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In our frame-5 dual fuel gas turbine we have got a high spread temp. and one TC is showing higher about 71C from the lower. There is no high temp. Spread protection configured in the Mark-V logic (which is very strange for me), the machine is old one from 1980s. we made CCI and found in one combustor direct below the nozzle is a burn in the body of the combustor and complete black part with expansion of this part like some explosion happened to it.
Specialist informed us to check exhaust thermocouples and we found some cables insulation between the thermocouples junction box and Mark-v in the J.Box it self ,this insulation has gone in some parts due to sun exposure and also high temperature then we checked the liquid purge valve PL20 and found its coil cut and it was not working.
The specialist told us that the problem of this purge valve caused this damage and burn of the combustion chamber due to oil nozzle was partially blocked and when we run on oil some of this oil was accumulated in this burned C.C. part and when we changed over to Gas this oil accumulation exploded causing the damage of the C.C.
My questions:
1- Can the failure and malfunctioning of the liquid fuel purge valve, PL-20 cause this damage to the C.C.?
2- How operator can know while turbine is running that this purge valve PL-20 has problem??
3- Is this logic not to have protection trip on high spread??
Specialist informed us to check exhaust thermocouples and we found some cables insulation between the thermocouples junction box and Mark-v in the J.Box it self ,this insulation has gone in some parts due to sun exposure and also high temperature then we checked the liquid purge valve PL20 and found its coil cut and it was not working.
The specialist told us that the problem of this purge valve caused this damage and burn of the combustion chamber due to oil nozzle was partially blocked and when we run on oil some of this oil was accumulated in this burned C.C. part and when we changed over to Gas this oil accumulation exploded causing the damage of the C.C.
My questions:
1- Can the failure and malfunctioning of the liquid fuel purge valve, PL-20 cause this damage to the C.C.?
2- How operator can know while turbine is running that this purge valve PL-20 has problem??
3- Is this logic not to have protection trip on high spread??