A maintenance decision optimization method based on life cycle cost of converter transformer

Converter transformer is one of the most important equipment in ultra-high voltage direct current transmission system, periodic preventive maintenance strategy is widely in its maintenance. Excessive maintenance often arises in the attempt to always ensure the reliable operation of converter transformers. To solve this problem, this study proposes a maintenance decision optimization method for converter transformers that is based on life-cycle cost(LCC). This approach introduces the concepts of LCC and discount rate, obtains an LCC model of the converter transformer and presents the value conversion method; by improving the maintenance equipment failure rate and the calculation method of economic losses, this method improves the accuracy of failure loss cost in the LCC model; by comparing the different maintenance modes of the converter transformer LCC, the reasonable maintenance strategy is optimized, thereby achieving the objectives of reliability and economy. A decision-making example using a ±800kV converter transformer shows that the proposed method can calculate the LCC of converter transformers, yield the optimized maintenance strategy and provide technical support for condition-based maintenance of the converter transformers.