MSc (Mathematics) / Department of Mathematcs and Applied Mathematics / Magnetohydrodynamics ows have gained signi cant attention due to their importance in engineering applications. In this study, we numerically analysed the Dufour and Soret e ects on an unsteady MHD mixed convection ow past an in nite vertical plate with viscous dissipation. The governing non-linear partial di erential equations (PDEs) are transformed into a system of ordinary di erential equations (ODEs) by the suitable similarity transformations. The resulting equations consist of the momentum, energy and mass di usion equations. These resulting equations are solved using the Spectral Local Linearization Method (SLLM). Results obtained by the SLLM are in good agreement with the bvp4c technique. The e ects of di erent physical parameters entering into the problem are displayed graphically. The values of the Skin-friction (f0(0)), Nusselt number (􀀀 0(0)) and Sherwood number (􀀀 0(0)) are shown in tabular form for di erent values of the parameters. From the results, it is noted that the Soret number (Sr) and the Dufour number (Du) have negligible e ects on temperature pro le, whereas the decrease in the Soret number (Sr) leads to a decrease in both velocity and concentration of the uid, and the increase in Dufour number (Du) reduces the velocity and also has negligilbe e ect on the concentration pro le. / NRF

Globally, a significant portion of energy comes from hydropower. However, harnessing hydro energy interrupts the natural state of river flows, thus affecting the ecological processes of the surrounding communities. In this thesis, a water level control model is described to sustain a desired head for a hydropower plant despite the nature of the stream flows. A scientific analysis is carried out on the physical set up of a hydropower reservoir via mathematical modelling. The study depicts that the amount of electric power, Pe(t) generated from a specific hydro reservoir is mainly controlled by the current water level, h(t) and its corresponding outflow volumes, fout(t). However, these two variables are largely constrained by the behaviour of the inflow volumes, fin(t). So, by relating the torque-force balance equations of all the dynamic elements involved we develop a mathematical model that maintains a steady water level at sustainable inflow rates. The Routh-Hurwitz stability criterion and the Final Value theorem are applied to decide the PD-control actions that stabilize the system. The penstock cross-sectional area, Ap is varied to attain the correct fout(t) for the desired h(t). The model behaviour is verified using Simulink simulation software. Eventually, the model accounts for hydroelectric power production patterns that depends on the nature of the stream flow rates.

Environmental impact assessment follow-up has been widely addressed by various researchers. However, there is still a gap in the actual implementation of this process. This study addresses this gap by evaluating the effectiveness of implementing the environmental authorizations of Eskom’s Kusile and Medupi Power Stations during the construction phase. The main aim of the study is to determine whether the environmental authorization conditions were effectively implemented by project developers and whether full compliance which could lead towards sustainable development was at the forefront of Kusile and Medupi developments. The survey method was used whereby questionnaires were formulated and completed by fifty (50) participants involved in the implementation of both power stations’ environmental authorizations. The results showed that the importance of protecting the environment and overall compliance with the projects’ environmental authorization conditions are well understood and implemented. However, some of the responses indicated the difficulty in implementing certain environmental authorization conditions such as retaining existing vegetation cover. About Nineteen (19) external audit reports (of which nine were for Kusile and ten for Medupi) between the periods of 2008 to 2014 were reviewed and the audit results shown good percentage of over 90% compliance with the environmental authorization at both power stations. In conclusion, the environmental authorizations were well implemented by both Kusile and Medupi Power Stations. The environmental management through compliance with the environmental authorization is at the forefront of the Eskom’s developments and thus promotes sustainable development. The outcome of this study has a wide application that includes application to any new project that involves building infrastructure. / Environmental Sciences / M. Sc. (Environmental Management)

Thesis (MDF)--Stellenbosch University, 2009. / ENGLISH ABSTRACT: The electricity crisis presently affecting Africa is forcing govenments in the region to increasingly consider independent power developers as a means to help mitigate the imbalance between the demand and the supply of electricity. However, the success of this initiative will depend entirely upon governments' ability to create an environment that is conducive to developing private electricity generation plants. This paper focuses on Africa's independent power producer (IPP) market, evaluating the context in which it would develop. It also assesses how issues such as the complexity and uncertainty surrounding power purchase agreements, the current level of electricity tariffs, the incompleteness of power sector refonn as well as risk-sharing agreements between IPPs and the utilities are affecting the electricity market in the region. The analysis has broader implications for potential independent power projects as it not only questions the longterm sustainability of these but also provides strategic recommendations as to how to best maneuver in an environment fraught with major challenges. / AFRIKAANSE OPSOMMING: Die huidige elektrisiteitskrisis wat Suidelike-Afrika affekteer veroorsaak dat owerhede in die streek al hoe meer die moontlikheid van onafhanklike elektrisiteit produsente ondersoek om die wanbalans tussen elektrisiteit aanvraag en lewering te beperk. Die sukses van die initiatief is egter totaal afhanklik van die owerhede se vermoe om 'n omgewing te skep wat aantreklik is vir die ontwikkeling van privaat sektor kragsentrales. Hierdie verslag fokus op die Suidelike-Afrika onafhanklike elektrisiteit produsente mark, met 'n fokus op die konteks waarbinne dit moet ontwikkel. Dit ontleed verder die kompleksiteit en onsekerheid van krag aankoop kontrakte, die huidige vlakke van elektrisiteitstariewe, die tekort aan elektrisiteits sektor hervorming asook risiko-delende kontrakte tussen onafhanklike elektrisiteit produsente en nasionale elektrisiteitsverskaffers in Suidelike-Afrika. Die analise het breer implikasies vir potensiele onafhanklike elektrisiteit projekte aangesien die lang-termyn volhoubaarheid van sulke projekte bevraagteken word, maar gee ook strategiese aanbevelings oor hoe om die mark te betree met vele uitdagings.

Nas últimas décadas, a fonte eolielétrica é a que sinaliza maior crescimento mundial dentre as demais. A curva de aprendizagem tecnológica do setor mostra queda do custo entre 15% a 20% a cada 3 anos. Países ativos no setor eólico se esforçam pela meta de 12% de participação na produção elétrica mundial em 2020. A contribuição da geração eolielétrica offshore é fundamental para essa meta, pela proximidade aos centros de carga, com ganhos de eficiência, de escala e reduzido impacto ambiental e visual. Apesar do crescimento do parque gerador nacional em 2006, há carência na produção no curto prazo. Contraditoriamente, há ventos abundantes para geração eolielétrica e o prévio arcabouço industrial que seria necessário para desenvolver o setor. Apesar do incentivo governamental (PROINFA), o setor eólico brasileiro ainda não decolou como esperado. O objetivo deste trabalho é reforçar o debate sobre a importância da diversificação da matriz, em prol da estratégia de segurança do suprimento energético nacional e da redução da emissão de gases de efeito estufa. Em rumo a esse objetivo, são colocados argumentos com abordagem ampla e com abordagem específica. Na abordagem ampla, esta pesquisa propõe uma maior inserção da fonte eólica na matriz elétrica nacional como uma das opções a serem consideradas de maneira mais relevante nas táticas de diversificação da matriz, a exemplo do que já fazem países com maior abundância de gás natural que o Brasil, como o Reino Unido. Sob um ponto de vista específico, a investigação exemplifica possibilidades de contribuição da fonte eolielétrica, na sua versão offshore, para as táticas de diversificação da matriz nacional que se entendem importantes, a exemplo do já fazem países com maior predominância da fonte hidráulica que o Brasil, como a Noruega. O método utilizado para se alcançar o objetivo desta dissertação envolve os seguintes passos: (1) esclarecer quanto aos principais aspectos do setor energético a nível mundial e o problema ambiental que está vinculado à produção de energia por fontes fósseis; (2) esclarecer quanto aos aspectos do desenvolvimento de sistemas eolielétricos onshore no Brasil e no mundo e também do desenvolvimento de sistemas offshore em países de interesse; (3) explorar exemplos de articulação dos sistemas eólicos offshore com projetos de produção de energia fóssil em ambiente marítimo, como forma de produzir sinergia útil a ambos os setores; (4) analisar e debater sobre as propostas do governo brasileiro para o futuro da matriz elétrica do país; (5) propor algumas possibilidades de desenvolvimento de sistemas eólicos offshore no Brasil, partindo de pequenos projetos-piloto. Caso as propostas deste trabalho se tornem realizadas, os resultados para este país líder em energia limpa e renovável seriam: a criação de valor nas operações offshore de produção de energia fóssil, o ganho de aprendizagem sobre a tecnologia eólica, o alívio parcial da oferta energética para centros litorâneos no curto prazo; a racionalização do uso, transporte e dependência externa do gás natural; a dinamização dos Mecanismos de Desenvolvimento Limpo (CDM / MDL) e de novos mercados e empregos para a indústria. / In the last decade wind power source was the fastest-growing energy source. Technological learning curves for this sector fall down by a 15% a 20% rate each 3 years. Countries which are committed with wind power are running after the target of 12% wind into the worlds electrical production by 2020. The contribution of the offshore wind power (OWP) source is fundamental on covering such target, due to the proximity to load centers, efficiency & scale savings and reduced environmental and visual impact. Although the growth of the Brazilian power generation system in 2006, there is a gap on fulfilling demand in the short run. Nevertheless, Brazil has abundance of winds suitable for power generation, as a previous industrial framework, necessary on developing this sector. Even that a governmental program has come (PROINFA), wind power sector has not risen as expected yet. The goal of this thesis is to reinforce the debate about the importance on diversifying the Brazilian power matrix, towards the strategy of energy security supply as the reduction of greenhouse gases emissions. On reaching such a goal, this thesis states arguments by a generic approach and also by a specific approach. In the generic approach, it proposes a larger share for wind into the Brazilian electrical matrix as one of the options that should be considered in a more relevant manner for the tactics of diversifying the electrical matrix, following the example given by countries with larger abundance than Brazil regarding on natural gas production, as it is the case of the United Kingdom. In the specific approach, this investigation exemplifies possibilities of contributions from the OWP for the tactics of diversifying the matrix, following the example given by a country with higher predominance than Brazil regarding on using large hydropower as the main national power source, which is the case of Norway. The method taken for reaching the thesis goal involves the following steps: (1) to clarify on some aspects regarding energy production and its respective environmental problem related to the greenhouse gases emissions;(2) to clarify some aspects about the development of wind energy systems in Brazil and in the world and also some aspects about the development of OWP projects in selected countries; (3) to explore examples of articulation between OWP systems with offshore fossil energy production systems, in order to argue about the synergy that is possible between them; (4) to analyze and debate about the Brazilian governments proposal for the electrical matrix in the long run; (5) to propose some possibilities of developing OWP systems in Brazil, starting by small-scale pilot projects. If the case the propositions of this thesis come true in the future, the earnings for this country, which a world leader in clean & renewable energy, would be the following: value creation into the offshore fossil energy production; growth of learning about the OWP technologies; the partial relief of power supply for the coastal load centers; rationalization on the use, transport and foreign dependence of natural gas resources; pushing dynamics for Clean Development Mechanisms (CDM), as for industrial markets and employment.

Nas últimas décadas, a fonte eolielétrica é a que sinaliza maior crescimento mundial dentre as demais. A curva de aprendizagem tecnológica do setor mostra queda do custo entre 15% a 20% a cada 3 anos. Países ativos no setor eólico se esforçam pela meta de 12% de participação na produção elétrica mundial em 2020. A contribuição da geração eolielétrica offshore é fundamental para essa meta, pela proximidade aos centros de carga, com ganhos de eficiência, de escala e reduzido impacto ambiental e visual. Apesar do crescimento do parque gerador nacional em 2006, há carência na produção no curto prazo. Contraditoriamente, há ventos abundantes para geração eolielétrica e o prévio arcabouço industrial que seria necessário para desenvolver o setor. Apesar do incentivo governamental (PROINFA), o setor eólico brasileiro ainda não decolou como esperado. O objetivo deste trabalho é reforçar o debate sobre a importância da diversificação da matriz, em prol da estratégia de segurança do suprimento energético nacional e da redução da emissão de gases de efeito estufa. Em rumo a esse objetivo, são colocados argumentos com abordagem ampla e com abordagem específica. Na abordagem ampla, esta pesquisa propõe uma maior inserção da fonte eólica na matriz elétrica nacional como uma das opções a serem consideradas de maneira mais relevante nas táticas de diversificação da matriz, a exemplo do que já fazem países com maior abundância de gás natural que o Brasil, como o Reino Unido. Sob um ponto de vista específico, a investigação exemplifica possibilidades de contribuição da fonte eolielétrica, na sua versão offshore, para as táticas de diversificação da matriz nacional que se entendem importantes, a exemplo do já fazem países com maior predominância da fonte hidráulica que o Brasil, como a Noruega. O método utilizado para se alcançar o objetivo desta dissertação envolve os seguintes passos: (1) esclarecer quanto aos principais aspectos do setor energético a nível mundial e o problema ambiental que está vinculado à produção de energia por fontes fósseis; (2) esclarecer quanto aos aspectos do desenvolvimento de sistemas eolielétricos onshore no Brasil e no mundo e também do desenvolvimento de sistemas offshore em países de interesse; (3) explorar exemplos de articulação dos sistemas eólicos offshore com projetos de produção de energia fóssil em ambiente marítimo, como forma de produzir sinergia útil a ambos os setores; (4) analisar e debater sobre as propostas do governo brasileiro para o futuro da matriz elétrica do país; (5) propor algumas possibilidades de desenvolvimento de sistemas eólicos offshore no Brasil, partindo de pequenos projetos-piloto. Caso as propostas deste trabalho se tornem realizadas, os resultados para este país líder em energia limpa e renovável seriam: a criação de valor nas operações offshore de produção de energia fóssil, o ganho de aprendizagem sobre a tecnologia eólica, o alívio parcial da oferta energética para centros litorâneos no curto prazo; a racionalização do uso, transporte e dependência externa do gás natural; a dinamização dos Mecanismos de Desenvolvimento Limpo (CDM / MDL) e de novos mercados e empregos para a indústria. / In the last decade wind power source was the fastest-growing energy source. Technological learning curves for this sector fall down by a 15% a 20% rate each 3 years. Countries which are committed with wind power are running after the target of 12% wind into the worlds electrical production by 2020. The contribution of the offshore wind power (OWP) source is fundamental on covering such target, due to the proximity to load centers, efficiency & scale savings and reduced environmental and visual impact. Although the growth of the Brazilian power generation system in 2006, there is a gap on fulfilling demand in the short run. Nevertheless, Brazil has abundance of winds suitable for power generation, as a previous industrial framework, necessary on developing this sector. Even that a governmental program has come (PROINFA), wind power sector has not risen as expected yet. The goal of this thesis is to reinforce the debate about the importance on diversifying the Brazilian power matrix, towards the strategy of energy security supply as the reduction of greenhouse gases emissions. On reaching such a goal, this thesis states arguments by a generic approach and also by a specific approach. In the generic approach, it proposes a larger share for wind into the Brazilian electrical matrix as one of the options that should be considered in a more relevant manner for the tactics of diversifying the electrical matrix, following the example given by countries with larger abundance than Brazil regarding on natural gas production, as it is the case of the United Kingdom. In the specific approach, this investigation exemplifies possibilities of contributions from the OWP for the tactics of diversifying the matrix, following the example given by a country with higher predominance than Brazil regarding on using large hydropower as the main national power source, which is the case of Norway. The method taken for reaching the thesis goal involves the following steps: (1) to clarify on some aspects regarding energy production and its respective environmental problem related to the greenhouse gases emissions;(2) to clarify some aspects about the development of wind energy systems in Brazil and in the world and also some aspects about the development of OWP projects in selected countries; (3) to explore examples of articulation between OWP systems with offshore fossil energy production systems, in order to argue about the synergy that is possible between them; (4) to analyze and debate about the Brazilian governments proposal for the electrical matrix in the long run; (5) to propose some possibilities of developing OWP systems in Brazil, starting by small-scale pilot projects. If the case the propositions of this thesis come true in the future, the earnings for this country, which a world leader in clean & renewable energy, would be the following: value creation into the offshore fossil energy production; growth of learning about the OWP technologies; the partial relief of power supply for the coastal load centers; rationalization on the use, transport and foreign dependence of natural gas resources; pushing dynamics for Clean Development Mechanisms (CDM), as for industrial markets and employment.

Der vorliegende Beitrag entstand im Rahmen der Arbeiten von Teilprojekt C2 „Betreibungs- und Koordinierungsstrukturen“ im Sonderforschungsbereich 457. Die Forschungsarbeit des SFB 457 “Hierarchielose regionale Produktionsnetze“ fokussiert den visionären Ansatz einer kundenorientierten Vernetzung von Klein- und Kleinstunternehmen einer Region. Diese als Kompetenzzellen (KPZ) bezeichneten kleinsten nicht mehr sinnvoll teilbaren Leistungseinheiten kooperieren in hierarchielosen Produktionsnetzen und stellen sich auf diese Art und Weise dem globalen Wettbewerb.

Esta pesquisa apresenta como tema de estudo as Pequenas Centrais Hidrelétricas (PCHs). O seu objetivo geral é identificar os principais limites e potencialidades da sustentabilidade da cadeia produtiva de PCHs no Brasil, ao contexto das dimensões ambiental, social, econômica e institucional. O referencial teórico contempla conceitos e questões referentes: a cadeia produtiva; a Teoria do Ator-rede; as fontes de energia renováveis, mais especificamente a hidroeletricidade; e aos fatores determinantes da competitividade. Para a identificação dos gargalos e potencialidades, foi realizado um mapeamento da estrutura da cadeia de produção das PCHs, assim como a descrição do panorama atual das PCHs no país. Em seguida, foram estudadas, de forma mais aprofundada, cinco etapas que compõem a cadeia: recurso natural; geração; transmissão; distribuição; e comercialização. Na sequência, foram utilizados cinco critérios (importância, probabilidade, temporalidade, efeito e abrangência) para classificar os fatores identificados em cada etapa. Por fim, através da multiplicação dos índices numéricos atribuídos aos critérios, foi obtido o Índice de Significância (IS. No que tange à metodologia da pesquisa, ela pode ser classificada como aplicada e exploratória. Os dados empregados são secundários e foi utilizada a técnica de análise qualitativa. Como resultado, foram identificados 20 limites e 17 potencialidades relacionadas com a cadeia produtiva das PCHs no Brasil, sendo que destes 37 itens, 8 foram enquadrados como muito significativos, segundo os critérios estabelecidos para o IS. No que se refere ao resultado principal da pesquisa, verifica-se que, apesar de existirem potencialidades significativas para o desenvolvimento das PCHs na matriz energética nacional (o potencial hidrelétrico das bacias hidrográficas, a sua capacidade de atuar como vetor de desenvolvimento regional, a consolidação dos fabricantes de turbinas e geradores, e o livre acesso), alguns gargalos existentes na sua cadeia de produção devem ser trabalhados, tais como a interferência na migração e reprodução da ictiofauna continental, a desigualdade na distribuição de energia elétrica, e os aspectos legais e técnicos relacionados com o meio ambiente e a comercialização de energia. / This research study has as a theme: Small Hydro Power Plants (SHP). Its overall objective is to identify the main limits and potential sustainabilities of the productive chain of power plants in Brazil to the context of environmental, social, economic and institutional dimensions. The theoretical framework includes concepts that concern: the production chain, the Actor-Network Theory, renewable energy sources (specifically hydroelectricity) and the determinants of competitiveness. For the identification of limits and potential, mapping of the production of SHP chain structure was carried out; as well as the description of the current landscape of the SHP in the country. They were then studied in more depth. The five steps that make up the chain being: natural resource, generation, transmission, distribution and commercialization. Next, five criteria were used: importance, likelihood, timeliness, effect and scope; in order to classify the factors identified in each step. Finally, by multiplying the numerical index assigned to the criteria; the significance index (SI) was obtained, which was used to frame the final significance of the aspects by: less significant, significant and very significant. Regarding research methodology; it can be classified as: exploratory and applied. The data used was secondary and was used as qualitative analysis. As a result, we identified 20 potential limits and 17 related to the production chain of power plants in Brazil, and of these 37 items, 8 were classified as very significant, according to the criteria established for the IS. With regard to the main search result, it appears that, although there are significant potential for the development of SHP in the national energy matrix (hydropower potential of river basins, their ability to act as regional development vector, consolidation of turbines and generators manufacturers, and free access), some hurdles in the production chain must be worked out, such as interference in the migration and reproduction of continental fish fauna, inequality in the distribution of electricity, and the legal and technical aspects related to the environment and the commercialization of energy.

The dissertation uses the lens of electricity provision to examine processes of state formation in Somaliland, an unrecognized, self-declared independent state in the northwest of the former Somali Republic. The dissertation focuses on Hargeisa, the capital city at the heart of Somaliland's state-building project. After the collapse of the Somali state in 1991, private companies arose from the ruins of Hargeisa and turned the lights back on, navigating a fragmented post-war landscape by mobilizing local connections and transnational ties. However, being dependent on the political settlement that engendered the peace necessary for business, emerging private power providers were tied into a state-building project. The dissertation analyses the resulting tensions at the heart of this project, by examining the struggle to define the role, extents and limits of an emerging state in an interconnected world. Based on interviews in Somaliland and a survey of news media and grey literature, the dissertation has three aims. First, it provides a view into how social order and service provision persist after the collapse of the state. Secondly, it investigates how patterns of provision emerging in the absence of the state shape subsequent processes of state formation. Finally, it discusses how patterns of provision affect the interaction of state-building and market-making. In order to fulfil these aims, the dissertation examines how people invest in the project of building a state, both materially and discursively. The chapters present a narrative history of the electricity sector, explaining the attempts of both private companies and the government to claim sovereignty over the market and shape statehood in their own interests. The struggles shaping Somaliland's economic order reveal the contemporary significance of transnational connections, interconnected systems of capital flows, and the rise of corporate business actors. At the same time, they underline the abiding power of social structure, local identities, and historical memory.

CAPES / As variações de tensão de curta duração são perturbações típicas nos sistemas de distribuição de energia elétrica que afetam de forma significativa a qualidade da energia. Os equipamentos típicos para a regulação de tensão dispostos nas redes de distribuição em geral não são capazes de mitigar variações de tensão de curta duração. Entretanto, as unidades de geração distribuída conectadas aos sistemas de distribuição, considerando estratégias de controle adequadas, podem ser capazes de mitigar variações de tensão de curta duração nas proximidades do ponto de conexão. Nesse contexto, o presente trabalho propõe a mitigação de variações de tensão de curta duração a partir da utilização de unidades eólicas de geração baseadas em gerador síncrono de imã permanente (GSIP) conectado a rede por um conversor estático de potência. A mitigação das variações de tensão é feita por meio de uma malha de controle suplementar proposta aplicada ao controle tradicional do conversor do lado da rede. A estratégia de controle proposta explora a capacidade de operação em sobrecarga de corrente da unidade eólica e é capaz de mitigar variações de tensão de curta duração em sistemas de distribuição. A malha de controle suplementar proposta limita a geração de potência reativa na capacidade máxima de sobrecarga da unidade geradora, respeitando o limite térmico do conversor estático de energia. Além da malha de controle suplementar, uma metodologia baseada em estudos estáticos de fluxo de potência é proposta com o objetivo de avaliar a capacidade de regulação de tensão da geração eólica associada à malha de controle proposta. A capacidade da malha de controle proposta em mitigar as variações de tensão de curta duração é avaliada por meio de simulações não lineares no domínio do tempo envolvendo uma rede de distribuição com cargas concentradas. Diferentes níveis de inserção da geração eólica na rede de distribuição e outros fatores que impactam diretamente na regulação de tensão são considerados nos testes realizados. Os estudos realizados demonstram que utilização da estratégia de controle proposta aplicada a unidades eólicas de geração pode contribuir significativamente para a manutenção do perfil de tensão durante ocorrências de variações de tensão de curta duração. / The short duration voltage variations are typical disturbances that significantly affect the power quality in distribution systems. The typical devices for voltage support and regulation, distributed along the distribution networks, are generally not capable of mitigating short duration voltage variations. However, distributed generation units connected to the distribution system, when associated with suitable control strategies, can be able to mitigate short duration voltage variations. In this context, this paper proposes the mitigation of short duration voltage variations by using wind power generating units based on permanent magnet synchronous generator (PMSG) connected to the network by static power converter. The voltage variation mitigation is performed by means of a supplementary control loop added to the traditional control of the grid-side converter. The proposed control strategy takes advantage of the overload capability of the wind generation unit and it is able to mitigate short duration voltage variations in distribution systems. The proposed supplementary control loop limits the generated reactive power based on the overload capability of the generation unit, avoiding that the power electronic converter exceeds its thermal limit. Besides the proposed supplementary control loop, a methodology based on power flow studies is proposed in order to evaluate the voltage regulation capability of the wind generation associated with the proposed control loop. The performance and effectiveness of the control strategy proposed to mitigate short duration voltage variations is evaluated by means of time-domain non-linear simulations regarding a distribution network with lumped load. Different levels of integration of wind generation on the distribution network and other factors that directly impact on voltage regulation are considered in the tests. The performed evaluations have demonstrated that the proposed control strategy, applied to wind generation units, can significantly contribute to the maintenance of the voltage profile of distribution systems during the occurrence of short duration voltage variations.