  This letter concerns optimal power transmission line inspection formulated as
a proposed generalization of the traveling salesman problem for a multi-route
one-depot scenario. The problem is formulated for an inspection vehicle with a
limited travel budget. Therefore, the solution can be composed of multiple runs
to provide full coverage of the given power lines. Besides, the solution
indicates how many vehicles can perform the inspection in a single run. The
optimal solution of the problem is solved by the proposed Integer Linear
Programming (ILP) formulation, which is, however, very computationally
demanding. Therefore, the computational requirements are addressed by the
combinatorial metaheuristic. The employed greedy randomized adaptive search
procedure is significantly less demanding while providing competitive solutions
and scales better with the problem size than the ILP-based approach. The
proposed formulation and algorithms are demonstrated in a real-world scenario
to inspect power line segments at the electrical substation.
