Introduction: The pan European transmission grid will have to be re engineered progressively in order to accompany the electric system decarbonisation, shaped by a first set of intermediate targets in 2020. This long term transition will make transmission networks more and more complex with impacts on normal and emergency operations.

• Much larger power transfers over longer distances

• Predicting accurately the scheduling of power plants across Europe will become more difficult, which, in turn, will require conventional generators to balance the whole system

• With the rapidly increasing penetration of renewable electricity generation and the difficulty to build new overhead power lines, each TSO in Europe will no longer be able to comply with the classical preventive N-1 security standards all year round

• When operating a power system close to its stability limits, unstable dynamic phenomena may appear after a contingency. The standard static security assessment based on power flow calculations is not anymore sufficient.

Overall, transmission operators take margins (limits below the true physical limits) in their day-to-day decision making process, which allows ensuring system security. The pan European system will be more and more stressed. It will become less and less possible to keep such margins safe. An improved assessment of the limits and of the distance to these limits is a prerequisite to avoid considering the system as unsafe and uncontrollable, even in ‘normal’ operating conditions.

Objectives: With increasingly complicated grid studies, new techniques will be required to enable the operation of the transmission system. This project aims to provide these initial studies and develop operational practice that can be used across the Europeans Operators.