Abstract
The development of the smart grid concept implies major changes in the operation and planning of distribution systems, particularly in Low Voltage (LV) networks. The majority of small-scale Distributed Energy Resources (DER)-microgeneration units, energy storage devices, and flexible loads-are connected to LV networks, requiring local control solutions to mitigate technical problems resulting from its integration in the system. Simultaneously, LV connected DER can be aggregated in small cells in order to globally provide new functionalities to system operators. Within this view, the Microgrid (MG) concept has been pointed out as a solution to extend and decentralize the distribution network monitoring and control capability. An MG is a highly flexible, active, and controllable LV cell, incorporating microgeneration units based on Renewable Energy Sources (RES) or low carbon technologies for small-scale combined heat and power applications, energy storage devices, and loads. The coordination of MG local resources, achieved through an appropriated network of controllers and communication system, endows the LV system with sufficient autonomy to operate interconnected to the upstream network or autonomously-emergency operation. In this case, the potentialities of DER can be truly realized if the islanded operation is allowed and bottom-up black start functionalities are implemented. To achieve this operational capability, this chapter presents the control procedures to be used in such a system to deal with the islanded operation and to exploit the local generation resources as a way to help in power system restoration in case of an emergency situation. A sequence of actions for a black start procedure is identified, and it is expected to be an advantage for power system operation regarding reliability as a result from the presence of a huge amount of dispersed generation.

Abstract
A microgrid embraces a low-voltage (LV) distribution grid with distributed energy resources (DER) and controllable loads. In the last years, there has been a growing awareness in exploiting microgrids to facilitate DER integration in electric power systems as well as to improve reliability and power quality in distribution grids. A microgrid can operate connected to the upstream medium voltage (MV) grid-utility grid-or islanded (disconnected from the MV grid) in a controlled and coordinated way. A major challenge associated with the implementation of microgrids is to design a suitable protection system scheme for different operating conditions. To overcome this challenge, different approaches have been proposed in the literature. The protection systems applied at microgrids must work both in utility grid faults and microgrid faults. Faults on the utility grid could lead to a protection response that isolates the microgrid from the utility grid as fast as required to keep the microgrid safety. On the other hand, faults in the own microgrid require the smallest sector removal of the microgrid to isolate the fault. Due to the presence of several DER in microgrids, the protection systems are also needed to cope with the bidirectional energy flows. Thus, the traditional protection devices (fuses and electromechanical switches) and standard solid-state relays are designed for selectivity purposes, making them inapt to ensure the protection of microgrids. These protection devices do not provide flexibility for setting the tripping characteristics neither the current direction sensitivity feature. Some problems related to protections sensitivity and selectivity arises when a microgrid is in islanded operation (DER generation). Thus, this new paradigm of distribution facilities requires a protection system based on microprocessor relaying and communications. Protecting microgrids in both modes (grid-connected and islanded) can be achieved by using different communication architectures associated with protections. Using centralized or distributed architectures means that the relay protection settings are modified centrally or locally regarding microgrid operating conditions. This chapter aims to provide the key highlights of the available protection schemes used to address microgrid protection issues.

Abstract
Over the last few years, the need for electricity has increased in households as new and different appliances are progressively introduced. This increased demand for electricity raises a concern to many developed and developing countries since it is a human's responsibility to assure a sustainable future. Energy demand management can be an effective approach to reduce the energy consumption; this approach requires final consumers to be empowered with more information for improving their decision-making and actions on the energy usage through increased awareness. Therefore, metering and behind the meter monitoring systems have a crucial role in the exploitation of this potential in the customer side. A significant disadvantage of traditional meters is the fact that they do not provide detailed information to the customers, which is achieved with the help of smart meters. A smart meter allows the customers to have access to the information about electricity consumption of the appliances in their houses. The acceptance of smart meters by customers is the fundamental step to achieve the potential carbon emission reductions that are provided by the use of advanced metering infrastructures. The smart meter is an advanced energy meter that measures consumption of electrical energy such as a traditional meter but also provides additional information in real time, making it the key element of the new energy demand management system. Integration of smart meters into electricity grids implies the implementation of several technologies, depending on the features that each situation request. The design of a smart meter has been in constant development since it is increasingly necessary to satisfy both the requirements of the utility company and those of the customer. Therefore, smart metering provides benefits to the energy utilities optimizing their business, and beyond that it can provide advantages to the final customers. All over the world many smart metering projects have been developed. However, it is still not entirely clear which are the associated costs, the characteristics, and the mechanisms internal to projects that bring advantages and benefits for the different concerned parties. The smart metering methods and the communication technologies used in smart grid are being substantially studied due to widespread applications of smart grid. The monitoring and control processes are largely used in industrial systems. Nevertheless, the energy management requirements at service supplier and customer promoted the evolution of smart grid and consequently the development of microgrids. This chapter discusses various characteristics and technologies that can be integrated with a smart meter for smart grids and microgrids uses. In fact, placement of smart meters needs proper selection and implementation of a communication network fulfilling the security standards of smart grid/microgrid communication. This chapter outlines various issues and challenges involved in design, deployment, utilization, and maintenance of the smart metering infrastructure.

Abstract
In this work, the evaluation of the performance of a small-size photovoltaic plant, with 15 kWp of capacity, is made and some proposals for its optimization are presented. The plant consists of a grid-connected centralized system, where the output power is consumed in the same building. The PV plant production data of the last couple of years are analysed, filtering the periods of inoperation. To obtain an accurate prediction of the efficiency and power output, the characteristics of all plant components were introduced in SAM software. The results obtained through the simulations and the measured output power values were compared. (C) 2018 The Authors. Published by Elsevier Ltd.

Abstract
The content of this paper aims to assist in the development and implementation of microgrids by addressing the challenges and possible solutions for their protection systems. Therefore, an overview of some protection methods available in the literature that can be implemented to ensure a safe and reliable microgrid operation is presented, including the most common protection devices and earthing schemes that can be adopted in low voltage distribution systems. In addition, this paper also presents a brief fault analysis of internal faults at three different locations in an industrial microgrid with centralized and decentralized deployment of energy sources, as well as a short-circuit analysis of symmetric and asymmetric faults at these faulty locations. An approximate method based on the calculation of the equivalent impedance seen from the fault location is used to determine the fault currents. This study is made to observe how microgrids with different configurations perform in the event of internal faults. It is demonstrated in this work that setting a specific protection strategy to allow the microgrid to operate effectively during both operation modes can be problematic and expensive in most situations. With this in mind, additional effort is necessary to engineer and implement new protection approaches that can overcome the limitations of protection systems in future microgrids.

Abstract
Further integration of distributed renewable energy sources in distribution systems requires a paradigm change in grid management by the distribution system operators (DSOs). DSOs are currently moving to an operational planning approach based on activating flexibility from distributed energy resources in day/hour-ahead stages. This paper follows the DSO trends by proposing a methodology for active grid management by which robust optimization is applied to accommodate spatial-temporal uncertainty. The proposed method entails the use of a multi-period AC-OPF, ensuring a reliable solution for the DSO. Wind and PV uncertainty is modeled based on spatial-temporal trajectories, while a convex hull technique to define uncertainty sets for the model is used. A case study based on real generation data allows illustration and discussion of the properties of the model. An important conclusion is that the method allows the DSO to increase system reliability in the real-time operation. However, the computational effort grows with increases in system robustness.