Gas Turbine Risk
Gas turbines feature high combustion temperatures, highly stressed compressor and turbine blades, and complex control and fuel systems, so foreign object damage, flashback or blade failure can cause total losses with long outage times.
Failure mechanisms
Gas turbines compress intake air, mix it with fuel and expand the hot combustion gases across several turbine stages; blades reach temperatures close to the material limit in the process. Ingested foreign objects such as dust, ice or bird strike damage compressor blades, while flashback, combustor instabilities or a malfunction of the fuel control system can cause overheating or blade burn-through. Creep and thermomechanical fatigue of the hot-section components additionally limit their usable life.
Protection concept
The protection concept includes effective air filtration and anti-icing at the compressor inlet, redundant fuel and flame monitoring, and continuous vibration and exhaust temperature monitoring for early detection of blade or bearing damage. Borescope inspections of the combustor and first turbine stages during planned outages complement the online monitoring.
Insurance relevance
Because of their high replacement value and long lead times for rotors and nozzle guide vanes, gas turbines are among the most critical single units in power plants and industrial facilities. For machinery and business interruption insurance, operating hours history, inspection intervals and the availability of replacement components are key factors in risk classification.
Standards and codes
- ISO 20816-2:2017 – Mechanical Vibration, Measurement and Evaluation of Machine Vibration, Part 2: Land-Based Gas Turbines, Steam Turbines and Generators in Excess of 40 MW