I
Hello everyone
I hope you are in good health.
We are facing problem with the HP differential of our Steam turbine. Recently our turbine has been on partial load for quite some time due to the demand of national grid, we have been changing over the turbine from full load to partial load continuously from last month.
After the continuous operation on partial load, values of differential has increased to â 1.8 mm at full load i-e 105 MW (inlet temperature of main steam being 535 C) which used to be less than -1 mm in past.
Currently, the Alarm setting of HP differential is at -2.5 mm and trip has been set at -2.8 mm. From the OEM provided quality hold points documents we found that the recommended clearance between stationary diaphragm and rotor (for HP) is around 7 mm (min).
All other operational and mechanical parameters are running in normal condition.
I need to know the following:
1) What are the basis of setting alarm value at -2.5 mm if the clearance is higher which is around 7 mm (min)?
2) What are the recommended checks which should be carried out to analyze the increased HP differential expansion issue?
3) What precautions should be taken to avoid this issue in the future?
Will appreciate any response from anyone.
Thank you.
I hope you are in good health.
We are facing problem with the HP differential of our Steam turbine. Recently our turbine has been on partial load for quite some time due to the demand of national grid, we have been changing over the turbine from full load to partial load continuously from last month.
After the continuous operation on partial load, values of differential has increased to â 1.8 mm at full load i-e 105 MW (inlet temperature of main steam being 535 C) which used to be less than -1 mm in past.
Currently, the Alarm setting of HP differential is at -2.5 mm and trip has been set at -2.8 mm. From the OEM provided quality hold points documents we found that the recommended clearance between stationary diaphragm and rotor (for HP) is around 7 mm (min).
All other operational and mechanical parameters are running in normal condition.
I need to know the following:
1) What are the basis of setting alarm value at -2.5 mm if the clearance is higher which is around 7 mm (min)?
2) What are the recommended checks which should be carried out to analyze the increased HP differential expansion issue?
3) What precautions should be taken to avoid this issue in the future?
Will appreciate any response from anyone.
Thank you.