The grid code, FIKS, from the Norwegian transmission system operator (TSO), Statnett, states that synchronous generators > 25MVA, must have a static excitation system. However, an improved brushless excitation system is in operation on some commercial power plants (36MVA, 93.75rpm & 52MVA, 166.67rpm) with grid-assisting performance beyond the conventional static system. The convenional diode bridge is replaced with a remote-controlled thyristor bridge on the shaft. If wireless communication is not allowed, a control signal through brushes should be employed instead. The thesis explores the expected new era for large brushless hydrogenerators. The proposed brushless system have benefits of reduced regular maintenance due to elimination of brushes and reduced unscheduled maintenance due to redundancy; causing a redused cost-of-energy. A six-phase exciter design with a hybrid-mode thyristor bridge interface leads to improved fault-tolerance, better controllability, minimized torque pulsations and reduced armature currents of the exciter. Excitation boosting (EB) capability is included in the brushless system without additional components or circuitry, contrary to the static excitation system. The brushless excitation system is made insensitive to voltage dips in the interconnected grid, causing improved fault ride-through (FRT) capability and power system stabilizer (PSS) actions.

Insourcing, outsourcing and co-sourcing are three approaches to procuring an information system. This research contributes to the body of knowledge on insourcing an information system; exploring and discussing the enabling and inhibiting factors of the insourcing of an information system in selected government agencies in Malaysia. This study was undertaken in response to a paucity of similar projects and a limited literature focused on developing countries. It considers the post outsourcing context following the decision to insource a major Malaysian Government Information System in 2011. A qualitative research method was used to obtain empirical evidence from selected government agencies through 69 semi-structured interviews in two data collection periods: 2013-2014 and 2015. Interviews were conducted with civil servants at all levels, from senior management to clerical staff, including users of the government information system. By using coding principles from grounded theory to analyse the data, seven exciters and six inhibitors of insourcing a government information system were identified and mapped in the analytical framework. Further, this is the first research to use an enhanced model, devised by combining the OPTIMISM model and two distinct theoretical traditions: institutional theory and the capability approach; in order to analyse the insourcing of government information system adoption. The enhanced model was created by mapping the OPTIMISM model (that has a set of dimensions) to an analytical framework comprising the capability approach, institutional theory and technology (ICTs). The main research contribution of this thesis is in the area of capacity building of the internal development team. The increased budget for training, the selection of appropriate training providers and knowledge sharing among experienced and novice developers all contribute to building capacity in the internal development team; and consequently help to improve the quality of the system which will improve service delivery to the general public. The approach and findings of this study contribute to the body of knowledge and understanding of the subject in government information system development and implementation, and can also be applied to improving the quality of service delivery. While this study has focused on government information systems, the wider area of eGovernment, and applications serving the needs of the general public, is equally important, and therefore the researcher suggests that insourcing eGovernment applications would also assist in the capacity building of internal IT staff.

Orientador: Michael John Brennan / Resumo: Vazamentos em tubulações de água enterradas são considerados um importante problema já que uma grande quantidade de água é desperdiçada entre a planta de tratamento e os consumidores. Para lidar com tal problema, companhias de saneamento utilizam dispostivos para localizar vazamentos nas tubulações. Dispositivos de escuta e correlacionadores de ruídos são os equipamentos mais utilizados em campo pelas companhias de sanemaneto ao redor do mundo. Correlacionadores de ruídos são dispositivos usados na localização de vazamentos em tubulações enterradas através da estimativa do tempo de atraso entre os sinais medidos pelos sensores posicionados em ambos os lados de um suposto vazamento. Uma vez que as companhias de saneamento devem decidir qual tipo de correlacionador é o mais compatível com a sua rede de tubulações, elas devem realizar alguns testes para ajudar em tal decisão e para treinar os funcionários que operam estes dispositivos, os quais devem ser expostos a diferentes condições, tais como tubos de diferentes materiais e geometrias, diferentes tipos de solo, vazamentos com diferentes intensidades, etc. Neste contexto, o principal objetivo desta pesquisa é contribuir com esta necessidade através da elaboração de um dispositivo de bancada capaz de reproduzir as vibrações de um tubo causadas por um vazamento. O dispositivo, chamado de simulador virtual de vazamentos, é composto por um computador, um amplificador de potência com dois canais e dois shakers. Ruídos de vazamento... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Leakage in buried water pipes is an important problem since a large amount of water is wasted between the treatment plant and the consumers. To deal with such a problem, water companies have used some devices to localize leaks in the pipe network. Listening devices and leak noise correlators are the most popular equipment used in the field by the water companies around the world. Leak noise correlators are important devices used to localize leaks in buried pipes by calculating the time delay between the signals measured by the sensors positioned either side of a suspected leak. Since water companies have to decide which leak noise correlator is more suitable for each pipe network, they have to carry out some field tests to assist in this decision and to train the personnel that handles such a device, which ideally must be exposed to different conditions, such as pipes with different materials and geometries, different types of soil, different leak strengths, etc. The main objective of this research project is to contribute with the necessity of the water companies by designing an indoor bench-top device capable to reproduce the pipe vibrations generated by a leak in the field. The device, called virtual pipe test rig, comprises a computer and a dual-channel power amplifier supplying two shakers. In the computer, leak noise is synthesized by using a model of a buried leaking pipe implemented using the software Matlab®. Since the systems, composed by the power amplifiers and th... (Complete abstract click electronic access below) / Mestre