Robust Signals for the TCSC Oscillation Damping Controllers of the Brazilian North-South Interconnection Considering Multiple Power Flow Scenarios and External Disturbances

The POD signals implemented in the existing thyristor controlled series compensators (TCSCs) of the Brazilian north-south (NS) interconnection are solely intended to damp the low-frequency NS oscillation mode. These signals are derived from the modulus of the active power flow in the NS line that is phase-lagged at the frequency of the NS mode and experience relatively large excursions following exogenous disturbances. This paper attempts deriving the POD signal from the same variable but with a different polarity and employing phase-lead compensation. A notch filter is also used to further reduce the adverse transients in the POD control loop, lowering the risk of TCSC saturation. The described results relate to a large-scale model for the year 1999, considering seventeen power flow scenarios and used by a multi-utility task force involved, at the time, in the planning studies of this interconnection.