Short-circuit power as important reliability factor for power system planning

Detailed stability analyses of a power system are performed at short-term and mid-term planning of transmission network development. At long-term planning, due to the uncertainty of power system data, the stability analyses are either omitted or performed in a simplified method. Currently, due to the economical and ecological reasons, the power system operators are interested to use the transmission network as close as possible to the thermal and stability limits. Therefore it is necessary to perform even a simplified power system stability assessment also at long-term planning. The paper shows that very simple criteria of angle and voltage stability based on short-circuit power can be used for the sake of long-term planning. The suggested criteria were verified for a real large-scale power system.