Life Cycle Costs Evaluation And Life Prediction Of Low-voltage Switchear

Low-voltage switchgear is an electrical equipment with the circuit breakers,fuses and many other low-voltage electrical apparatus assembled together in a structural unit.It is responsible for the control,protection,measurement,transformation and distribution of electrical energy in power system.Therefore,low-voltage switchgear is a key equipment to ensure the normal operation of low-voltage power grid.At present,low-voltage switchgear costs evaluation method is not perfect.Usually only the purchase cost of low-voltage switchgear is concerned,while other costs are ignored.In this way,the costs of expenditure are not fully considered,so that the utilization rate of funds is lower.Low-voltage switchgear mainly adopts preventive planned maintenance mode,which lacks of theoretical support and does not take the operation of the equipment into account.So it would lead to excess maintenance of equipment and insufficient maintenance of equipment,and then reduce the cost of economy of equipment maintenance.In view of the above two problems,the costs evaluation and life prediction were carried out for low-voltage switchgear in this paper.The life cycle costs management theory was introduced into the costs evaluation of low voltage switchgear.And the life cycle costs of low-voltage switchgear was decomposed into the one-time investment cost and the maintenance cost.Considering the uncertainty of the maintenance cost,the GM(1,1)model was used to fit the distribution types of the maintenance cost.Then,the life cycle costs evaluation model of low-voltage switchgear based on grey system theory was established.Finally,the optimal service life and the minimum life cycle costs of low-voltage switchgear were obtained by simulation and calculation of the model.The three-parameter Weibull distribution model was introduced into the life prediction of low-voltage switchgear,and then combined with the conditional probability theory in statistics,the residual life prediction model of low-voltage switchgear based on Weibull distribution was proposed.By simulation and calculation of the model,the residual life of low-voltage switchgear was calculated.So the task for predicting the residual life of low-voltage switchgear was realized.The results of life prediction were analyzed and found to be consistent with the actual situation,which proved the accuracy of the life prediction model.