Real-time identification and monitoring of the voltage stability margin in electric power transmission systems using synchronized phasor measurements

In this thesis, the PMUs are turned to useful sources of real‐time data. They provided the required information needed by the grid operator on the actual system state and are combined with relevant data of the given system with the aim to early detect impending voltage instability. Furthermore the data are used to define the minimal voltage stability margin i.e. how far a given system operating state is from a state where voltage instability will occur. Thereby, a statement on the actual system operating state is made on the base of the actual active load transfer on each individual transmission line of the grid section considered.