Improvements in frequency control of an AC microgrid by means of micro-hydropower combined flow-reduced dump load control method

Load Frequency Control (LFC) is an issue of top importance to ensure microgrids (MGs) safe and reliable operation in AC MGs. Primary frequency control of each energy source can be guaranteed in AC MGs in order to integrate other energy sources. This paper proposes a micro-hydro frequency control scheme, combining the control of a reduced dump load and the nozzle flow control of Pelton turbines operating in isolated from electricity grid. Some researchs have reported the integration of dump load and flow control methods, but they did not reduce the dump load value and adjust the nozzle flow linearly to the power value demanded by users, causing the inefficient use of water. Simulation results were obtained in Matlab®/Simulink® using models obtained from previous research and proven by means of experimental studies. The simulation of the proposed scheme shows that instantaneous frequency variation is about 2 % even for perturbations magnitude up to 12 %. The validation result shows a 60 % reduction in overshoot and settling time of frequency temporal behaviour operating the micro-hydro autonomously.Peer ReviewedPostprint (published version

Chaetoglobosins produced by Chaetomium globosum, endophytic fungus found in association with Viguiera robusta Gardn (Asteraceae)

Endophytes live in association with host plants during all or part of their life cycle without causing any apparent disease. They are considered outstanding and underexploited sources of novel bioactive compounds. Chaetomium globosum was isolated as an endophytic fungus from the healthy leaves of Viguiera robusta. C.globosum is a remarkable producer of chaetoglobosins, which are typically cytotoxic. In this work, chaetoglobosins B (1), D (2) and E (3) have been produced by the endophytic C. globosum strain. Chaetoglobosin B was evaluated against Jurkat (leukemia) and B16F10 (melanoma) tumoral cells and showed 89.55% and 57.10% of inhibition at 0.1 mg mL-1, respectively. Chaetoglobosin B also showed weak antibacterial activity against Staphylococcus aureus (MIC 120 µg/mL) and Escherichia coli (MIC 189 µg/mL).Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Combined method of flow-reduced dump load for frequency control of an autonomous micro-hydropower in AC microgrids

Nowadays, microgrids (MGs) play a crucial role in modern power systems due to possibility of integrating renewable energies into grid-connected or islanded power systems. The Load Frequency Control (LFC) is an issue of paramount importance to ensure MGs reliable and safe operation. Specifically, in AC MGs, primary frequency control of each energy source can be guaranteed in order to integrate other energy sources. This paper proposes a micro-hydro frequency control scheme, combining the control of a reduced dump load and the nozzle flow control of Pelton turbines operating in autonomous regime. Some works have reported the integration of dump load and flow control methods, but they did not reduce the dump load value and adjust the nozzle flow linearly to the power value demanded by users, causing the inefficient use of water. Simulation results were obtained in Matlab®/Simulink® using models obtained from previous research and proven by means of experimental studies. The simulation of the proposed scheme shows that the frequency control in this plant is done in correspondence with the Cuban NC62-04 norm of power energy quality. In addition, it is possible to increase energy efficiency by reducing the value of the resistive dump load by up to 7.5% in a case study. The validation result shows a 60% reduction of overshoot and settling time of frequency temporal behavior of the autonomous micro-hydro.Peer ReviewedPostprint (published version

Extensions to Linguistic Summaries Indicators based on Neutrosophic Theory

The quick development of the markets and companies, especially those that apply information technology, has made it easy to store a large volume of digital information. Nevertheless, the extraction of potentially useful knowledge is difficult; also could not be easily understandable by humans. One of the techniques applied to the solution to this problem is the linguistic data summarizations, whose objective is to discover knowledge to extract patterns from databases, from which are generated explicit and concise summaries. Another important element of the linguistic summaries is the indicators (T) for their evaluation proposed by Zadeh when including linguistic terms evaluation in fuzzy sets. However, these indicators not include the analysis in indeterminate sets. In this paper, it is discussed the use of linguistic data summarization in project management environments and new T indicators are proposed including neutrosophic sets with single value neutrosophic numbers. Authors evaluate T-values proposed by Zadeh and T-values based on neutrosophic theory in the evaluation of linguistic summaries recovered

A New Neutrosophic Cognitive Map with Neutrosophic Sets on Connections

Neutrosophic sets and their application to decision support have become a very important topic. In real situations, there are different sources of indeterminacy. This paper suggests a new decision-making model based on Neutrosophic Cognitive Maps (NCMs) for making comprehensive decisions from a multi-objective approach (diagnosis, decisions, and prediction) during the execution of many projects simultaneously. A Soft Computing technique like Fuzzy Cognitive Maps (FCMs) has been widely used for decision-making process in project management, but this technique has the limitation of not considering the indeterminacy between concepts. This limitation is overcome by the proposed model since NCMs can represent the indeterminacy or neutrality. The new model includes neutrosophic sets in the map’s connections. Finally, the suggested model has been compared with traditional FCM-based model considering efficiency and efficacy