## CASTOR - positive margin stop criterion

#### Examples of use cases :

- For RCC - NTC Capacity calculation / Coordinated Security Analysis without costly remedial actions.

To calculate the maximum NTC, capacity calculation processes increase progressively the market exchanges (based on GLSK – Generation & Load Shift Key from TSOs). As long as CASTOR finds a solution where its objective function is positive or null, it means there is a set of remedial actions that avoids all violations of operational limits on CNECs.

Max NTC is the last and highest value of market exchanges where the objective function is positive.

Where required by methodologies approved, sequential optimisation of non-costly remedial actions (CASTOR « positive margin ») and costly remedial actions (FARAO closed optimisation) is possible.

- For TSOs - Local validation of 70% margin required by Regulation EU 2019/943, Article 8 (Clean Energy Package). This allows TSOs to perform an optimised security analysis in order to confirm the operational feasibility of 70% margin.