This paper describes the use of modal analysis in electromagnetic transient studies of ac networks having long transmission lines. Modal analysis provides structural information on the system and nicely complements the results from conventional time and frequency response simulations. Results of energization studies on a small test system, having a long transmission line, are included. The simulations obtained from modal analysis were compared with those produced by a conventional electromagnetic transients program, showing good agreement. The modal analysis methodology may lead to more efficient computation in parametric studies, as shown in the paper.