城镇燃气中低压管网及系统失效事件特征及原因分析

Failure event characteristics and cause analysis of urban gas medium and low pressure pipeline networks and systems

基于2015—2020年某市城镇燃气中低压管网及系统失效事件的统计数据,从压力等级、投用年限、易发生故障部件和故障点埋深等维度分别对户内事件和外线事件进行特征及原因分析。特征分析结果表明:户内事件的高发时间为每年的3月、8月和11月,2018年和2020年引发的人员伤亡情况较严重,易发生故障部件包括法兰、阀门和燃气具;在外线事件中,投用年限超过15 a的管网占比为62.2%,易发生故障部件为管网母材、凝水缸和调压箱,且故障点多出现在埋深为0~2 m的区域。原因统计分析发现:户内事件的主要后果为泄漏、停气和燃爆,引发原因主要为第三方破坏和设备故障;外线事件的主要后果为泄漏,其中由腐蚀引发的泄漏事件占比为70.35%。通过计算失效概率可知,引发事件的最主要原因是腐蚀、设备故障和第三方破坏,最后有针对性地提出了事故预防措施。

To explore the statistical patterns of failure events in urban gas medium and low pressure pipeline networks,this paper classifies failure events into two categories,namely indoor events and external events,according to the locations of failure.Based on the statistical data of failure events of urban gas medium and low pressure pipeline networks and systems in a city from 2015 to 2020,the characteristics and causes of indoor and external events are analyzed in terms of pressure level,years of service,failure-prone components and depth of burial of failure points,respectively.The results of the analysis show that the highest incidence of indoor incidents occurs in March,August,and November each year,with more serious casualties in 2018 and 2020.Failure-prone components include flanges,valves,and gas appliances.In external incidents,62.2%of the pipeline networks are in service for more than 15 years,and the failure-prone components are the pipe master,condensate cylinder,and pressure regulator.The failure points are mostly found in the area with a burial depth of O-2 m.Statistical analysis of the causes revealed that the main consequences of indoor incidents are leakage,gas outage,combustion,and explosion,triggered mainly by third-party damage and equipment failure.The main consequence of external incidents is leakage,of which 70.35%are caused by corrosion.The calculation of the failure probability shows that the most significant causes of accidents over the years are corrosion,equipment failure,and third-party damage.Taking into account the influence of network materials and diameters,the state of corrosion protection and cathodic protection,geological conditions,and operation on the corrosion of gas networks,measures are proposed for the design phase,operation phase,and maintenance phase,respectively.In addition,measures are proposed to reduce equipment failure and avoid damage by third parties following the"3E"principle.