VAr planning using genetic algorithm and linear programming

A combined methodology consisting of successive linear programming (SLP) and a simple genetic algorithm (SGA) solves the reactive planning problem. The problem is divided into operating and planning subproblems; the operating subproblem, which is a nonlinear, ill-conditioned and nonconvex problem, consists of determining the voltage control and the adjustment of reactive sources. The planning subproblem consists of obtaining the optimal reactive source expansion considering operational, economical and physical characteristics of the system. SLP solves the optimal reactive dispatch problem related to real variables, while SGA is used to determine the necessary adjustments of both the binary and discrete variables existing in the modelling problem. Once the set of candidate busbars has been defined, the program implemented gives the location and size of the reactive sources needed, if any, to maintain the operating and security constraints.

Allocation of the cost of transmission losses in a multimarket framework

The paper addresses the issue of apportioning of the cost of transmission losses to generators and demands in a multimarket framework. Line flows are unbundled using equivalent bilateral exchanges on a DC-network model and allocated to generators and demands. Losses are then calculated based on unbundled flows and straightforwardly apportioned to generators and demands. The proposed technique is particularly useful in a multimarket framework, where all markets have a common grid operator with complete knowledge of all network data, as is the case of the Brazilian electric-energy system. The methodology proposed is illustrated using the IEEE Reliability Test System and compared numerically with an alternative technique. Appropriate conclusions are drawn. © The Institution of Engineering and Technology 2006.

Bilevel approach for optimal location and contract pricing of distributed generation in radial distribution systems using mixed-integer linear programming

In this study, a novel approach for the optimal location and contract pricing of distributed generation (DG) is presented. Such an approach is designed for a market environment in which the distribution company (DisCo) can buy energy either from the wholesale energy market or from the DG units within its network. The location and contract pricing of DG is determined by the interaction between the DisCo and the owner of the distributed generators. The DisCo intends to minimise the payments incurred in meeting the expected demand, whereas the owner of the DG intends to maximise the profits obtained from the energy sold to the DisCo. This two-agent relationship is modelled in a bilevel scheme. The upper-level optimisation is for determining the allocation and contract prices of the DG units, whereas the lower-level optimisation is for modelling the reaction of the DisCo. The bilevel programming problem is turned into an equivalent single-level mixed-integer linear optimisation problem using duality properties, which is then solved using commercially available software. Results show the robustness and efficiency of the proposed model compared with other existing models. As regards to contract pricing, the proposed approach allowed to find better solutions than those reported in previous works. © The Institution of Engineering and Technology 2013.

Risk/investment-driven transmission expansion planning with multiple scenarios

This study presents a new methodology based on risk/investment to solve transmission network expansion planning (TNEP) problem with multiple future scenarios. Three mathematical models related to TNEP problems considering multiple future generation and load scenarios are also presented. These models will provide planners with a meaningful risk assessment that enable them to determine the necessary funding for transmission lines at a permissible risk level. The results using test and real systems show that the proposed method presents better solutions compared with scenario analysis method. ©The Institution of Engineering and Technology 2013.

Efeito do cloridrato de dorzolamida a 2%, maleato de timol a 0,5% e associação de ambos na pressão intra-ocular: estudo experimental em cães

Pós-graduação em Medicina Veterinária - FMVZ

Distribuição geográfica e características demográficas da doença trofoblástica gestacional em centro de referência terciária do Estado da Bahia, Brasil

Pós-graduação em Ginecologia, Obstetrícia e Mastologia - FMB

Influência da quimioterapia para neoplasia trofoblástica gestacional sobre a gravidez: resultados maternos e perinatais

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Avaliação da qualidade de vida e aspectos psicológicos em pacientes com doença trofoblástica gestacional

Pós-graduação em Ginecologia, Obstetrícia e Mastologia - FMB

Investigação em 20 anos (1990-2009) da doença trofoblástica gestacional em um Centro de Referência da Região Sudeste do Brasil

Pós-graduação em Ginecologia, Obstetrícia e Mastologia - FMB

Epidemiological Report on the Treatment of Patients with Gestational Trophoblastic Disease in 10 Brazilian Referral Centers Results After 12 Years Since International FIGO 2000 Consensus

OBJECTIVE: To evaluate treatment of Brazilian patients with gestational trophoblastic disease (GTD).STUDY DESIGN: A retrospective cohort study with analysis of medical reports performed in 10 Brazilian referral centers from January 2000 to December 2011.RESULTS: Of 5,250 patients 3 died (0.06%) at the time of uterine evacuation. Spontaneous remission of GTD (group G1) was observed in 4,103 cases, and 1,144 (21.8%) progressed to gestational trophoblastic neoplasia (GTN) (G2). In G1 2,716 (66.2%) had complete hydatidiform mole (HM) and 1,210, partial HM (29.5%); 3,772 patients (92.7%) recovered as noted in December 2012. In G2, of 1,118 patients treated, initial histopathological results of previous gestation were complete HM (77.5% [n = 886]), partial HM (8.8% [n = 100]), and choriocarcinoma (8.0% [n = 92]); 930 (81.3%) were low-risk, 200 (17.5%) were high-risk GTN, and 14 had placental site trophoblastic tumor (PSTT) (1.2%); cure was achieved in 1,078 cases (96.4%), but 26 patients (2.3%) died (4 low-risk [0.4%], 19 high-risk [9.5%], and 3 PSTT [21.4%]).CONCLUSION: The highest death rates were due to high-risk GTN and PSTT. Patients with molar pregnancy should be referred to a referral center for an early diagnosis and prompt treatment of GTN in order to reduce the morbidity and mortality found in advanced stages.

Multiobjective multistage distribution system planning using tabu search

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Short-term expansion planning of radial electrical distribution systems using mixed-integer linear programming

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Reactive power planning under conditional-value-at-risk assessment using chance-constrained optimisation

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Efeitos de uma tarefa dupla e demandas da tarefa no controle postural de adultos jovens

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

New approach for power transformer protection based on intelligent hybrid systems

A power transformer needs continuous monitoring and fast protection as it is a very expensive piece of equipment and an essential element in an electrical power system. The most common protection technique used is the percentage differential logic, which provides discrimination between an internal fault and different operating conditions. Unfortunately, there are some operating conditions of power transformers that can mislead the conventional protection affecting the power system stability negatively. This study proposes the development of a new algorithm to improve the protection performance by using fuzzy logic, artificial neural networks and genetic algorithms. An electrical power system was modelled using Alternative Transients Program software to obtain the operational conditions and fault situations needed to test the algorithm developed, as well as a commercial differential relay. Results show improved reliability, as well as a fast response of the proposed technique when compared with conventional ones.