What is N-1 contingency analysis and how is it performed?

N-1 contingency analysis tests system security by simulating loss of each single element (line, transformer, generator) and checking that no violations occur. The process involves: building base case power flow, creating contingency list, simulating each contingency, solving post-contingency power flow, and checking for thermal overloads, voltage violations, and stability issues. Results identify critical contingencies requiring remedial action. N-2 analysis considers double contingencies. Automated tools screen thousands of contingencies quickly.