A new asset value estimation using zero profit method for renovation planning of high voltage equipment in power substation

摘要

This paper presents a new asset value estimation of high-voltage equipment for renovation planning in power substation. The high-voltage equipment includes power transformer, high-voltage circuit breaker, current transformer, voltage transformer, disconnecting switch, and surge arrester in 115 and 230 kV substations. The zero profit method is applied to estimate the asset value of equipment. To obtain the zero profit, the summation of maintenance cost and outage cost are annually compared with the remaining asset value. At the point of zero profit, the useful lifetime of equipment is given. From this point onwards, the utility obtains risk from further usage of equipment because the total maintenance and outage costs are greater than the remaining asset value. Additionally, the utility encounters the high risk to outage according to high probability of failure of the degraded equipment. The asset value and useful lifetime estimation of high-voltage equipment in two 115 kV power substations in Thailand transmission network are presented. The asset value of all equipment and bays in such power substations are evaluated in order to prioritize the maintenance tasks of equipment and bays. This zero profit method is a simple but powerful tool to determine the net asset value of existing equipment, which can significantly help the utility to allocate the tight budget, to plan the effective maintenance of equipment and to make a decision whether to repair or to replace of the aged equipment.