Abstract
One of the main constraints for Renewable Energy Sources (RES) integration in LV networks are overvoltages caused by changing the normal power flow of the network. In favourable weather conditions high voltages may lead to overvoltage trips thus preventing the injection of renewable energy into the grid. An optimized management of power injection from controlled RES to keep the grid voltage within regulatory limits enables a larger energy output and deployment of distributed generation. The SuSTAINABLE project developed a centralized algorithm based on a hierarchical methodology to control distributed power injection and solve the identified issue. A decentralized algorithm based on a coordinated droop control embedded in the inverters was developed as well. In order to evaluate the proposed algorithms a controllable PV µG and batteries were installed at the end of the feeder of a real LV network operated by EDP Distribuicao. The obtained results are presented in this paper and show that a hierarchical methodology to control power injection could optimize RES energy production while maintaining voltages within bounds, thus enabling a larger deployment of RES at the LV levels.

Abstract
In order to improve their competitive performance, airline companies often adopt as a strategy to establish arrangement between two or more organizations agreeing to cooperate on a substantial level. This strategy is often known as airline alliances. A paradigm to analyze the collective intelligence behavior which emerges from a group, as a strategic alliance, is the flocking behavior. Inspired by the Cucker and Smale algorithm (C-S) we propose a new version of the flocking behavior algorithm applied to airline alliances. Our goal is to understand the link between strategic alliances and flocks. For this new approach, metrics were obtained for the parameters of C-S algorithm, namely position, velocity and influence, where the latter uses cooperative games. Besides, reinforcement learning mechanisms have been explored. Some relevant outputs for airline alliances as the permanence rate and the growth rate were computed for each of the five configurations in analysis.

Abstract

Abstract
The constant growth of wind farms in the Brazilian electric system increases the concerns regarding power quality, especially related to harmonic distortions. At the same time, wind generation also becomes relevant in the context of power system stability, operating as ancillary services. One of the requirements of the system operator is the injection of reactive power by the wind farms to maintain the voltage levels. Considering that the actual studies only considers the operation of the wind generators with unitary power factor, the present work aims to evaluate the harmonic impact of Wind farms operating with reactive power injection on the electric system buses. For this purpose two monitoring campaigns in a wind farm of the CPFL Renováveis were performed with different power factors operating modes in the wind generators. These results were utilized in computational studies to evaluate the impact in voltage distortion at the PCC. The results obtained in this work demonstrated a significant impact on the harmonic current generation and in the voltage harmonic distortion due to the reactive power injection by the wind generators of the wind farm.

Abstract

Abstract
Developing an inverter with high efficiency and with the ability of starting with inductive, capacitive, and resistive loads along with output voltage stability is a challenging problem. Considering higher reliability and convenient maintenance, this paper focuses on the use of analog circuits. In this regard, this paper uses pulse width modulation techniques, intelligent feedback, and peak as well as effective voltage supply are employed. Results indicated that this designed inverter with a power of 700 W can be started with ohmic loads (100% quality), inductive loads (97% quality), and capacitive loads (83% quality).