I operate frame 6b gas turbine. The turbine was installed and commissioned in 2009, so it's quite new engine. And during commissioning, we performed overspeed test, both electrically and mechanically. The insurance guy asked me to perform overspeed test once in every single year, mechanically and electrically. He said it is the industrial best practice for gas turbine.

Is that right? Because I am afraid that the test is quite destructive for the gas turbine and only tested during commissioning. Am I wrong?

 

Our 9Es have to be tested once in every 3 years. Not sure if this makes any difference but our control system incorporates a SIL panel. The only stipulation we have is that the test must be done at the normal trip speed, which is 110 per cent. Reduced setpoint or offline simultation tests with a frequency generator will not be considered valid for insurances purposes. Our units do not have a mechanical overspeed bolt. We have redundant overspeed trips in both the SIL and BPCS panel but only required to demonstrate the SIL. There is also online and offline tests built into the SIL panel which we never use.

This is likely to vary from country to country but the insurance assessors will have the last say unless convinced otherwise.