Study On Fault Reason Diagnosis For Steam Turbine Based On Fault Tree Analysis

Fault reason diagnosis takes an important position in fault diagnosis for Steam Turbine.The fault reason diagnosis should be an integral part of the fault diagnosis and provide the technical support for fault diagnosis.How to apply the fault reason analysis to the process of fault diagnosis so that the fault diagnosis can provides more valuable information for fault maintenance,How to apply the intelligent fault diagnosis for Steam Turbine method to the fault reason diagnosis to improve the accuracy and reliability of the fault reason diagnosis,Those questions need the further study.Fault tree analysis technique is a very effective diagnostic one in the fault reason diagnosis.Starting from the fault state,this method studies the relationship between the fault reason and the fault modes and plays a crucial role in the fault reason diagnosis system.Through the in-depth analysis of the fault tree and the integration with the project,this paper proposes a qualitative fault tree analysis technique based on component connection methods which resolves the issue of calculating combination explosion in the complex qualitative analysis of the fault tree and realizes the programmability of the qualitative fault tree analysis by converting the fault tree to the BDD means.The paper puts forwards the quantitative method of regarding the minimal cut sets as a whole and applies this method to the diagnosis optimization of the fault tree analysis.The expert system is the most active technical branch in the field of the intelligent fault diagnosis.This paper applies the expert system to the fault reason diagnosis technology and makes the preliminary diagnosis and reasoning on the fault reason with the expert system as a subsystem of the fault reason diagnosis system.By integrating this part with the subsystem of the fault mode diagnosis in the fault diagnosis system closely,it constructs the fault reason knowledge base with the expert knowledge in this field and makes the diagnosis and reasoning with the appropriate reasoning strategies and conflict resolution strategies.Through the in-depth analysis of the expert subsystem of fault reason and the fault tree analysis technique and the integration with their advantages respectively, this paper presents a method of the opumized sorting of the fault reason diagnosis which not only take into account two important factors of the minimal cut sets and the importance of components,but also determines the diagnosis order according to the results of the diagnosis causes symptoms and conditions by the expert subsystem and makes the comprehensive diagnosis based on several criteria for the fault diagnosis,thus greatly improving the accuracy of the fault reason diagnosis and helping troubleshooting and system maintenance.