Real-Time Stability Monitoring at Transelectrica

This paper describes the approach taken by Transelectrica S.A. to real-time stability assessment. Seamlessly integrated with the real-time network analysis sequence is a fast voltage and steady-state stability application that runs automatically after each successful state estimate. The calculations are performed both for the entire interconnected system of Romania and for the areas connected via "stability constrained links". The "stability constrained links" are transmission paths where the stability limits are more restrictive than the thermal limits. They are identified via off-line studies and are dynamically reconfigurable. The key results are posted on intuitive diagrams, including a real-time stability trending chart, which allow the operator to continuously monitor the distance to instability both on a system level and across critical area interfaces. This is a first, and very efficient, line of defense against blackouts. The next step consists of periodically evaluating what-if scenarios with comprehensive off-line stability tools