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Article
Publication date: 8 May 2018

Phamella Reinert Tamanini Piccoli, Sérgio Henrique Lopes Cabral, Luiz Fernando de Oliveira, Odirlan Iaronka, Diogo Fernando Harmel, João Paulo Vieira and João Egídio Sapeli

This paper aims to present the proposition of a new experimental method for obtaining very crucial data of the structural steel that is used in the tank of oil filled power…

Abstract

Purpose

This paper aims to present the proposition of a new experimental method for obtaining very crucial data of the structural steel that is used in the tank of oil filled power transformers, namely, the volumetric losses and the magnetic permeability, both in function of the density of magnetic flux. Although these data are not usually available, they are fundamental for helping the transformer designer in avoiding the occurrence of hot spots in the transformer tank. The adoption of a conventional Epstein frame has restrictions because of the incompatibility between it and the samples of the steel.

Design/methodology/approach

The basis of the proposition is the same as that of the Epstein frame, with significant attention paid to the additional losses in the winding that creates the magnetic flux to the samples in the core. These losses can be significant and are created by the harmonics of current along the windings and are summed to the ohmic losses. For separating these winding losses from the magnetic losses, each sample is made as being the core of a toroidal 1:1 transformer. Thus, two tests with two identic of these toroidal transformers are necessary.

Findings

The proposed methodology is simple, because it is very similar to the classical tests of transformers (no-load and short-circuit tests). The process of separation of losses requires only a numerical fitting of curves for adjusting the winding losses as a function of the current amplitude, and the obtained results are coherent with the expected behavior of the magnetic losses and the magnetic permeability of a structural steel.

Research limitations/implications

The method gives very approximate results in comparison to those obtained using the Epstein frame. The influences of the temperature and/or of the skin effect have not been evaluated.

Practical implications

Practical, real and thus confident data of structural steel, such as the magnetic permeability and the volumetric losses (hysteresis and Foucault), become available for the transformer designer to take actions for not only reducing the tank losses but also for avoiding the occurrence of hot spots through computer simulation.

Originality/value

The proposition is very new, as it allows to test steel samples with a size that does not fit to a usual Epstein frame. It takes into account the real influence of harmonic of currents in the losses along the winding of a classical Epstein frame, which has not been so far mentioned. It allows obtaining data of structural steel that had not been considered important until now.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 37 no. 3
Type: Research Article
ISSN: 0332-1649

Keywords

Book part
Publication date: 23 March 2017

Barbara de Lima Voss, David Bernard Carter and Bruno Meirelles Salotti

We present a critical literature review debating Brazilian research on social and environmental accounting (SEA). The aim of this study is to understand the role of politics in…

Abstract

We present a critical literature review debating Brazilian research on social and environmental accounting (SEA). The aim of this study is to understand the role of politics in the construction of hegemonies in SEA research in Brazil. In particular, we examine the role of hegemony in relation to the co-option of SEA literature and sustainability in the Brazilian context by the logic of development for economic growth in emerging economies. The methodological approach adopts a post-structural perspective that reflects Laclau and Mouffe’s discourse theory. The study employs a hermeneutical, rhetorical approach to understand and classify 352 Brazilian research articles on SEA. We employ Brown and Fraser’s (2006) categorizations of SEA literature to help in our analysis: the business case, the stakeholder–accountability approach, and the critical case. We argue that the business case is prominent in Brazilian studies. Second-stage analysis suggests that the major themes under discussion include measurement, consulting, and descriptive approach. We argue that these themes illustrate the degree of influence of the hegemonic politics relevant to emerging economics, as these themes predominantly concern economic growth and a capitalist context. This paper discusses trends and practices in the Brazilian literature on SEA and argues that the focus means that SEA avoids critical debates of the role of capitalist logics in an emerging economy concerning sustainability. We urge the Brazilian academy to understand the implications of its reifying agenda and engage, counter-hegemonically, in a social and political agenda beyond the hegemonic support of a particular set of capitalist interests.

Details

Advances in Environmental Accounting & Management: Social and Environmental Accounting in Brazil
Type: Book
ISBN: 978-1-78635-376-4

Keywords

Book part
Publication date: 24 June 2017

Maria Alice Nunes Costa, Lucia Bravo, Elaine Borin and José Eduardo Pereira Filho

This chapter discusses the Operation Lava Jato (or Operation Car Wash) which is an ongoing investigation in Brazil, since 2014, by the Federal Police and the Federal Public…

Abstract

This chapter discusses the Operation Lava Jato (or Operation Car Wash) which is an ongoing investigation in Brazil, since 2014, by the Federal Police and the Federal Public Ministry. This Operation triggered systemic and endemic corruption among companies, self-described as socially responsible, the State, and Brazilian Government. The analysis is based on empirical data available on the internet and in the Brazilian press about “Operation Car Wash” (Operation Lava Jato) and its socio-legal implications. We conclude that when a society has a historical and cultural tradition permeated by close private and patrimonial relations between government and companies, this fact negatively impacts the economic performance and the adoption of ethical behavior and social responsibility. This case study examines the recent police investigation into corruption involving companies and governments in a Latin American country. It provides empirical and historical data on the nature of the capitalism of ties model developed in Brazil that impacts on economic performance and the strategic proposal of corporate social responsibility.

Details

Corporate Social Responsibility and Corporate Governance
Type: Book
ISBN: 978-1-78714-411-8

Keywords

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