This master thesis examines technical requirements for small hydro power plants (HPP) to operate proximate parts of the power grid in island mode. The work examines how small hydropower can be modified and complemented with additional technologies to achieve sufficient frequency control capabilities. A case study was performed within the concession area of power grid operator Ålem Energy. One of the HPPs, located in Skälleryd, is owned by Ålem Energy and became the focal point of the study. Relevant parts of the concession area were surveyed for properties such as system inertia, electric load and available power. Furthermore, a model of Kaplan turbine 1 in Skälleryd HPP was created with the purpose of studying the benefits of bypassing regulation control from the wicket gates directly to the runner. The method was tested in an off-grid islanding test. Frequency control of the turbine was tested powering electric heaters and, using a new method, controlling a virtual power grid. Finally, a theory was developed to estimate the transient disturbance resilience (TDR) of a power grid. The theory was applied to the HPP in Skälleryd to suggest modifications for the plant to achieve sufficient islanding capabilities. The survey of the power system revealed a promising potential for the HPPs to operate in island mode, especially at later stages when the grid spans several HPPs for more system inertia. The available power from the HPPs was however strongly seasonal which imposes flexibility on a future plan of action for engaging the grid in island mode. The method of controlling the turbine power from the runner proved to have several difficulties. Firstly, the current hydraulics system was not able to freely control the runner as the hydrodynamic forces on the runner blades were too large. Secondly, the method was found to be unstable due to inherent amplification of speed deviations. Furthermore, the low inertia at Skälleryd is likely detrimental to the lone frequency control of the turbine. Therefore other methods for improving frequency control were suggested. The developed theory for TDR was used to create charts describing the TDR for various combinations of system inertia and regulation speed. By studying the proprieties of Skälleryd HPP in the charts the necessary modifications could be rationally chosen. A frequency regulating dummy load was found to be the simplest option. A control scheme was suggested with the dummy load performing primary frequency control and the turbines at Skälleryd performing secondary control, restoring the dummy load to its nominal state.

This study investigates the situation of Rwandan youth ex-combatants in the Democratic Republic of Congo (DRC). Specifically, the study examines how and why young people become involved in conflicts as fighters, how the conflict impacts upon them, and how the Disarmament, Demobilization, Rehabilitation and Reintegration programs set up by international aid agencies attempted to address the youth's special needs as they relate to reintegration in their home communities. By employing qualitative semi-structured interviews and group discussions with demobilized ex-combatant youth and other stakeholders in northern Rwanda, the study examines how the Western model and assumption of childhood and child soldiering has so far dictated the approaches of international aid agencies in response to the needs of young people in armed conflicts. The study challenges some of the assumptions and argues for a more representative and focussed approach that emphasizes on the socio-cultural context of the ex-combatants. The research shows how and why some youth voluntarily join armed groups. It also highlights the resilience of the youth in the midst of conflict and their ability to rebuild their lives. The findings of the research have some implications for the way the international aid agencies conceptualize and provide assistance to the young people affected by armed conflicts. It challenges the assumption held by the aid agencies regarding the exclusive emphases on victimization and trauma counselling, and refocuses on the need to rebuild the youth's resilience and coping strategies. / Sociology / MA (Sociology)

This study investigates the situation of Rwandan youth ex-combatants in the Democratic Republic of Congo (DRC). Specifically, the study examines how and why young people become involved in conflicts as fighters, how the conflict impacts upon them, and how the Disarmament, Demobilization, Rehabilitation and Reintegration programs set up by international aid agencies attempted to address the youth's special needs as they relate to reintegration in their home communities. By employing qualitative semi-structured interviews and group discussions with demobilized ex-combatant youth and other stakeholders in northern Rwanda, the study examines how the Western model and assumption of childhood and child soldiering has so far dictated the approaches of international aid agencies in response to the needs of young people in armed conflicts. The study challenges some of the assumptions and argues for a more representative and focussed approach that emphasizes on the socio-cultural context of the ex-combatants. The research shows how and why some youth voluntarily join armed groups. It also highlights the resilience of the youth in the midst of conflict and their ability to rebuild their lives. The findings of the research have some implications for the way the international aid agencies conceptualize and provide assistance to the young people affected by armed conflicts. It challenges the assumption held by the aid agencies regarding the exclusive emphases on victimization and trauma counselling, and refocuses on the need to rebuild the youth's resilience and coping strategies. / Sociology / MA (Sociology)