THE increase of stochastic renewable infeeds to transmission networks as bulk generation of large offshore windfarms or as distributed generation in distribution networks requires new strategies in the system operation. On one hand the transmission capacity of the power systems must be as high, as unplanned dynamics, caused by these infeeds, can be transported without producing system bottlenecks. Such dynamic energy transports occur sometimes over long distances and require operational coordination between different TSOs. On the other hand new indicators, describing the power system stability and the margins to stability limits must be developed and tested, which allow a prediction of the dynamic state of the power system if contingencies would occur.