Reduce irrealistic voltage created by remote voltage control

[vidaldid-rte]

Describe the current behavior

Remote voltage control is implemented by a QPV algorithm.
The controlled bus is QPV. THe controller is P only.
The equations expects that the controller delivers enough active power to the controlled bus to maintain the target voltage.
AN outerloop moves the controller to Q status if the injections is out of its reactive limits.

But mechanically, this modifies that voltage of the controller bus - sometimes below the realistiv controls
Sometimes also, because the controllers voltage is a quadratic function of Q at the other end of al line, Q min is never reached at the conroller bus even with very low Q delivered at controlled bus.

Describe the expected behavior

When voltage targets are not too irrealistic do not produce irrealistic voltage at the stator.

Note: the method can not protect againts completelly irrealistic voltage targets that can create divergence (imposible to find a configuration hat keep the volrage at controller bus) or produce negative voltage at controller bus and LU factorisation issues.
For irrealisti voltage targets, that method should be used in combination with an incorrect voltage target detector such as #1115

Describe the steps

Proposed solution:

• If ReactiveControlLimit outerloop is used:
• deactivate irrealistic voltage control until ReactoveLimitOuterLoop is stable (idea similar to Add an option that allow checking unrealistic voltage only on final state of the loadflow. #1087)
• in ReactiveLimitOuterloop set the remote controller bus with irrealistiv voltage to PQ and Qmin/Qmax. Reset their voltage to 1.

Environment

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Relevant Log Output

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Extra Information

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