O transformador de potência é o ativo mais valioso e importante de uma subestação, razão pela qual se faz necessário um acompanhamento especial para estes equipamentos. A operação de qualquer equipamento fora de suas condições nominais é sempre uma situação de risco, porém, tal risco pode ser minimizado através de estudos e análises particulares para cada equipamento.Com os transformadores de potência isso não é diferente, as normas e guias de aplicação de cargas em transformadores prevêem períodos de sobrecarga dentro de algumas condições, porém, há uma grande incerteza nesses dados já que cada transformador envelhece de forma diferente ainda que sejam idênticos de projeto e fabricação. Por essa razão se faz necessária uma análise particular de cada equipamento onde serão identificados os riscos em potencial e a partir daí determinado o grau de confiabilidade do equipamento. Com base em informações históricas dos equipamentos e algoritmos desenvolvidos com base nas normas vigentes, foi desenvolvido o Sistema Integrado de Gestão denominado SGT. Através deste sistema será possível armazenar de forma organizada as informações de todas as unidades fornecendo subsídios para uma tomada de decisão minimizando os riscos. Através do Sistema Integrado será possível estabelecer uma base única de consultas, promovendo assim a otimização destes equipamentos face a regulação do setor elétrico. / The power transformer is the most valuable and important assets of a substation, for that reason is necessary a special attendance for these equipments. The operation of any equipment out of their nominal conditions it is always a risk situation, however, such a risk can be minimized through studies and private analyses for each equipment. Power transformers are not different, the norms and guides of load application foresee overload periods under some conditions, however, and there is a great uncertainty in those data since each transformer ages in a different way although they are identical of project and production. For that reason are necessary peculiar analysis of each equipment where you/they will be identified the potential risks and since then certain the degree of reliability of the equipment. Based in historical informations of the equipments and algorithms developed in agreement with the effective norms, the Integrated System of Management was developed and denominated SGT. Through this system it will be possible to store in an organized way the information of all of the units, supplying subsidies to have a safe decision minimizing the risks. Through the Integrated System it will be possible to establish an only base of consultations, promoting the assets optimization based in the new regulation of the electric section.

O transformador de potência é o ativo mais valioso e importante de uma subestação, razão pela qual se faz necessário um acompanhamento especial para estes equipamentos. A operação de qualquer equipamento fora de suas condições nominais é sempre uma situação de risco, porém, tal risco pode ser minimizado através de estudos e análises particulares para cada equipamento.Com os transformadores de potência isso não é diferente, as normas e guias de aplicação de cargas em transformadores prevêem períodos de sobrecarga dentro de algumas condições, porém, há uma grande incerteza nesses dados já que cada transformador envelhece de forma diferente ainda que sejam idênticos de projeto e fabricação. Por essa razão se faz necessária uma análise particular de cada equipamento onde serão identificados os riscos em potencial e a partir daí determinado o grau de confiabilidade do equipamento. Com base em informações históricas dos equipamentos e algoritmos desenvolvidos com base nas normas vigentes, foi desenvolvido o Sistema Integrado de Gestão denominado SGT. Através deste sistema será possível armazenar de forma organizada as informações de todas as unidades fornecendo subsídios para uma tomada de decisão minimizando os riscos. Através do Sistema Integrado será possível estabelecer uma base única de consultas, promovendo assim a otimização destes equipamentos face a regulação do setor elétrico. / The power transformer is the most valuable and important assets of a substation, for that reason is necessary a special attendance for these equipments. The operation of any equipment out of their nominal conditions it is always a risk situation, however, such a risk can be minimized through studies and private analyses for each equipment. Power transformers are not different, the norms and guides of load application foresee overload periods under some conditions, however, and there is a great uncertainty in those data since each transformer ages in a different way although they are identical of project and production. For that reason are necessary peculiar analysis of each equipment where you/they will be identified the potential risks and since then certain the degree of reliability of the equipment. Based in historical informations of the equipments and algorithms developed in agreement with the effective norms, the Integrated System of Management was developed and denominated SGT. Through this system it will be possible to store in an organized way the information of all of the units, supplying subsidies to have a safe decision minimizing the risks. Through the Integrated System it will be possible to establish an only base of consultations, promoting the assets optimization based in the new regulation of the electric section.

" Estimating Life Loss for Dam Safety Risk Assessment" explores the need for a new life-loss model in dam safety risk assessment, historical foundations on which that model can be built, and issues that are critical for a successful life-loss model to address. After critiquing existing life-loss models, the work presents a summary of historical insights that were derived by characterizing flood events on the level of subpopulations at risk, using nearly l 00 carefully defined variables. Building upon both conceptual and historical insights, the work culminates by presenting the conceptual basis for a new life-loss model that remains under development. Chapter I introduces the topic of dam safety risk assessment and the central role that life-loss estimation plays in that field. Chapter II discusses important preliminary considerations in model development. Chapter Ill provides a detailed review of previous life-loss models that pertained to floods, including a critique of each. Chapter IV explores the DeKay-McClelland model in detail and raises serious concerns regarding its future use. Chapter V defines nearly l 00 variables and their respective categories for use in characterizing flood events. Chapter VI provides a detailed outline of historical insights that relate to flood events in one of 18 logical categories. Chapter VII proposes the framework for a new conceptual life-loss model-a model that is still under development and has yet to be refined or offered for testing-with sufficient details to indicate how it was developed and how it might be used. Chapter VIII provides a summary, conclusions, and recommendations for future research. Appendices A through D provide material related to over 900 pages of unpublished working documents developed while characterizing 38 flood events and nearly 200 subpopulations at risk. Appendix E offers a summary of existing software that, given additional development, might prove useful to life-loss estimation in dam safety risk assessment.

Catastrophic events such as dam failures or severe floods are considered to be of low probability, although their consequences can be extremely high and might include loss of life. Earlier studies have linked circumstances surrounding historical darn failure events to actual loss of life and produced formulations using statistical analysis of these events. Shortcomings of these methods include the inability to adjust life-loss estimates based on the type of darn failure, global averaging of population at risk, and ignoring the dynamics of the evacuation process. The main objective of this research is to develop a practical and improved life-loss estimation approach for use in dam safety risk assessment and emergency planning. The methodology is specifically formulated to overcome the limitations of previous. purely empirical, approaches. The approach takes into account the spatial and temporal distribution of flood water depth and velocity, fate of buildings, simulation of warning diffusion, and tracking the movement of people from their original location towards safe shelters. The model created, called LlFESim, is designed to serve multiple function s. First, it can be used in a Deterministic Mode using best estimate inputs to obtain point estimates, or to test different policies for evacuation as well as different times of the day and for different dam breach flooding scenarios. Second, the Uncertainty Mode represents input and parameter uncertainties to provide estimates of life loss, and other variables relating to warning and evacuation effectiveness, as probability distributions. These distributions of life loss can be combined with estimates of the uncertainties in other risk assessment inputs, to obtain estimates of uncertainties in risk assessment results, including evaluations against tolerable risk guidelines. Two communities were used to demonstrate the model performance. Deterministic Mode results display the various possible model outputs. Sensitivity analysis for the Deterministic Mode shows that the effect of warning issuance time is the dominant factor in the estimated life loss. However, other factors play an important role such as the time of day, effectiveness of the warning system, and shelter location. Uncertainty Mode results demonstrate the effect of uncertainties in model parameters and inputs on the model results.

Abstract in English, Tsonga and Zulu / Mitlumbo ya mifambafambo ya le magondzweni i xin’wana xa miringeto (risks) yo biha ku tlula hinkwayo ya swifambo swa le gondzweni emisaveni hinkwayo, leswi yimelaka xiphiqo lexikulu xa swohanyaswin’we-ikhonomi ngopfu-ngopfu eka matiko lama ya ha hluvukaka tanihi Afrika-Dzonga. Ku va ku nyikiwa masungulo yo tiya ya xiikhonomi eka swiboho swa mbekiso ku tirhana na ntlhontlho lowu, i swa nkoka swinene ku hlela ndhurho wa mitlumbo leyi. Mipimanyeto leyi yi tirha tanihi nxopaxopo wa swinghenisiwa swa mbuyelo wa ndhurheriwo ku endlela ku kuma mphakelo wa switirhisiwa wo tirha kahle eka ku nghenelela eka ku tirhana na mitlhontlho leyi vangiwaka hi mitlumbano ya le magondzweni. Tiko ra Afrika-Dzonga a ri nga ri ku pfuxeteni ka mahungu ya mipimanyeto ya midurho ya mitlumbano ya le magondzweni nkarhi na nkarhi, naswona leyi a yi endliwa a yi tirhisa maendlelo lamo soriwa ngopfu yo languta nkoka wa vanhu (human capital). Hikwalaho, mipimanyeto leyi nga kona a yi nga ta va leyi tshembekaka eka ku kunguhata na ku pimaniseka na mipimanyeto ya matiko man’wana. Hi le ka ku landzelela vundzhaku lebyi laha dyondzo leyi yi nga tumbuluka na ku kombisa matirhiselo ya rimba ra ntirho wo katsa (hybrid) ku kambela ndhurho wa mitlumbo ya swifambo swa le magondzweni eAfrika-Dzonga. Rimba leri ri tirhisa endlelo ro kongomisa eka nkoka wa vanhu na ku pfumela ku hakela (willingness-to-pay), eka dyondzo yi ri yin’we. Mipimanyeto ya midurho ya nkoka wa vanhu ya laveka ku va yi pfuna eka ku kunguhata leswaku yi tlakusa swinenenene swihumesiwa swa rixaka, loko hala tlhelo mipimanyeto yo pfumela ku hakela yona yi ri yona yi fanelaka swinene eka ku pfuneta minghenelelo yo tlakusa nhlayiseko wa vanhu hi ku hunguta ku vaviseka na ku fa. Endlelo ro pfumela ku hakela ri tirhisa maendlelo ya swo ka swi nga ri swa makete (contingent valuation) na ya maendlelo yo langa (preference). Khwexinere yo valanga leyi a yi ri na maendlelo yo ka ya nga ri ya swa makete na swilangiwa leswi a swi boxiwile, yi tirhisiwile hi magoza mambirhi ku sampula vaanguri va 273 eka ntirho wa swo tleketla. Eka mhaka ya endlelo ro kongomisa eka nkoka wa vanhu, mipimanyeto ya ndhurho eka xiviko xa 2016 xa Cost of Crashes in South Africa yi hundzuluxiwile hi ku katsa inifulexini, ku tirhisiwa mpimo wa 2017 wa 5.3% ku kuma mipimanyeto ya ndhurho ya 2017. Dyondzo leyi yi paluxile leswaku endlelo ro kongomisa eka nkoka wa vanhu ri kayiveta ku vona ndhurho wa mitlumbo ya le magondzweni. Dyondzo leyi yi hoxa xandla eka ntsengo wa vutivi hi ku tirhisa endlelo ro languta nkoka wa vanhu na endlelo ro pfumela ku hakela eka dyondzo yi ri yin’we ku kombisa ntirhiseko wa endlelo leri ra nkatso (hybrid)/nhlanganiso eka xiyimo xa Afrika-Dzonga. Ndzavisiso wa nkarhi lowu taka wu fanele ku engeta dyondzo leyi hi sampulu leyi humaka eka swifundzakulu hinkwaswo swa nkaye swa Afrika-Dzonga, leswaku mipimanyeto ya ndhurho yi yimela vanhu va tiko hinkwaro. / Road traffic crashes are one of the worst risks of road mobility worldwide, representing a huge socio-economic problem particularly in developing countries such as South Africa. In order to provide a sound economic basis for investment decisions to address this challenge, it is critical to assess the cost of these crashes. These estimates serve cost-benefit analysis inputs to facilitate a more efficient resources allocation for interventions to address the challenge posed by road crashes. South Africa has not been updating crash cost estimates on a regular basis, and those that were conducted used the much criticised human capital approach. Therefore, the available estimates could not be relied upon for planning purposes and comparison with the estimates of other countries. It is against this background that this study developed and illustrated the application of a hybrid framework for assessing the cost of road traffic crashes in South Africa. The framework uses the human capital approach and the willingness-to-pay approach in one study. Human capital approach cost estimates are needed to inform planning to maximize the national output, while the willingness-to-pay estimates are more suitable when the main concern is to inform interventions to increase social welfare by reducing injuries and fatalities. The willingness-to-pay approach uses the contingent valuation and the stated preference methods. A survey questionnaire with contingent valuation and stated preference questions was administered in two phases to a sample of 273 respondents within the transport industry. For the human capital approach, the cost estimates in the 2016 Cost of Crashes in South Africa report were adjusted for inflation using the 2017 rate of 5.3% to obtain 2017 cost estimates. This study revealed that the human capital approach underestimates the cost of road crashes. The study contributes to the body of knowledge by using the human capital approach and the willingness-to-pay approach in one study to illustrate the applicability of this hybrid/ combination within the South African context. Future research needs to replicate this study on a sample drawn from all nine provinces of South Africa, so that the cost estimates are representative of the country’s population. / Ukuphazamiseka komgwaqo kungenye yezingozi ezimbi kakhulu zokuhamba komgwaqo emhlabeni jikelele, ezimele inkinga enkulu yenhlalo nezomnotho ikakhulukazi emazweni asathuthuka njengeNingizimu Afrika. Ukuze unikeze isisekelo sezomnotho esizwakalayo ezinqumeni zokutshala izimali ukubhekana nale nselele, kubalulekile ukuhlola izindleko zalezi zingozi. Lezi zilinganiso zisebenza njengeziphakamiso zokuhlaziywa kwezindleko zokuhlomula ukuze kube lula ukunikezwa kwezinsiza ezenzelwe ukuxazulula inselele ebangelwa ukuphazamiseka komgwaqo. INingizimu Afrika ayizange ibuyekeze ukulinganisa izindleko zezingozi njalo, futhi lezo ezenziwa zisebenzise indlela enkulu yokugxeka ukusebenzisa abantu. Ngakho-ke, izilinganiso ezitholakalayo azikwazanga ukuthenjelwa kuzona ngezinjongo zokuhlela nokuqhathaniswa nezilinganiso zamanye amazwe. Lokhu kuphikisana nalesi sigaba ukuthi lolu cwaningo lusungulwe futhi luboniswe ukusetshenziswa kohlaka oluxubile lokuhlola izindleko zokuphazamiseka komgwaqo eNingizimu Afrika. Uhlaka lusebenzisa indlela yokusebenzisa abantu kanye nendlela yokuzimisela-ukukhokha ocwaningweni olulodwa. Ukulinganiselwa kwezindleko zokusebenzisa abantu kuyadingeka ukuze kwaziswe ukuhlela ukwandisa umkhiqizo kazwelonke, kanti ukulinganiselwa kokuzimisela-ukukhokhela kukulungele kakhulu ukwazisa ukungenelela ukwandisa inhlalakahle yomphakathi ngokunciphisa ukulimala nokubulawa kwabantu. Indlela yokuzimisela-ukukhokha isebenzisa ukuhlaziywa kwesilinganiso kanye nezindlela okukhethwa ngazo. Imibuzo yokuhlola ngokuhlaziywa kwesilinganiso kanye nemibuzo ekhethwe ngayo yenziwa ngezigaba ezimbili embonakalisweni yabaphendulile abangama-273 embonini yezokuthutha. Ngokwendlela yokusebenzisa abantu, izindleko ezilinganiselwa ku-2016 Izindleko Zokushayisana eNingizimu Afrika kubikwa ukuthi zalungiselwa ukwenyuka kwamandla emali, kusetshenziswa isilinganiso sango-2017 esingu-5.3% ukuthola izindleko zango-2017. Lolu cwaningo luveze ukuthi indlela yokusebenzisa abantu ithatha kancane izindleko zokuphazamiseka komgwaqo. Ucwaningo lunomthelela emzimbeni wolwazi ngokusebenzisa indlela yokusebenzisa abantu kanye nendlela yokuzimisela-ukukhokha ocwaningweni olulodwa ukukhombisa ukufaneleka kwalesi sivumelwano / inhlanganisela ngaphakathi komongo waseNingizimu Afrika. Ucwaningo lwesikhathi esizayo ludinga ukuphindaphinda lolu cwaningo embonakalisweni othathwe kuzo zonke izifundazwe eziyisishiyagalolunye zaseNingizimu Afrika, ukuze ukulinganiswa kwezindleko kummele abantu bezwe / Business Management / D. Phil. (Management Studies)