Good question. Are you talking about generation, transmission or distribution?
From my experience as an electrical engineer working for a distribution network:
* The traditional approach to network planning: take your edge cases (e.g. winter peak demand), and apply your engineering knowledge and intuition to manually study the most onerous outage conditions.
* This will vary on where you are in the world, but networks tend to have a good amount of slack built in.
* As networks become more complex, and the cost of computing has fallen, it's more feasible to automate contingency analysis (think about the number of different outage combinations for an N-2 scenario).
FWIW, the internal tools that I work on makes use of networkx to determine contingency cases.
~20 years ago, the regulator introduced an incentive scheme to reduce customer interruptions and minutes lost. This resulted in heavy investment in network automation in the UK.
From my experience as an electrical engineer working for a distribution network:
* The traditional approach to network planning: take your edge cases (e.g. winter peak demand), and apply your engineering knowledge and intuition to manually study the most onerous outage conditions.
* This will vary on where you are in the world, but networks tend to have a good amount of slack built in.
* As networks become more complex, and the cost of computing has fallen, it's more feasible to automate contingency analysis (think about the number of different outage combinations for an N-2 scenario).
FWIW, the internal tools that I work on makes use of networkx to determine contingency cases.