Features and Improvements
- Oneline Diagrams: Added an option to show Line Shunts on Branches, Transformers and Series Caps. If the branch has 2 segment or less the Line Shunt will be placed in the middle of the segment.
* If the branch has 3 or more segment the line shunt will be placed at the end of the segment in the From Bus and the start of the last segment in the To Bus.
* If the branch has 1 segment then line shunts will be placed at 10% and 90% of the segment.
* If the branch has 1 segment the size of the Line Shunt will be 10% of the segment, and if the branch has more than 1 segment the size of the Line Shunt will be 0.25% of the line segment. The width of the Line Shunt will be half the length of the line shunt.
* If the Line Shunt MVARs total is greater than 0 the line shunt will display a capacitor symbol and if the line shunt total is less then 0 it will show a reactor. Zero total MVARs will result in no line shunt shown on the branch. - Optimal Power Flow (OPF): For constraints that have both upper (positive) and lower (negative) limits in the OPF/SCOPF, the Lagrange multipliers for each constraint, Lambda values being displayed in the user-interface and returned through AUX script or data sections were the absolute value of the actual Lambda value calculated by the Simplex linear program. In keeping with the convention that the Lambda for each constraint is the incremental price for increasing the flow on that constraint by 1 unit, both positive and negative Lambda are meaningful. A Lambda of zero means that the constraint is within limits, and a non-zero lambda means at or exceeding limits. So if an interface A is at +250 MW and is exceeding a +234 MW positive limit, then the marginal price is +1000. When an interface B is at -150 MW (since it was monitored in both directions) and is exceeding a -123 MW negative limit, then the marginal price is -1000. Increasing flow by 1 MW on interface B (from -150 to -149), will incur a price of -1000, because increasing by 1 MW lessens the degree of violation, hence a reduction of 1000 in price. the values reported as the marginal cost reported for lines, interfaces, etc are now consistent with this.
- Security Constrained OPF (SCOPF) Tool: Contributions to bus MW Marginal Cost from contingency interface constraints was wrong due to a sign error. This has been corrected.
- Security Constrained OPF (SCOPF) Tool: The loops in the DC and AC SCOPF were slightly different with respect to the criteria to continue including more contingency violations into the LP simplex tableau. In AC SCOPF, having both the tableau constraints within the tolerance and having no further control changes would no longer include new contingency violations into the tableau -- the idea being, with the worst violations already included, there was no additional control range available to make a difference to the remaining contingency violations that were not included. In contrast to this, in the DC SCOPF having the tableau constraints within the tolerance was being checked, but having no further control changes was not being checked. This would result in many more constraints to be included in the tableau, but all those gave insignificant control changes. The DC SCOPF termination logic has now been changed to match that of the AC SCOPF. The AC and DC SCOPF dispatches would be the same as before, The improvement comes in the explainability of the results shown in the contingency violation table that would now be commensurable across both DC and AC SCOPF methods.