On the basis of analysing common failures occurred on the linear variable differential transducers(LVDT) of steam turbines

some retrofit measures

i.e.adding rotation-preventing device in the valve stem region of the govenor valve

adding universal coupling facility

adjusting the concentricity of LVDT

adding alarm logic for large deviation of govenor valve's stroke

etc.

have been put forward

and the LVDT of govenor valve for steam turbine of subcritical 600 MW unit in Guohua Jinjie Power Plant being retrofitted according to the said measures.After retrofitting

the phenomena occurred on the govenor valve

such as friction between feedback stem of LVDT and the sleeve

deformation of feedback stem in LVDT etc.

have never occurred again in trial operation of one year.All parts of LVDT are stressed uniformly

the feedback of valve position being accurately measured

the setting precision of govenor valve's feedback and the reliability in continous operation have been remarkabally enhanced.