Risk Assessment And Warning Decision Methods For The Gas Pipelines Operation

As a kind of high efficient,clean and new energy,gas is conducive to solve air pollution problems,promote urban development and improve people's life quality.Gas pipeline called the lifeline of urban operation undertake the function of gas transmission and distribution,which is related to the normal operation of gas companies and people's daily life.Natural gas,artificial gas and liquefied petroleum gas transported and stored by gas pipeline system is flammable and explosive,so they are major hazard sources in the operation of city,whose operational safety issues are strongly linked to urban development.From the perspective of ensuring the safe operation of gas pipeline,this paper makes assessments to the possibility of gas pipeline operation risk and the consequence seriousness,based on the identification of the various risk factors in the process of the gas pipeline operation.Furthermore,the time dimension is added to the risk assessment model of the gas pipeline and the dynamic risk assessment of the gas pipeline is carried out.Finally,the risk warning model of the gas pipeline is carried out based on the Pressure-State-Response model.The content is as follows:1.Risk identification of gas pipeline operation.As the risk information of gas pipeline is difficult to be completely perceived and quantified,we analyze the risk factors of gas pipeline operation,then we improve the close degree of grey incidence in gray relational analysis.Based on the comprehensively close degree of grey incidence,the risk identification model of gas pipeline operation is developed to analyze the development trend of various risk factors that affect the operation of the gas pipeline system and could be perceived.By observing whether the development trend between the risk factors is the same,we find out the main influence factors.2.Possibility assessment of gas pipeline operation risk.Combining the characteristics of gas pipeline accident and the objective reality,we construct the risk index of gas pipeline operation from the angle of human,material,environment and management,and determine the weight of each index by AHP scale extension method.On this basis,a gray multi-level assessment model of the possibility of gas pipeline operation risk is established according to the gray characteristics of the gas pipeline operation process.Finally,we obtain the corresponding risk rank of the gas pipeline operation risk by the gray assessment value and give the special control advice of gas pipeline operation risk.3.Assessment of gas pipeline accident consequence.Based on possibility assessment of gas pipeline operation risk,we further make the consequences assessment of gas pipeline accident.Since the assessment indexes need to be given in the form of exact values,interval values and fuzzy language variables,grey linguistic 2-tuple is used to evaluate the consequences of gas pipeline accidents.The mixed index data composed by the exact values,interval values and fuzzy languages is transformed into grey linguistic 2-tuple.We obtain the assessment value by the gray mixed index data,and sort the assessment values.Then we give the rank of the accident consequences.4.Dynamic risk assessment of gas pipeline operation.As the risk situation of each gas pipe section changes with time,in order to reflect the dynamic nature of the gas pipeline operation risk,we add a time dimension on the basis of risk assessment,and make the dynamic risk assessment of gas pipeline in the multi-dimensional space of index and time.The matrix proximity grey relational analysis model of gas pipeline's dynamic risk assessment is established by using the ideal matrix method.The risk of each pipe section is sorted by the degree of grey incidence between weighted criteria evaluation matrix and ideal matrix.Then the risk rank is given.5.Risk warning decision of gas pipeline operation.Considering the relationship between the occurrence of the gas pipeline accident and the human factors and the environmental factors,we establish the risk warning index system of the gas pipeline operation by the Pressure-State-Response model and the threshold intervals are given.On this basis,the gray clustering evaluation model is optimized by the principle of maximizing the total deviation quadratic sum of the whitening weight of the clustering index,and a risk warning model of the gas pipeline operation is established based on gray clustering.The warning rank of each pipe section is confirmed.