Improved Fault Rate Of The Cycle Cost Of Transformer Based On Mondified Failure Rate Model

As the core equipment in the electrical power system,transformer is a important research object by lots of engineers and science researcher in production and living field and scientific research field.In the actual research,it always from economic and scientific side to discuss the tansformer's effectiveness.The aim of transformer research is to make sure transformer itself is in low failure rate,low accident rate,safe operation to help decision maker to arrange maintenance reasonably,and meanwhile,to low down the inspection fees,save labor cost and maintenance cost to make it has a good economic efficiency.Firstly,this paper make a brief analysis of the life cycle cost of the transformer,it considers site selection and construction of substation from the perspective of electric power company,this paper divide the life cycle cost of the transformer into four parts including cost of investiment,cost of operation,cost of failure and cost of discard.And also considering the economic impact on the life cycle cost.Then,from the history data,taking the transformer's main structure fault as the main part bond with the tansfromer fault rock this paper build a fault tree of transformer and considering the concept of probability importance in safety engineering assign weights for the bottom event of the fault tree.Based on more than one transformer failure rate calculation,it can use Marquardt algorithm to match curve to obtain a function of transformer failure rate and time.The traditional transformer failure rate only simplely considering time factor without considering the transformer's status,so the failure rate estimates is only a rough estimation.In this paper,further improvement here,through the introduction of the notion of transformer health index it get the new function relate the failure rate with time and healthy index.This function can make a more accurate fault rate estimation.On the basis of above work,this paper caculate a real example of transformer.Firstly,it can calculate a single fixed recursion transformer failure rate through the fault tree,then calculate different recursion transformer failure rate repeatly and it can get the distribution curve of transformer failure rate.Secondly,it considers the healthy state caused by the maintenance of transformer to draw the corresponding transformer real failure rate curve so as to calculate the life cycle cost of transformer.The four part of this paper verifies the feasibility and availability of the method in the paper.It can help decision maker to make decision in selection of the transformer and transformer condition maintenance.