Assessment of different power line types´ life-time costs in distribution network from reliability point of view

The paper presents developed approach for assessment of middle voltage network life-time costs (from utility point of view) related with usage of different type power lines. Proposed approach takes into account construction, maintenance and fault elimination costs depending on each power line type (overhead line, isolated wire overhead line, high overhead line or underground cable line) features. Paper also includes description of developed approach for estimation of customer costs of reliability that takes into account time-variable loads and outage costs. The developed approaches were implemented in case studies using information about structure of real distribution network used in Latvia. Results obtained from the calculations give well-grounded base for distribution network exploiting engineers when trying to find network´s optimal reliability level by replacing overhead lines by other types of power lines as one of network reliability centered maintenance and reconstruction activities.