Novel performance diagnostic logic for industrial gas turbines in consideration of over-firing

초록

The performance of gas turbine degrades as the operating hours accumulate, and compressor fouling is the dominant factor. Compressor fouling can increase the turbine inlet temperature (i.e., over-firing). The diagnosis of over-firing is important because it affects the performance and lifetime of the turbine. This paper proposes new performance diagnosis logic for gas turbines that considers over-firing. The aim is to eliminate the effects of over-firing due to the compressor fouling. The key feature is analyzing the performance degradation based on modification in the turbine inlet temperature. An in-house code was developed to realize the logic. First, the code was verified through a comparison with a commercial software package, GateCycle 6.1.2, using real operating data of an industrial gas turbine during almost two years. Then, virtual operation data under compressor fouling were generated and used for the validation of the logic. The conventional diagnostic logic could predict the degradation in usual operation but could not evaluate the actual performance degradation correctly in a power control operation where power generation should comply with the power demand. However, the new logic evaluated the exact performance degradation for the entire period analyzed. The results confirm the importance of considering over-firing for exact performance diagnosis.

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