State Simulation And Fault Diagnosis Of Steam Turbine Rotor's Temperature Field

Steam turbine has been developed in the direction of large generating sets;more and more steam turbines are used in peaking units running in order to meet the electricity demand of economic and livelihood.In this case,there have been many problems,such as thermal stress;heat distortion;rotor's life span becomes shorter; poor running economy.These problems put forward more demands.Rotor is said as the most important part of steam turbine;its operation is under the most complex conditions,so the life span of rotor can be considered on behalf of the entire life of steam turbine units.Because of the nature of turbine rotor's work,temperature lies in an important position of turbine's complex conditions;temperature's change will touch other parameters and cause many faults.The study of rotor's temperature will provide a basis to understand the operation of steam turbine better and find relations between temperature and faults;it will also give some suggestions about preventing faults and optimizing the operation of turbine.Steam turbine rotor's temperature field data in various conditions is gained by finite element method.Start process and stop process are dangerous to steam turbine, rotor's analysis should emphasize them.Steam turbine's model is drawn in three-dimensional software and its drawings are supplied by Wuhan Steam Turbine Factory.The turbine's model number is C50-8.83/0.98.Finite element model is considered having more precision and needing analysis demands after comparing one-dimensional mode,two-dimensional differential model and finite element model. Rotor's simulation and analysis are made up of setting parameters,dividing into grids carefully in those places where rotor's temperature and thermal stress are high and analyzing.Steam turbine's start and stop curves are formulated by run descriptions.It will get start process and stop process's temperature features by analyzing their temperature fields.Analyzing reasons of rotor's faults can find relations between temperature and faults.Actual cases give operators some suggestions to prevent faults.Rotor temperature monitoring system is programmed by virtual instrument software.The system's main functions are displaying parameters of steam turbine, analyzing temperature data,recording history data to analyze operation,printing important data,estimating the rotor losses and reminding operators to take appropriate actions.