Modelling of Black Start and Island Grid Operation with Deflector Controlled Pelton Units

Events as the Italy blackout 2003 and the grid splitting 2006 brought up grid restoration and black-start ability as an urgent topic for both grid and power plant operators. Measures for preventing and handling such scenarios have been developed by several national system operators and were harmonised by the ENTSO-E 'Network Code on Emergency and Restoration', which entered into force on 18.12.2017. In this context large scale black start and grid restoration test are conducted in the southern Austrian power grid of Carinthia by the grid operators Kärnten Netz GmbH (KNG) and Austrian Power Grid (APG) in collaboration with the power plant operators Kärntner Elektrizitätsaktiengesellschaft (KELAG) and Verbund Hydro Power (VHP). The latest tests in 2017 were focused on one hand on the improvements of frequency stability by the utilization of additional inertia and the implementation of a deflector based power control for one Pelton unit and on the other hand on the re-synchronisation of independent island grids. The obtained data is used to develop and validate a simple, but accurate in terms of frequency reaction, model of the speed controller of a deflector controlled Pelton unit in the simulation Software DigSilent PowerFactory. The validated model is further used to investigate different combinations of generator commitment and controller configurations in a network area with several power plants as a use case.