Asset Simulation and Life Cycle Assessment for Gas Insulated Substation

An important task of the asset management process is the evaluation of the long-range investment and resource planning of the assets of the complete power system and the life cycle cost assessment of different type of substations. The calculation of the long-range investment and resource planning can be performed by using dynamic asset simulation tools, which represent the statistical behavior of the complete asset group over a time range of 40 to 60 years. The final result is the evaluation of the total investment and operational expenditures as well as the comparison of different investment and maintenance strategies. The replacement rate of the different types of asset can be described by statistical data, e.g. Gaussian density functions, which can be gained from experience of the asset manager or from published reports. Depending on the age distribution of the installed assets, the number of the components to be replaced over the simulated time range can be evaluated. Under consideration of the yearly outage and maintenance costs the total costs of ownership can be calculated each year depending on the different group of costs. With consideration of the different expenditures and the knowledge how many components per year have to be maintained and replaced and on the basis of the failure rates (“major” and "minor" failures), in principle it is possible to evaluate the total expenditures for a group of equipment and in consequence for the entire system during the complete simulation period (e. g. 50 years). The life cycle cost (LCC) assessment consists of three main cost elements, the cost of acquisition, the cost of ownership and the renewal cost. These three cost elements are evaluated based on experience and on statistical data. According to the present value method all payments in the future, i. e. cost of ownership (costs for scheduled and unplanned maintenance) and renewal costs, have to be represented as present values related to the year 0, at which an interest rate of 10% and an inflation rate of 2.15% per year is taken into account. Finally, for evaluation of the total life cycle costs the different cost shares are accumulated, at which a period of consideration of 40 years and 50 years respectively is regarded.