Theory 209/Power outages/Threshold lens
Cascades Need a Margin Threshold
The claim
Cascading failure occurs only where reserve margin falls below a threshold, so a well-margined grid absorbs the same fault.
01Mechanism
Overload requires the redistributed flow to exceed capacity somewhere; the threshold determines whether any element is vulnerable.
02Prediction
Cascades should track minimum margin.
03Refutation
Cascades tracking fault size would remove margin.