Research On Performance Simulation And Fault Characteristics Of Dual Shaft Gas Turbine

As an excellent energy equipment,gas turbines have extremely wide applications in many fields,such as energy,power generation,military,ship and so on,because of its small size,large power and strong maneuverability.Therefore,it is very important and necessary to ensure the safe and reliable operation of gas turbine and to carry out condition monitoring and fault diagnosis.Generally,the causes of gas turbine faults can be divided into two categories:the first is mechanical causes,which can be detected by vibration analysis,oil analysis and other methods.The second reason is the performance reason.There is no direct indicator or parameter characterization for this kind of fault,but they will cause the change of measurement parameters or related parameters,such as pressure,temperature,fuel flow,etc.Therefore,it is necessary to establish the corresponding performance simulation model to associate the directly measured parameters with the performance parameters that can not be directly obtained,so as to assist the on-site condition monitoring system to monitor the gas path status of gas turbine.In view of the above problems,this paper studies the performance simulation and fault characteristics of the double shaft gas turbine.Based on the high-precision real-time performance simulation model,the gas path state early warning method is proposed.Based on the gas path fault model,the typical gas path fault identification method is proposed.First of all,in view of the low simulation accuracy and low simulation efficiency of the general performance model in the actual application process,this paper proposed a real-time high-precision performance simulation method.Based on the measured data,the simulation initial point of the simulation model was adapted to make the simulation model closer to the actual gas turbine performance,thereby improving the simulation accuracy of the model.At the same time,an error module was introduced to control the relative accuracy of the parameters to avoid over-simulation or non-convergence in the process of the model’s pursuit of high precision,which improves the real-time performance of the simulation model.Finally,a high-precision real-time performance model of a dual-shaft gas turbine was constructed.The accuracy and real-time performance of the established model were verified.The results show that the accuracy and real-time performance of the model meet the actual engineering requirements.Afterwards,for how to apply the performance simulation model to the gas path state early warning,this paper proposed a performance simulation based gas path state early warning method.First,based on the performance simulation model,an early warning feature was constructed,that is,the deviation of the gas path parameters.This feature considers the influence of the ambient parameters on the fluctuation of the gas path parameters of the gas turbine and the characteristics of the gas turbine under variable operating conditions.Subsequently,the threshold of this feature was studied,and a method of generating an alarm threshold based on kernel density estimation was proposed.In the end,a warning method for the gas path was formed by combining this warning feature and its threshold generation method.After the verification of the measured data,the early warning method proposed in this paper can effectively judge the gas turbine gas path status compared with the traditional threshold alarm method.Finally,in view of the problem of how to identify faults after early warning,this paper constructed a gas path fault model and integrated typical gas path fault criteria to propose a gas turbine typical gas path fault identification method.First,the small deviation equation of each component was established according to the small deviation linearization method,and the fault components in the performance parameters were separated at the same time,thereby establishing a gas path failure model.After introducing the performance criterion of typical gas circuit faults into the fault model,the fault characteristics under typical gas circuit faults were obtained.Finally,based on the typical fault characteristics,a gas path fault recognition method based on pattern similarity was proposed.After verification by the measured data,the method proposed in this paper was effective and feasible.