Research On Performance Evaluation And Fault Diagnosis Of Actuator

Equipment reliability management concept has been widely used in foreign equipmentmanagement, and has achieved significant economic benefits. Taking the nuclear power industry asan example, it is quite necessary to evaluate the reliability of nuclear power valve, the most widelyused equipment in nuclear power project, and it has been emphasized a lot in the third generationnuclear technology AP1000/CAP1400as the qualification evaluation and maintenance requirement.Therefore, this dissertation studies the performance evaluation and fault diagnosis used on theactuator. A set of control valve performance evaluation system has been designed and developed,and the results were analyzed through an actual case to do further research on the valve faultdiagnosis technology.First of all, the structure and its main accessories of actuators (also known as control valve) areintroduced by comparing the national standard of the main performance index of the valve. Then,the idea of the construction of a valve performance evaluation and fault diagnosis system ispresented. Through the design of the system framework, experiment platform construction, thedetermination of measuring parameters, device selection and system software development, acontrol valve performance evaluation system is designed.Secondly, literatures of control valve performance evaluation scheme from EPRI and ISA areanalyzed. Based on a test case of a control valve performance evaluation system, this paper furtheranalyzes the data curve and the singular point of a globe valve.Finally, based on the further research on the static friction force from the control performancetests, this paper sets the packing friction as an index to diagnose control valve fault. Bycomparatively analyzing the relevant parameters of the static friction force in a valve stem damagetest, this paper proves that in the valve actuator movement, the static friction force between thevalve stem and the sleeve can represent the performance state and fault condition of valve actuatorcomponents directly.The main innovation points in this dissertation are:(1)By comparing the national standard ofthe main performance index of the valve design standard, the idea of the construction of a valveperformance evaluation and fault diagnosis system is presented and a control valve performanceevaluation system is built.(2)The control valve performance evaluation is finished on a globe valve.The data and singular points are analyzed.(3)This dissertation sets the packing friction as an indexto diagnose control valve fault, and uses an experiment of diagnosing a stem damage valve to provethis conclusion. This dissertation is on the basis of a large number of papers, theoretical guidance, andespecially a large number of experimental results, which took almost1000hours in laboratory andenterprises. The research achievement has been successfully used in nuclear power valveproduction companies.