  Water and power systems are increasingly interdependent due to the growing
number of electricity-driven water facilities. The security of one system can
be affected by a contingency in the other system. This paper investigates a
security-constrained operation problem of the energy-water nexus (EWN), which
is a computationally challenging optimization problem due to the nonlinearity,
nonconvexity, and size. We propose a two-step iterative contingency filtering
method based on the feasibility and rating of the contingencies to decrease the
size of the problem. The optimal power and water flow are obtained in a normal
situation by considering the set of contingencies that can not be controlled
with corrective actions. The feasibility check of the contingencies is
performed in the second step, followed by a rating of the uncontrollable
contingencies. Finally, the critical contingencies are obtained and added to
the first step for the next iteration. We also employ convex technologies to
reduce the computation burden. The proposed method is validated via two case
studies. Results indicate that this approach can efficiently attain optimal
values.
