Wind Turbine Generator Reliability: An Exploration of the Root Causes of Generator Bearing Failures

Increasing the availability of multi-megawatt wind turbines (WT) is necessary if the cost of energy generated by wind is to be reduced. Reliability surveys have shown that WT generator bearings have a relatively high failure rate, with failures happening too early to be due to classical rolling contact fatigue. It has been the purpose of the present work to demonstrate the value of models which may help to explain some of the failure modes of wind turbine generators (and their root causes). The work has considered two potential root causes of wind turbine generator failure. Firstly, gearbox-generator misalignment caused by deflection of the compliant drivetrain under loading. Secondly, electrical discharge machining (EDM) of the generator bearings due to the common-mode voltage caused by pulse width modulation (PWM) of the power electronics. Numerical simulations have been used to investigate these potential failure modes and to show how they bring about premature failure. It has been shown that there exists a mechanism by which gearbox-generator misalignment can exacerbate EDM. This demonstrates the importance of holistic analyses of WTs, which are complex electromechanical systems with non-trivial interactions between sub-assemblies. The need for further research has been shown

Doctor of Philosophy

dissertationThis dissertation consists of three papers, each of which addresses what I believe are important gaps in the literature. The first is the impact regional asymmetric costs can have on mitigation and adaptation decisions. Regional cost asymmetries are not unknown in the extant literature, but their implications are generally ignored in much of the modeling that exists. The second gap involves the cursory treatment climate science findings receive in macroeconomic modeling. Development of climate system dynamics from climate science has continued over the last two decades, but little progress has been made on incorporating new developments into post-Keynesian macromodels. Finally, the third gap is the lack of time series methods in the empirical research on the climate-macroeconomic interaction from a global perspective. It is known that GDP (Gross Domestic Product) and CO2 production are highly related, but questions remain as to how this relation works and whether it is changing over time

“These dogs will do as we say”: African nationalism in the era of decolonization in David Caute’s At Fever Pitch and Frantz Fanon’s The Wretched of the Earth

This article examines responses to the impact of colonialism on post-independence national unity in Africa from the perspective of the colonizer and the colonized. Written out of experience of decolonization in Ghana, At Fever Pitch, published in 1959 by the British novelist David Caute, depicts western models of economic development and nationhood as derailing the emancipatory possibilities of colonial self-determination. It is a preoccupation that was also central to anti-colonial political thought during the era of decolonization, most notably in Frantz Fanon’s The Wretched of the Earth (1965), and would become highly contested in the field of postcolonial studies. Rather than viewing the perspectives of the colonizer as fundamentally antithetical to postcolonial politics, this article analyses the way in which Caute and Fanon mount two distinct but not oppositional critical responses to the transfer of power from European imperial elites to a self-interested national middle class. By attending to the form of At Fever Pitch, moreover, this paper will register the extent to which Caute’s intervention into debates about the rise of nationalism in the colonies disrupts prevailing interpretations of British “end of Empire” fiction as mourning the end to British colonial dominance

Hostile environments, climate justice, and the politics of the lifeboat

This article explores how migration and ecological crises need to be addressed together by examining the most common analogy to emerge in critical and creative responses to the relationship between climate breakdown and global mobility - that of individual nation-states as lifeboats. To demonstrate this, I analyse the ways in which John Lanchester’s The Wall (2019) and Alexis Wright’s The Swan Book (2013) reveal how dystopian fiction is able to stage, satirize, and confront the stark premises of the nation-as-lifeboat analogy. Lastly, by placing Wright’s depiction of the confluent experiences of environmental refugees and Aboriginal Australians in dialogue with the perspectives of Native American (specifically Potawatomi) scholars, Kyle Whyte and Robin Wall Kimmerer, I demonstrate how debates about mobility, climate catastrophe, and interspecies relations need to be informed by Indigenous science and storytelling

‘The hollow shell of nationality’: Competing nationalisms and the emergence of dictatorship in David Caute’s At Fever Pitch

In its depiction of the hijacking of the African nationalist movement by a self-serving African middle-class, David Caute’s At Fever Pitch (1959) disrupts unilinear conceptions of British literature of decolonisation and complicates contemporary postcolonial debates around nationalist ideology and practice. Synchronic and diachronic accounts of British literature and the end of Empire have tended to focus on a shared preoccupation with imperial retrenchment (Taylor 1993, Sinfield 1997: 2004, Esty 2004), while the re-emergence of regionalism and state control in developing countries since decolonisation has led many postcolonial critics to view nationalism, as Laura Chrisman holds, as ‘inherently dominatory, absolutist, essentialist and destructive’ (2004: 183). In At Fever Pitch, however, Caute foregrounds the complex transition to independence in Africa and depicts the emergence of a totalitarian form of nationalism as a legacy of British colonial rule

The narrative practices of hostile environments: the story of the nation-as-family and the story of security

This article contributes to research into the importance of storytelling in asylum practice by examining the narratives used to promote and justify Hostile Environment policies. The two narrative practices identified are the “story of the nation-as-family”, which defines national belonging predominantly by markers of race and ethnicity, and the “story of security”, whereby racialized refugees are framed as potential threats to the nation's socio-economic stability. The former propagates a notion of consanguinity that works to exclude and silence people seeking asylum from non-European nations. The latter sees the rhetoric of a “clash of civilisations” so central to the “War on Terror” taken up in policy debates about climate-induced migration. An analysis of the way in which these stories are staged and critiqued in the writing of Abdulrazak Gurnah and Stephen Collis reveals how they elide the relationship between forced migration and the history of European colonialism. In exploring this elision, this article insists on the significance of literary texts as spaces where monocultural conceptions of belonging can be confronted, and where understanding Europe's colonial past is established as an integral part of hearing the stories of refugees in the present