Gas turbine gas‐path fault diagnosis in power plant under transient operating condition with variable geometry compressor

Abstract To extend useful life, improve availability, and reduce gas turbine maintenance costs, scholars have proposed many gas‐path fault diagnostic approaches on the basis of steady‐state operating conditions. However, gas turbines increasingly have to operate more flexibly in grid‐supported modes. In transient operating mode, the service life of the gas turbine will be consumed faster compared with that in base‐load operating mode. In addition, the use of a variable geometry compressor has introduced new uncertainty in the actual diagnostic process, making the applicable boundaries of the original gas‐path diagnosis methods narrower and narrower. Regarding the issue above, a novel approach is proposed for fault diagnosis of gas turbine gas‐path components in power plants under a transient operating condition with the variable geometry compressor for the first time. First, the mathematical relationship of the influence of the compressor inlet guide vane position on the compressor flow and efficiency characteristics is deduced. And a high‐precision thermodynamic model for the purpose of performance analysis and gas‐path fault diagnosis is established, which comprehensively considers the above interference factors and includes health parameters of the main gas‐path components. Second, the thermodynamic model‐based diagnosis strategy under transient operating conditions with the variable geometry compressor is proposed and component health parameters can be quantitatively obtained. At last, the effectiveness and reliability of the method proposed are validated through both simulation test and actual operation test with good accuracy and real‐time performance to diagnose single and multiple component performance degradations, and component abrupt fault.