Optimize Decision-making Of Distribution Transformer Capacity Based On Full Life Cycle Cost Theory

Because of the huge number, distribution transformers owned a considerable proportionas the terminal of power distribution in power grid investment.Therefore, it is important valueto select the resonable capacity of distribution transformers, and save the cost of thedistribution transformer investment. At present, Chinese power enterprises tend to only focuson the initial construction investment of distribution transformers, and overlook the input ofthe late. This paper first combined the characteristics of various stage costs of distributiontransformers, then presented a general method which can be used in the whole process ofdistribution transformers, planning, design, procurement, construction, operation,maintenance, technical innovation, end of life, etc, and achieve a rational allocation ofresources. The paper has:Established distribution transformer life cycle cost model. In the model, transformercapacity is considered as a continuous variable, and distribution transformer’s powerinterruption loss model is established, which is a continuous function of the transformercapacity. It’s different from the other models which use average costs of power and averagefault repair costs. It can more precisely calculate the costs of power interruption loss. Inaddition, taking into account the planning capacity investment cost of higher power grid andthe time value of money, the thesis used aged value method to correct the model.This paper fitted the scatter of the relationship between operating loss and distributiontransformer capacity, then arrived the mathematical relationship of each parameter andcapacity to facilitate the solution of the model. With full life cycle cost model to optimize thecapacity of distribution transformer. Then all kinds of investment costs ofenergy-saving model, both energy and economic model are respectively calculated andcompared. We verified the excellent beneficial nature of the full life cycle cost model.Because of the risks of capacity selection caused by load average annual growth rate,This thesis adopted risk decision to assess the decision-making. Firstly, it depended ondifferent annual average growth rate of the load, chose several distribution transformercapacity plans preliminarily. Secondly, it used decision tree method to analyze the investmentrisks of the different programs. Finally determined the most appropriate program ofdistribution transformer capacity.Based on the heuristic enumeration method to select the initial distribution transformersin parallel operation combination. The paper calculated and compared the annual economiccosts of all kinds of combinations to determine each combination transformer put into operation in time oder. Finally, through the full life cycle cost model to calculate the cyclecost of all the programs, and select the most appropriate multiple transformers to run.