This diploma thesis presents managing of the island mode using distributed generation. In the theoretical part of the thesis, the power system of the Czech Republic is described, together with its future development, and future development of installed capacity of distributed generation. Types of distributed generation are also mentioned. Next part of this work is focused on technological parts of islanding operation and its requirements. The following part describes components of the smart grids and mentions some of its functionalities. The practical part of the thesis describes the created models of components in PSCAD programme. From those components two slightly different grid models are created. On those grid models, simulations are made, during which island mode is created. Some of the grid functionalities are tested during those simulations, for example; reaction of the island mode for load increase, load decrease and others.

This work deals with the issue of supply restoring for heating plant Teplárny Brno, a. s. Špitálka division, after a system-wide failure of the “blackout”. The thesis solves the “black start” of the Špitálka Teplárny Brno operation by delivering a voltage from the hydroelectric power Vír I, proposes a methodology for commissioning of individual devices, up to phasing the generators with subsequent possibility of creating an “island mode” in the area of Brno city, which the work already does not deal with. The work also deals with the preparation of the operational test, while starts of the selected devices are tested. The schedule of commissioning of each device is supported by calculations of the parameters for the entire system with regard to voltage drops while connecting the high load. The result of this work is the proposal of methodological process of supply restoring for power plant Teplárny Brno – Špitálka division, by submission a voltage from the hydroelectric power Vír I, which can be used both in any system-wide failure of the “blackout”, or during the operational test.

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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.