**8. Conclusions**

The paper is the result of basic research in the field of operational research and maintenance management, with contributions and applications in optimization strategies of RCM for EDS. The contributions refer to the formulation the mathematical models of preventive maintenance strategies belonging to RCM, solving technical and economic objectives of the exploitation distribution systems and systems use electrical energy.

The optimal solutions to these models, with applications on a OEL 20KV as an EDS subsystem, allow a fundamental planning of RCM, through: setting the optimal number of future actions for the preventive maintenance PM, on overhead electric line or its components; the optimal interval between actions; the optimum degree of safety in electricity supply; the optimal management of financial resources for RCM.

The results are summarized by an integrated software for the maintenance management, to manage the database regarding the history of events, as well as the RCM design and analysis. We consider the models presented can be developed in the following research directions: failure rate λ was considered constant throughout the PMA, although in reality it changes value after every action; the time between two successive renewals was considered constant, although it may be placed in the model, as a new variable to be optimized; in evaluation of costs did not take into account the influence of inflation, which could influence the results; last but not least, the lack of real databases, on technical and maintenance events, and their costs in relation to the components of the OEL.
