Showing papers by "CHESF published in 2016"
TL;DR: Limnoperna fortunei (Dunker, 1857) is a small mytilid native to Southeast Asia and it was introduced in South America in early 1990 and has dispersed from Argentina to central Brazil, and until 2014 has been restricted mainly to the Parana and Uruguay river basins as mentioned in this paper.
Abstract: Limnoperna fortunei (Dunker, 1857) is a small mytilid native to Southeast Asia. It was introduced in South America in early 1990 and has dispersed from Argentina to central Brazil, and until 2014 has been restricted mainly to the Parana and Uruguay river basins. The present note reports the occurrence of Limnoperna fortunei for the first time in the Sao Francisco River basin in northeastern Brazil. The establishment of L. fortunei in these regions will require close attention from the government and also by society.
49 citations
TL;DR: A Bayesian population variability method is proposed for the estimation of the distributions of the rates of accident and recovery and a Markov-based model will be used to estimate the uncertainty over the expected number of accidents and the work time loss.
19 citations
24 Jul 2016
TL;DR: This paper explores the advantages offered by the nonparametric methods for modeling of wind turbine power curve, because the application of nontraditional techniques enhances the accuracy and is easy to implement.
Abstract: The modeling of wind power curve is important in turbine performance monitoring and in wind power forecasting. There are several techniques to fit the power curve of a wind turbine, which can be classified into parametric and nonparametric methods. This paper explores the advantages offered by the nonparametric methods for modeling of wind turbine power curve, because the application of nontraditional techniques enhances the accuracy and is easy to implement. We study two nonparametric methods to estimate the wind turbine power curve: Artificial Neural Networks (ANN) and Fuzzy Inference System (SIFs). Actual case studies were carried out from two wind farms in northeastern Brazil. The models were adjusted to forecast the wind power with steps from 1 to 24 hours ahead. When compared to the reference models, the developed models' gains lay in the range of 29 to 60%, for forecasts in a period of twenty-four hours ahead. The results were compared and have shown that the models created have a very promising performance.
8 citations
1 Oct 2016
TL;DR: In this article, real-time digital simulator studies for performance evaluation of the Taua II SVC (−45 to 90Mvar / 230kV) are presented in order to verify the feasibility of using conventional FACTS devices to voltage control in electric power systems.
Abstract: Real time digital simulator studies for performance evaluation of the Taua II SVC (−45 to 90Mvar / 230kV) are presented in this paper. Due to the low short-circuit levels at the SVC point of common coupling and to the presence of resonances associated to harmonics higher than the eleventh, it was adopted a configuration considering a series blocking reactor at SVC medium voltage busbar. It is demonstrated the fulfillment of the Specification requirements and despite of the technological progression of voltage source converter SVCs, the viability of using conventional FACTS devices to voltage control in electric power systems is demonstrated due to its satisfactory performance and competitive cost.
3 citations
TL;DR: This paper presents a meta-modelling study comparing the models used in the CEERMA Center for Risk Analysis, Reliability and Environmental Modeling and those used in CHESF-SãoFrancisco’s Hydroelectric Company.
1 citations
22 Aug 2016
TL;DR: A strategy for legacy systems based on three disciplines which guide the adoption of secure routines while avoid production drop is presented, including a prototype framework and its success in providing security to the network of a power plant is discussed.
Abstract: Security is a well-known critical issue and exploitation of vulnerabilities is increasing in number, sophistication and damage. Furthermore, legacy systems tend to offer difficulty when upgrades are needed, specially when security recommendations are proposed. This paper presents a strategy for legacy systems based on three disciplines which guide the adoption of secure routines while avoid production drop. We present a prototype framework and discuss its success in providing security to the network of a power plant.