The reliability of the electrical power system supply requests often set up more sources. For a good design, a proper installation and operation, all the admissible sources sets and the related operating procedures have to be defined, including contingency conditions. The studies of the integrity procedures have to consider load flow and short circuits analysis . The clear evaluation of all the sources sets are a basic foundation for a safe and secure operation of the electrical installation. In the safety procedures, the re-energizing operation has to consider the feasible changed conditions of sources set. The Parise's Program introduces basic concepts and a logic method to plan the operating procedures, that would facilitate the design and the training by PC program also: it would offer a "string" to face the "labyrinth" of complex operating procedures