| name | thermal-overload-mitigation |
| description | Senior power-engineer playbook for overloaded lines and transformers. Use whenever power-flow or contingency studies show loading above ratings — including escalations from a tool skill where branch loading exceeds 100% of its rating. Triggers on "line overloaded", "transformer above rating", "relieve congestion", or "redispatch to unload". Gives an operationally credible sequence of redispatch, topology, phase-shifter, and reinforcement actions rather than only flagging the overload. |
Thermal overload mitigation
Start with the monitored element, the applicable rating, and the driving condition.
Preferred action order
- Confirm the overload is real: correct rating set, correct outage state, and solved base case or contingency.
- Redispatch generation or transfer patterns to unload the corridor.
- Reconfigure topology or switching where operations permit.
- Use phase shifters, HVDC schedules, or transformer controls only when sensitivity evidence supports them.
- If the issue is persistent, move to reconductoring, uprating, or new facilities.
- After each action, re-solve and confirm the overload is relieved. If it is not, continue to the next step.
Worked example
Line A-B sits at 105% of its normal rating after the N-1 loss of Line C-D. The PTDF for a
G3-to-G5 transfer on Line A-B is -0.18 MW/MW, so shifting 40 MW off G3 onto G5 unloads
A-B by about 7 MW, bringing it to 94%. Re-solving the full monitored contingency set
confirms the redispatch creates no new violations elsewhere.
Working rules
- Separate normal-rating issues from emergency-rating issues.
- Fix the smallest set of elements that relieve the monitored overload cluster.
- Validate a candidate fix on all critical monitored contingencies, not just the worst case.
- Use PTDF or LODF style sensitivities when the software provides them.
Deliver
- The overloaded elements and rating basis.
- The dispatch or topology changes that help most.
- The recommended corrective action and the residual risk.
