This dissertation proposes the performance assessment process for helping the electric utility to determine and prioritize the workloads for replacement planning. The major equipment in this analysis consist of high voltage circuit breakers, disconnecting switches, current transformers, voltage transformers, and surge arresters. At the beginning of the process, the lifetime survey shows the present status of electric utility’s asset so that the utility can estimate their workloads of renovation tasks. At the present, the survey results suggested that a large number of aged equipment’s lifetime over their expected average lifetime in transmission network in Thailand are significantly high. In addition, the number of aged equipment which have the age over the expected lifespan will gain at high rate in the next few years.
The procedure to evaluate the remaining performance of major equipment has been set up by considering the age, electrical stress, symptom, failed type, obsolescence as well as environmental and safety impacts. Subsequently, the setup procedure has been developed as web-based management software via organization intranet. The example 115 kV high voltage substation has been demonstrated that the effective of the performance evaluation method by weighted score method (WSM) cooperated with the multi-criteria decision analysis assigning the weight factors called analytical hierarchy process (AHP). Moreover, the zero profit method (ZOP) is used for estimating economical performance of major equipment in terms of the remaining asset value and useful lifetime to ascertain those equipment should properly be renovated or normally maintained. Finally, the risk treatment process is used for migration the risk on that high risk substation. Moreover, the renovation planning can be subsequently determined and scheduled to set the budgets in short-term and long-term planning.