The energy consumption increases year by year due to the growth of the population and theeconomic conditions. In this context, the Cambodian government promotes and encourages thedevelopment of the electrification through several policies; all the villages must be electrified by2020 and at least 70 % of the households will be connected to the network by 2030. Besides, lotsof non-electrified homes are equipped with solar panels so as to have access to the electricity. Then,the objective of this thesis is to develop planning tools of the low voltage distribution network tocontribute to the electrification of the country. The first part of this thesis focusses on thedevelopment of architecture’s optimization methods to minimize the capital expenditure (CAPEX)and operational expenditure (OPEX) while respecting both topological and electrical constraints(current and voltage) and integrating the uncertainties on the future development of the low voltagecustomers. The second part of the thesis proposes a new planning solution so as to integrate thecurrent and future solar productions on the low voltage network. This solution consists in addingcentralized storage (in urban and rural areas) and decentralized storage (in rural areas). The mainadvantages would be first to reduce the consumption peak of the medium voltage /low voltagetransformer and consequently to reduce the medium voltage investments but also to size low voltage"microgrids" which can be autonomous a big part of the year. A technical and economic comparisonwith the classic solution of reinforcement allows estimating the interest of this new solution.