New Developments in Optimal Asset Management

Author(s): D. Zyngier, F. Welt, A. Bridgeman
Hydrovision Brazil 2013. Presented September 24-26, 2013

Abstract

With increasingly tighter regulations in hydroelectric operations and maintenance (O&M) comes a greater need for more efficient decision-making. To achieve maximum efficiency in relation to expenditures on maintenance of power system components, the total cost of capital expenditures (CAPEX) and the outage should be minimized. It is of utmost importance to obtain a CAPEX plan which defines preventative maintenance timings that minimize the risk of unforeseen failures while still optimally managing capital costs over a horizon of several years.

HydroVantageTM is a well-established decision-support tool that calculates the optimal economic trade-off between the capital costs associated with the rehabilitation/ replacement of assets and the risk costs associated to equipment failure and outages. This methodology is further supported by failure probability curves obtained from an extensive set of historical industrial data for hydroelectric facility assets. Several successful industrial implementations of HydroVantageTM have shown that the adoption of such an optimal risk-based asset management strategy can reduce overall cost of maintenance and outage by approximately 10 to 35%.

This paper presents two new developments that have recently been incorporated into HydroVantageTM: concurrent failures and optimized cost levelizing.

In some facilities, the costs of concurrent failures may be several times higher than the sum of the costs of the same failures occurring in different years. This may happen, for instance, in situations where the costs due to lost production increase sharply with the number of outages in any given year. The costs of concurrent failures across components may increase the risk cost considerably on older equipment and can now be explicitly considered in the optimal intervention strategy provided by HydroVantageTM.

In addition to the trade-off between risk and capital costs, it may also be important to limit total yearly investment amounts and/or define temporal constraints for certain investments, which may or may not have been explicitly included in risk-based assessment. The new cost levelizing functionality uses state-of-the-art Mixed-Integer Linear Programming (MILP) optimization technology to enable optimal balancing of capital expenditures while considering single- or multi-year investment limits, intervention time windows, intervention concurrencies and/or precedence relationships.