Research On Reliability Predication And Life Cycle Cost Assessment Of Low-voltage Switchgear

Aiming at discussing the reliability growth prediction method,improving the reliability prediction accuracy,extending the data,and searching the optimum service life of low-voltage switchgear,the reliability prediction method and life cycle cost(LCC)assessment method,are explained in details in this paper.The emphasis and achievement of the paper mainly manifest in the following aspects:Firstly,the reliability growth prediction methods of low-voltage switchgear were researched.The two methods,the generalized gamma distribution prediction theory of low-voltage switchgear and the conditional distribution reliability growth prediction of low-voltage switchgear,were proposed.The future failure time and the mean time between failures(MTBF)were predicted.And the prediction accuracy and the applicability of the proposed methods were dicussed.To reduce the influence of prediction step,the improved AMSAA model reliability growth prediction method was proposed.The predictor of future failure time was taken as a simulation data and combined with actual data to predicate the MTBF and the next future failure time,which can reduce the influence of long prediction step on research results.Secondly,the availability prediction method of low-voltage switchgear was proposed based on a hierarchical Markov model.The low-voltage switchgear was divided into modules and the modules were divided into other layers.The reliability calculation method of parallel unit based on state transition was proposed to calculate parameter of every layer.By analysis of the first layer and the second layer,the availability of low-voltage switchgear can be obtained and the key module can be identified.By analysis the others layers,the key component can be identified,which provides a new method to obtain the availability of low-voltage switchgear and other repairable complex systems.Then the LCC of low-voltage switchgear was evaluated.The LCC estimate model of low-voltage switchgear costs was established.The improved GM(1,1)model was proposed to extend the failure data of low-voltage switchgear.According to the grey maximum relational principle,the optimum distribution type of instantaneous operating maintenance cost in the LCC estimate model was determined by the extended data.And the optimum service life and minimum cost in the life cycle of low-voltage switchgear were obtained from LCC estimate model simulation.Finally,the reliability prediction soft system of low-voltage switchgear was designed.The system contains data management subsystem and data analysis subsystem.The former can realize data storage and modification.The latter can realize the reliability assessment and reliability prediction.