The unpredictability and intermittency introduced byRenewable Energy Sources (RESs) in power systems may lead to unforeseen peaks of energy production, which might differ from energy demand. To manage these mismatches, a proper communication between prosumers (i.e., users with RESs that can either inject or absorb energy) and active users (i.e., users that agree to have their loads changed according to the system needs) is required.To achieve this goal, the centralized approach used in traditional power systems is no longer possible because both prosumers and active users would like to take part in energy transactions, and a decentralized approach based on transactive energy systems (TESs) and Peer-to-Peer (P2P) energy transactions should be adopted. In this context, theDistributed Ledger Technology (DLT), based on the blockchain concept arises as the most promising solution to enable smart contracts between prosumers and active users, which are safely guarded in blocks with cryptographic hashes. The aim of this paper is to provide a review about the deployment of decentralized TESs and to propose and discuss a transactive management infrastructure. In this context, the concept of Proof of Energy is proposed as a novel consensus protocol for P2P energy exchanges managed by DLT. An application of the proposed infrastructure considering a Virtual Power Plant (VPP) aggregator and residential prosumers endowed with a new transactive controller to manage the electrical storage system is discussed. Q1

The aim of this work is to analyze a typical configuration of a Wind Turbine Generator System (WTGS) equipped with a Variable Speed Generator. Nowadays, doublyfed induction generators are being widely used on WTGS, although synchronous generators are being extensively utilized too. There are different types of synchronous generators, but the multi-pole Permanent Magnet Synchronous Generator (PMSG) is chosen in order to obtain its model. It offers better performance due to higher efficiency and less maintenance since it does not have rotor current and can be used without a gearbox, which also implies a reduction of the weight of the nacelle and a reduction of costs. Apart from the generator, the analyzed WTGS consists of another three parts: wind speed, wind turbine and drive train. These elements have been modeled and the equations that explain their behavior have been introduced. What is more, the whole WTGS has been implemented in MATLAB/Simulink interface. Moreover, the concept of the Maximum Power Point Tracking (MPPT) has been presented in terms of the adjustment of the generator rotor speed according to instantaneous wind speed.

Abstract-This work analyzes the behavior of an MMC-HVDC-connected off-shore wind power plant (WPP) during dc faults. For that purpose, detailed models of the dc cable, MMC stations and transformers have been used in order to obtain reliable results. The influence of the WPP control method in the short-circuit behavior of the HVDC link has also been studied. Results show that the dynamics of the WPP contribution to pole-to-ground faults are slightly slower than those of the wind turbines current control loops. Therefore, the wind turbine front end converters can be used to reduce the peak and average value of the fault current in such a system. Moreover, it has been found that ferro-resonant oscillations can appear in the off-shore ac-grid when the WPP delivers constant power during faults.

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Cold ironing, which is the procedure of supplying Q1 4 shoreside electrical power to a ship at berth when its engines are 5 turned OFF, arises as the eco-friendly way to deliver power to ships 6 while they are berthed in ports, thus avoiding the use of diesel 7 engines onboard, which provokes the emission of large amounts 8 of greenhouse gases into the atmosphere. The aim of this study is 9 twofold. First, a survey of research developments on cold ironing 10 is carried out in order to show the state-of-the-art on the problem 11 of greenhouse gases emitted by ships while docked and how to 12 tackle it. Current regulations and examples of current ports that 13 make use of technologies for cold ironing purposes are also shown. 14 Second, the study proposes the use of a cold ironing system in the 15 port of Barcelona, where the power generation is entirely given by 16 renewable energy systems (wind turbines and photovoltaic panels).