Life cycle cost analysis of online dissolved gas analysis monitors

Abstract

A simple life cycle cost model for online dissolved gas analysers (DGA) has been developed. The model has been applied to two commercially available DGA instruments based on different operating principles; these consequently have different capital costs, consumable costs, maintenance requirements and reliability statistics. Reliability data has been derived from the in-service performance of the two different analysers. Using the model a number of sensitivity analyses have been performed to explore the results, as well as, consider the impact of operational realities such as the travel time to site to undertake repairs.The work shows that on-going operation and maintenance costs have a significant impact on the total cost of ownership; in particular, the number of call outs required to facilitate repairs. As such, the higher cost instrument which requires periodic consumables, has the lower total cost of ownership compared to the cheaper analyser which is consumables free, due to having a far higher reliability.