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1、Introduction to E&I Safety Instrumented Systems (SIS) 电仪电仪 安全仪仪表系统统(SIS) 介绍绍2004-04-28 Ulrich Schuenemann BYC Nanjing BYC 南京 尤瑞奇 舒曼CTA Department E&I maintenance EOEG 电仪维电仪维 修EOEG CTA部2004-04-28 U.Schuenemann1Commissioning test of E&I SISlControl loops 控制回路DCSlMonitoring functions 检测功能 DCSlInterlock
2、s needed for smooth operation DCS, (ESD) 顺利运行所需的连锁lInterlocks related to plant Safety ESD 与装置安全有关的连锁There are different E&I functions 电仪电仪 功能各不相同2004-04-28 U.Schuenemann2Commissioning test of E&I SISWhat are E&I S.I.S. 什么是电仪电仪 S.I.S?E&I Safety Instrumented Systems (S.I.S.): 电仪安全仪表系统lS.I.S. prevent 安
3、全仪表系统用于防止 ：personnel injury 人身伤害或 environmental damage 环境破坏caused by a not tolerable fault state of the plant 由装置的不可接受的故障所造成 lS.I.S. are defined in the Safety Review Step 2.安全仪表系统是在安全风险评估的第二步中 定义的2004-04-28 U.Schuenemann3Commissioning test of E&I SISClassification of E&I functions 电电 仪仪功能的分类类2004-04
4、-28 U.Schuenemann4Commissioning test of E&I SISDefinition of SIS: Safety Review step 2 SIS的定义义: 安全审查审查 步骤骤2SEVERITY 严重性 S1 Potential for one or more fatalities S2 Potential for one or more serious injuries (irreversible) S3 Potential for one or more lost time injuries S4 Potential for minor injuries
5、, or irritationE&I SIS can be used for “risk class B and C”. 电仪SIS可用于 “B级和C级风险”Severity Probability 严严重性概率S1S2S3S4P0 (=1/y)ABDE P1 (1/10y)A/BBEE P2 (1/100y)BCEF P3 (1/1.000y)CDFFP4 (1/10.000y )EFFF2004-04-28 U.Schuenemann5Commissioning test of E&I SISExample: E&I Safety Review 2 Checklist 实实例: 电仪电仪
6、安全审查审查 2检查检查 清单单2004-04-28 U.Schuenemann6Commissioning test of E&I SISFailures of a S.I.S. S.I.S的故障lActive errortriggers off the safety function for no reason plant is switched back to safe operation reduction of production availability 有源故障 -无缘缘无故触发发安全功能 -装置切回到安全运行 -生产产运行可用率降低lPassive error 无源故障inh
7、ibits the required safety function plant continues operation although it should be switched off impacting the process safetyadversely affecting the safety function 对安全功能产生不利影响no adverse effect on the safety function 对安全功能无不利影响Failure 故障Time-averaged probability for a passive fault : PFD “Probability
8、 of Failure on Demand” 无源故障的时间平均可能性:PFD”指令故障的可能性“2004-04-28 U.Schuenemann7Commissioning test of E&I SISComponents of a SIS SIS的组组分Shut-Down System停车系统 Logic in Failsafe PLC or Hardwired system 在故障安全型可编程 控制器或硬接线系统 中的逻辑Redundant sensors 冗余的传感器Valve 阀门 Solenoid valve 电磁阀Instrument air supply仪表气源Rack Ro
9、om 机柜间Field 现场2004-04-28 U.Schuenemann8Commissioning test of E&I SISPassive Faults of sensors and actuators 传感器和致动器的无源故障mass flow meter after pressure pulse 压力脉冲下游的 质量流量计lost control valve plugcontrol valve plug, damaged by cavitationrestriction orifice, deformed by flow限流孔板限流孔限流孔板, 流量造成的变形调节阀阀塞,空穴造
10、成的损坏2004-04-28 U.Schuenemann9Commissioning test of E&I SISSome mathematics 一些算法TITest Interval between functional tests of SIS, time needed to discover dangerous faultsSIS功能测试之间的时间间隔, 发现危险故 障需要的时间 MTBFMean Time Between Failure of an equipment设备故障之间的平均时间 l = 1/ MTBFfailure rate 故障率Pf (t)Probability o
11、f failure (to function). For constant failure rates l :Pf (t) = (1 e-l t ) 故障概率(对功能而言).恒定故障率 l : Pf (t) = (1 e-l t ) PFDProbability of Failure on Demand = Pf (t) , time averaged over test interval TI指令故障概率= Pf (t) , 时间间隔TI的平均 时间PFD = 1/TI 0TI Pf (t) dt2004-04-28 U.Schuenemann10Commissioning test of
12、E&I SISPFD Probability of Failure on Demand PFD指令故障概率Probability Pf(t) for finding equipment in dangerous fault state after time t has passed since last functional test 自上次功能试验试验 以 来经过时间经过时间 t 后 ,发现设备处发现设备处 在危险险故障状态态 的概率.Pf (t) = (1 e-l t ) time average 时间平均值PFD Probability of Failure on demandPFDPF
13、D指令故障概率指令故障概率PFD depends on failure rate of equipment AND test interval. PFD取决于设备AND试验间隔的故障率2004-04-28 U.Schuenemann11Commissioning test of E&I SISCalculation of PFD PFD的计计算lPFD calculation of an individual equipment easy, if you havetest interval failure rate (given by supplier)如有试验间试验间 隔和故障率(供货货方提
14、供), 则则某个设备设备 的PFD计计算就不难难lPFD-calculation for more complex configurations (2oo3 etc. ) can be done using simple statistical models: Good for comparing different configurations. 用简单简单 的统计统计 模型可进进行较较复杂杂的配置(2003等)的PFD计计算lFor SIS: PFD of field domain and control domain must be added.对对于SIS: 必须须加上磁场场域和控制域
15、的PFDPFDSIS = PFDsensor + PFDPLC + PFDactuator 2004-04-28 U.Schuenemann12Commissioning test of E&I SISCalculation of PFD the problems PFD的计计算问题问题 lPFD data for field instruments usually not very reliable (not experimentally verified for chemical environment).用于现场仪现场仪 表的PFD数据通常不是很可靠(对对于化学 环环境未经试验验证经试验验证 ).lContribution to Failure Probability (PFD):对对故障概率 的影响因素lcalculated values for PFD: often not very accurate. lPFD计计算值值: 经经常不太准Field Instruments 85 % 现场仪表Logic Solver (failsafe PLC) 15 % 逻辑解答器 (故障保护PLC)
