Monte-carlo-based modeling of asset management of electric power apparatuses for assessing influence of wide variety of degradation extent and failure probability

This study proposes a numerical model to assess the usability of asset management of electric power apparatuses. A Monte-Carlo technique is employed, so that the various factors, i.e. the wide variety of degradation extent and failure probability among the electric power apparatuses, and the various replacement policy and constraints, etc, can be taken into account. As an example of electric power apparatuses, the model is applied for the asset management of 6.6 kV XLPE cables, where the maximum water-tree length is used as the degradation index. The replacement of cables by three situations is taken into account, i.e. failure, expiration of pre-determined service life, and detection of degradation index exceeding replacement criteria. The LCC of each cable is calculated based on the calculated numbers of failure, replacement and diagnosis. The mean value and variation of LCC of a set of cables is evaluated by summarizing the various values of LCC of each cable. The optimum asset management is evaluated as the situation with the minimum LCC, which is derived by adjusting replacement criteria and diagnosis interval. The proposed model is applied to discuss the influence of upper limit of annual replaceable cables on the optimum management as an example of replacement constraints.