This paper presents a methodology for optimal long-term maintenance schedule of distribution networks. The methodology is based on risk management approach and the new model of decoupled risk factors and state transition based on decision tree diagram. Risk approach provides more realistic modeling of component failure and estimation of expected consequences, while decoupled risk factors enable definition of selective plan for preventive actions. The proposed methodology is tested on a real overhead distribution network, but it can be used for other parts of distribution system as well. Obtained results have shown that the expected costs of distribution network maintenance can be reduced and the risk of emerging of significant operation costs minimized, by detailed and realistic modeling of risk factors
