. There are two types of renewable energy sources like solar energy and wind energy utilization in Microgrid structure has been described theoretically. Impact of renewable energy sources on Microgrid and structure of Microgrid has been presented in detail. This master thesis presents a comprehensive simulation analysis of medium voltage distribution line 22kV and low voltage line (400 V) with the help simulation software eVlivy before and after connection of PVPPs into the distribution system in Central Bohemian Region. The load flow analysis and voltage profile at each node of medium and low voltage distribution system has been characterized graphically