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Hi to all
We"ve done an HGPI on a frame6 turbine with S.T mark5 control system. first stage nozzle and first stage buckets were replaced. After starting the unit we saw wheelspace thermocouples 2AO1,2 and 3FO1,2 are high. In 18MW and 45" centigrade ambient both are above alarm (alarm is 510" for 2AO1,2 and 493" for 3FO1,2). Other wheelspace thermocouples and condition is normal. By reviewing the before HGPI data we noticed that this thermocouples temperature had been high (in 25MW and 25" ambient above alarm).
Washing has been done two times but nothing has been changed. Mechanical department says cooling path of stage two nozzle is blocked and rotor must be removed.
Now my question is what are the other possible causes for this event and is there any danger for turbine if with this condition works?
We"ve done an HGPI on a frame6 turbine with S.T mark5 control system. first stage nozzle and first stage buckets were replaced. After starting the unit we saw wheelspace thermocouples 2AO1,2 and 3FO1,2 are high. In 18MW and 45" centigrade ambient both are above alarm (alarm is 510" for 2AO1,2 and 493" for 3FO1,2). Other wheelspace thermocouples and condition is normal. By reviewing the before HGPI data we noticed that this thermocouples temperature had been high (in 25MW and 25" ambient above alarm).
Washing has been done two times but nothing has been changed. Mechanical department says cooling path of stage two nozzle is blocked and rotor must be removed.
Now my question is what are the other possible causes for this event and is there any danger for turbine if with this condition works?