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The fault current of generation with renewable energy sources that use inverters (FERUI) between the grid and generation, is limited due to limitations of the electronic components, so a dispute arises related to the viability of the overcurrent relay in FERUI applications. These disputes arise due to the unavailability of FERUI fault current characteristics. The problem is further complicated by the numerous fault current controls, where various current characteristics can be obtained. This document aims to establish the various fault current characteristics of FERUI, meeting the requirements of the Brazilian grid code. From these characteristics, disputes related to the feasibility of overcurrent relays for FERUI applications can be resolved and the appropriate types of control that allow satisfactory performance can be identified. [ABSTRACT FROM AUTHOR]

Unbalanced voltage drops can lead to non-sinusoidal current injections and power oscillations at twice the fundamental frequency of the grid in photovoltaic parks connected to the electrical system. These oscillations can damage the inverter DC link capacitor, which is one of the components that most limits the life of the inverter. Proper controls of these converters can address this problem efficiently. In those solutions, the reference current calculation is one of the most important problems to be addressed for reliable operation of converters under unbalanced grid faults. This article presents a comparison of the reference current generation schemes, during a single-phase fault in the network..It provides an evaluation of the performance of different techniques and being able to help in the selection of the appropriate control during major network failures. [ABSTRACT FROM AUTHOR]

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Stream processing platforms allow processing and analyzing realtime data. A recognized system for this purpose is the so-called Storm platform, an open-source system for distributed computing, which is a scalable, fast and, fault-tolerant. The Storm platform may be deployed on a large number of processors. However, determining the proper number of processors that are suitable to execute a given Storm based software application is a challenging task, especially if the application is intended to serve a very large user community. One way of solving this is by employing a simulation model that allows the evaluation of its performance under different workload scenarios. In this paper, a simulation model of a Storm application using the DEVS formalism is presented, then, an equivalent model is described using Timed Automata (TA). Throughout a procedure called "Bisimulation", it is checked that both models are effectively equivalent. Finally, the model defined using TA is formally verified evaluating its properties, proving that the simulation model has the same behavior as the real applications. [ABSTRACT FROM AUTHOR]