Research On Related Alarm Analysis And Suppression Strategy Of Petrochemical Process Industrial

Alarm system is an essential automation security system of modern petrochemical process industry,which including software and hardware,monitoring the operating state of alarm variables or devices,and informing the operator when normal operation limits are exceeded.It easy to set an alarm,but too many alarm systems configurations end up as miserable failures.In many cases,the causes can be traced back to the unreasonable alarm configuration and unreasonable alarm response,which are interactional in the alarm management life circle.The most common problem of alarm system is providing more extraneous information,for example nuisance alarm,chatting alarm,related alarm and alarm flood.As a result,operators are faced with a challenging environment,having more alarms than they can effectively handle.So alarm system without timely response becomes a bad system and a harmful tool.Alarm rationalization,in fact,seeks to identify unnecessary alarms with wrong setting values in order to improve the current procedures for dealing with alarms.As efficient alarm management is important for petrochemical process industry operating safety,it is significance to research on related alarms and suppression strategy.The related alarms and suppression strategy presented in this paper includes priority quantizing determination,alarm grouping and suppression,alarm tree model.Priority quantizing determination is based on available response time and the severity of consequence.Human factor is taken into account by Human Cognizance Reliability(HCR)model to predict the response behavior.The available response time is quantified through Mean Time to Response(MTTR)factor,and severity through evaluation of six categories of consequence.An equation is proposed to work out an accurate priority score,and then alarm priority is determined.If alarms are related to one another,those alarms should be grouped and presented as one alarm problem.A strategy that alarm grouped based on cluster analysis of alarm data and alarm suppression according to the priority in group is presented in this paper.The aim of this strategy is to reduce the number of alarms presented to the operator and help operator to recognize the correlation among alarms.Based on alarm nodes and fault propagation path,a tree diagram describing the logical relationship of alarms is developed to help the operator be able to fulfill his required tasks to keep the plant within safe operation limits and to find the root cause of the disturbance in alarm flood.It is helpful for improving response efficiency and alarm system performance.The combination of these three method yields an effective related alarm and suppression strategy that can help plant owners and operators to comply with standards for alarm management such as ANSI/ISA 18.2(2009)and EEMUA 191(2007)which set Key Performance Indicators of alarm system.The effectiveness of the approach is illustrated in TE process where a significant reduction of alarms has been achieved and the root alarm has been diagnosed.