5. Conclusion
In this paper, we presented a synthesis of the various MV/ LV substation transformer, we have explained below the various documents constituting technical study, a detailed study of the public distribution substations (line diagram, the plan equipment, the choice of MV cells and MV / LV transformer, choosing the LV circuit breaker, the cables and the necessary safety equipment). Operating a distribution network requires switching points in addition to the MV/LV substations, in order to limit the effect of a fault on the network. To build a MV/LV substation transformer, it is necessary to size a number of parameters to achieve the appropriate wiring diagram. The development of these components must meet certain conditions dictated by the dual concern for the safety of operation and lower operating costs. These construction conditions can be classified into conditions related to tension, conditions relating to the thermal effects of the current, and conditions relating to the safety of operating personnel.