Real-time transient stability emergency control of the South-Southeast Brazilian system

A method is proposed for during transients emergency control which predicts the evolution of a system undergoing a major disturbance and, if loss of synchronism is anticipated decides control actions able to contain it. The method emanates from SIME, a hybrid time-domain direct method originally designed for realtime preventive transient stability assessment and control. The devised “emergency SIME” has similar interesting features, namely, robustness, accuracy, speed - and also predictive capabilities. Besides, the emergency approach has some intrinsic advantages over the “preventive” approach, namely, it is free from modelling and/or parameter uncertainties (since it relies on real-time measurements rather than time-domain simulations), and it encounters the real stability problem (operating point and contingency scenario rather than base case solutions and list of plausible contingencies). The method is general with respect to power system configurations, types of generation and of controls. In this paper a generation shedding scheme is worked out and applied to the real-time monitoring of the Itaipu-Foz do Igua¸cu corridor. It is shown that it can advantageously complement the existing automatic
emergency control scheme.