Compute generator remaining margin depending on change direction

[vmouradian]

Describe the current behavior

In active power distribution, when compution participation factor of a generator with PROPORTIONAL_TO_GENERATION_REMAINING_MARGIN. The participation factor is proportional to max(0, maxP - targetP), even if the distribution should reduce targetP.

Describe the expected behavior

Use max(0, maxP - targetP) if the mismatch to distribute is positive, and max(0, targetP - minP) if mismatch is negative.

Describe the motivation

Customer request. (+ is more consistent)

Extra Information

No response