Here is a detailed description of how the angle monitoring algorithm operates:

• Apply optimal preventive remedial actions from RaoResult on the network

• From the CRAC, get the set of states on which AngleCnecs exist

• For each of these states, monitor angles:

  • Use a new copy of the network

  • If the state is not preventive,

    • apply the contingency on the network

    • from the RaoResult, apply on the network the optimal remedial actions decided by the RAO (automatic and curative)

  • Compute load-flow

    • If it diverges, return the following content for this state, then move on to the next state:

      • the angles of the angle CNECs equal to NaN

      • no applied remedial actions

      • status DIVERGENT

  • Compute the angles for all angle CNECs, as the maximum phase difference between the 2 voltage levels (1)

    • Angle in degrees = 180 / pi * (max(angle on buses of exporting voltage level) - min(angle on buses of importing voltage level))

  • Compare the angles to their thresholds. For the AngleCnecs that have an angle overshoot, get the associated remedial actions (2)

    • If the AngleCnec has no associated RA, then the angle constraint cannot be remedied: move on to the next AngleCnec.

    • If the state is preventive, do not apply any PRA (it would be incoherent with the RAO results). Move on to the next state.

    • For every RA:

      • If the remedial action is not a network action, do not apply it (if it’s a RangeAction, we cannot know which set-point to use). Move on to the next RA.

      • If the RA is a network action, apply it on the network.

  • If any injection-set-point RA was applied, create and apply the re-dispatch that shall compensate the loss of generation / load (3):

    • The amount of power to re-dispatch is the net sum (generation - load) of power generations & loads affected by the RAs, before changing the set-points

    • The GLSK to use shall be the same as the one used for the whole process

    • Exclude from the re-dispatching all the generators & loads that were modified by an injection-set-point RA, since they should not be affected

  • If any RA was applied, recompute the load-flow

    • If it diverges, return the following content for this state, then move on to the next state:

      • the angles of the AngleCnecs equal to what was computed in step (1)

      • no applied remedial actions

      • security DIVERGENT

  • Re-compute all angle values (4)

  • Create an intermediary result, with angles computed in (4), list of applied remedial actions in (2), and secure flag set to SECURE if there is no more overshoot (after re-verifying thresholds)

• Assemble all the state-specific result in one overall result and update the RAO result object