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Sulphur hexafluoride gas is the dominant insulation and interruption material in high voltage gas insulated substation. Its usage remains a concern of transmission system operators owing to the global warming potential of the gas. The work carried out in this thesis aims to find the environment-friendly materials that can replace SF6. These candidates are required to have a strong dielectric strength for high voltage busbar insulation and well arc extinguishing capability necessary for high voltage circuit breaker.A range of alternative insulation types including CF3I gas and its mixture, high pressure air and solid insulating foam are considered as substitute of SF6. Theoretical studies on the dimensions of busbars used in substations are carried out for these options. The dimension of the dielectric system and its ampacity of respect system are calculated using heat transfer models considering their boiling point and proper working pressure which is related with the dielectric strength of some gas.On the other hand, SF6 gas circuit breaker is extremely popular on the medium and high voltage power networks owning to its effective arc extinguishing performance. It would be ideal if a substitute material could be found for SF6 as an interruption material. Biodegradable oil PTFE ablation, other gas candidates including N2, CF3I are investigated as possible replacement of SF6 through literature study.The usage of vacuum circuit breaker is eventually capable to operate in high voltage transmission system. Simulations have been carried out with software ATP/EMTP to investigate the influence of different characteristics of vacuum circuit breaker including chopping current level, the dielectric strength of vacuum gap and the opening time. And then the probability of overvoltages when vacuum circuit breakers installed is studied by statistical study in MATLAB.

The diploma thesis deals with the optimization of powder-coating process resulting in a reduction of labor intensity during finishing components in gas insulated switchgear (GIS). The thesis is divided into five main chapters that describe characteristic and function of gas insulated switchgear (GIS), the theory of powder-coating, including mechanical and chemical pretreatment of surfaces, the studies of contemporary quality of coating process in the company ABB s.r.o. with classification of components of GIS according to their function. This chapter also contains detailed analysis of section of coating process during the processing of selected parts (housing and conductor). The thesis also contains detailed studies of masking of surfaces at coating parts, specifies the most common defects and determines the main cause presented in a well-arranged chart, design, description and realization of optimization solutions with selection and evaluation of final version. An economic comparison of contemporary condition of powder-coating process with designed optimization solution is stated at the end of the thesis.

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This work is focused on the measurement of partial discharges in gas insulated conductors manufactured by ABB. The theoretical part contains the definition of partial discharges, their analysis and detection methods. It also deals with the general description of gas-insulated substations and then with the concrete components manufactured at ABB in the Brno-Slatina production plant. The practical part describes the course of measurement, definition of the main problems and their explanation. The output from the practical part is a measurement library with given characteristics, which show the location and character of the problem in detecting partial discharge in a given encapsulated assembly.

Svenska kraftnät is responsible for the operation and development of the Swedish transmission grid. A large number of substations in the transmission grid are approaching their expected service lifetime and must be renewed in the coming years. When renewing substations, total and partial outages in operation are often unavoidable. These outages may cause downtime for any party connected to the substation, whether it be an electricity generation or consumption. A solution is to build a new substation while the old is still in operation. Upon completion, a transfer of operation can be done from the old to the new substation. This however requires laying claim to new land, which affects the local environment and can be a time-consuming process. In an effort to minimise the need for planned outages during substation renewals, Svenska kraftnät wants to investigate techniques for bypassing substations while also allowing the connected party to remain in operation. This thesis has evaluated two differing techniques that allow for substations and any connecting parties to remain mostly in full operation during station renewals. One technique involves constructing a temporary switchgear compartment using air-insulated apparatuses to bypass the station and connect the third party. The other technique uses a mobile gas-insulated switchgear to achieve essentially the same arrangement.  After studying cases where either technique has been employed in station renewals, it was concluded that a solution utilising air-insulated apparatuses is better in several aspects. While the two technologies achieved similar results, the air-insulated technology did so at a lower cost, offered more flexibility, and was easier to integrate into pre-existing stations. Furthermore, the gas-insulated technology required more specialised competence, possibly limiting the availability of qualified contractors. It was concluded that bypassing stations during renewal projects could provide several benefits in terms of less downtime and economical losses, while also minimising the need to claim new land. In order to optimise the method a supply of air-insulated apparatuses and construction materials necessary for the bypassing of a station should be established by Svenska kraftnät. This, mostly reusable, equipment would then be on stand-by, ready to use in future station renewals.

This thesis deals with the design of gas insulated switchgear produced in company ABB s.r.o. Theoretically describes the basics of project engineering in the 2D and 3D environments as well as the construction, partition and properties of the switchgear substations. In thesis is included practical designs and comparison of a gas insulated switchgear draft in 2D and 3D interface in the offer phase.