PowerGridModel
[IMPROVEMENT] ILSE performance improvement: Early exit for global angle only measurements
Describe the problem
Currently, in ILSE, each iteration "linearizes" the measurement to reach a converging solution. The algorithm currently should have exactly 2 iterations for a specific case of only-phasor measurements. (2 is minimum because we need to evaluate the exit criterion. For this condition exit criterion satisfies this way: $U_{iteration-2} - U_{iteration-1} = 0$.) This is because the linearization step does not occur in global angle measurement and both steps are the same.
This is because in the matrix formulation of ILSE:
- The LHS is same between consecutive iterations for all measurements.
- The RHS of ILSE equation is a function only of Y and z for phasor U, phasor I and zero injection measurements. While all other types of measurement introduce linearization which makes RHS a function of Y, z and U. This can be also be verified from the code.
Improvement proposal
We can then improve ILSE performance for this specific case with an early exit in the first iteration. The relative performance increment should be significant to make it worth the small effort.
We can make a flag only_global_angle_measurements flag available at the MeasuredValues stage and incorporate it in the iteration process for exit at end of 1st iteration.
