A Techno-Economic Framework for Replacing Aged XLPE Cables in the Distribution Network

In this paper, a stochastic framework is proposed for optimizing replacement strategies of aged XLPE cables in the electric power distribution network. The proposed framework facilitates realizing an economic value for the risk of unplanned outages, thereby shifting the paradigm of replacing aged XLPE cable from a technical decision that is solely based on diagnostic measurements to a techno-economic strategy. The proposed framework constitutes of three main phases: (1) obtaining a distribution for the aging process of XLPE cable due to water-trees, (2) modeling the replacement of the aged XLPE cable as a Markov decision process, and (3) applying a linear programming algorithm in order to solve for the optimal replacement policy. Based on the proposed framework, a critical health index is defined for optimum replacement, depending on the installation costs of a new cable and the unplanned outage cost.