Marginal Effect Analysis Of Reliability Of Heating Network

With the rapid development of central heating,the scale and complexity of the pipe network are also increasing very fast.However,while the large-scale heating pipe network system brings people comfort and convenience,the accidents of the pipe network can not be ignored.The current research on the reliability of the heating network mainly focuses on the reliability evaluation,the influencing factors of the reliability and the frequency of the failure of pipes and pipe fittings,but neglects the analysis of the economic loss caused by the accidents of the heating network,?As a result,the reliability theory can not be well applied in practice without support of the economic theory.Therefore,the economic analysis of the reliability of heating network becomes an urgent problem.Based on the theory of safety economics and the reliability of heating network,this paper classifies the safety cost and accident loss of heating network clearly and gives the calculation method.We establish marginal benefit model of heating network,which combines the safety cost with accident loss by the failure rate of reliability theory.In the economic analysis,the pipe network model,which simplifies the complex design progress of heating pipe network,is established in order to control the factors affecting the reliability of the pipe network more convenient.Finally,we introduce the marginal analysis method to calculate marginal cost(MC),marginal loss(ML)and marginal effect(ME)of the reserve length,limited heating coefficient and accident rate parameters.In addition,make decision on the safety investment of heating pipe network through comparative analysis of data.The research shows that the safety degree of heating network is at a high level,the accident rate is low,and the MC of improving the safety degree is high.With the increase of the pipe diameter,the safety cost and accident loss of the heating pipeline increase synchronously,while the length of the pipeline will change,which has a greater impact on the safety cost than the accident loss,and the safety cost increases faster with the length of the pipeline.Different safety factors contribution to safety degree is different,and their ML and MC are different.For the branch network,the backup measures for the pipelines with large load can greatly enhance the safety degree of the high-level network,while the pipelines with small load have a large proportion of length,but have a small contribution to the safety degree.Therefore,to improve the safety degree of the branch network,priority given the backup measures for the larger diameter pipe.When the ML is greater than the MC,it is an effective and economic way to increases safety degree.In the ring network,because of its structural characteristics,the ring network system can maintain part of the heating capacity in case of accident.The increase of the limited heating coefficient is not obvious for the improvement of the safety degree of the ring network,and the ML is very low,so the economic value of increasing the limited heating coefficient is small.In the analysis of the network cost model,the ML brought by the reduction of the fault flow parameters is very high,and the ML of the branch network is higher than that of the ring network under the same load.Through the analysis of a specific network,we can calculate the specific ML.If the MC is lower than this value,reducing the fault flow parameters is the best way to obtain the safety income.