Inter-area stability prediction index based on phasorial measurement

In this paper it is proposed a real-time stability index based on the wide-area measurement made by PMUs. The proposed index can identify inter-area stability problems based on two parameters mainly: the voltage magnitude change (reduction), and the phase angle movement (separation). The most considerable feature of this index is its fast and easy calculation from synchronously measured voltage without system modelling and simulation and without dependency on network size. The results show that the behavior of the index with respect to the change in system stability is suitable. Additionally, a basic control of reactive power based on the index is implemented to show its applicability. Results show that the simplicity and easy calculation make this index very suitable for online application because severe contingences can be detected at the right time as well as blackouts can be prevented in advance when a control action is performed.