Research On The Procurement Of 220kV Power Transformer Based On Whole Life Cycle Cost Theory

With the development of power industry reform,transmission and distribution(T&D)companies are facing the new operation mode that transmission and distribution tariffs are regulated by the government.In the future,the costs of transmission and distribution services provided by the network company,and the income from transmission and distribution services will be regulated by the authorized entity,the regulator.The power grid surveillance is based on the value of transmission and distribution assets of the grid company.Therefore,the strategy of a grid company is changed from system operation to asset management.Transformer,which has relatively high value and long operation life-cycle,is one of the core components of transmission and distribution facilities.By introducing the concept of life cycle cost(LCC)in purchasing high quality and high reliability facilities with most economic ways,it is possible to solve the asset management issue as well as adapt to the future surveillance mode.Moreover,it can mitigate the difficulties caused by lack of maintenance staff.In this paper,we will first introduce the procedures of purchasing power transformers,and analyze the problems in existing purchase procedures.For example,the facilities could have high possibilities of fault events,which affect the power grid safety operation.To solve the issue,a set of purchase strategies base on LCC management for 220 kV power transformers are proposed.The strategies are designed and calculated according to the investment cost of each stage of the whole life cycle,operation cost,maintenance cost,fault cost,and retirement cost.Based on the proposed strategies,the mathematical model for LCC of 220 kV power transformer is obtained,and the solution algorithms are provided.Not all detailed costs are covered in the mathematical model for simplicity.Those extremely similar costs are ignored,especially for the LCC comparison of different transformers.The mathematical model has been tested and verified with practical procedures in real power grid applications.The test covers the whole life cycle of the 220 kV power transformers.It starts from the preparation stage,such as,determine technical parameters,prepare tendering document,and design tender forms satisfying the requirement of LCC calculation.Then the second stage to call for tender,evaluate the auctions,and follow-up suppliers and tender results.Till the last stage to analyze the results of the facility purchase with suggestions for improvement.The purchase strategies and the mathematical models proposed in the paper have explored practical applications of whole life-cycle theory to power grid operation.It provides valuable methods and verified experiences for purchasing of other higher value T&D facilities.