Gas Turbine Output Correction Using Multi-Period Degradation Coefficients
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Solution Overview
Problem
Existing gas turbine control methods fail to accurately reflect the degree of performance degradation after maintenance, leading to control failures when the turbine is restarted and performance is improved.
Innovation Solution
An output correction method for gas turbines that calculates a correction coefficient using multiple coefficient elements representing degradation over different time periods, allowing for accurate control output adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single correction coefficient based on the rate of decrease of output is used, then the control target can be appropriately controlled during continuous operation, but the correction coefficient does not appropriately reflect the degree of degradation after maintenance and repair
Solution Approach 1:
The patent divides the correction coefficient into multiple coefficient elements (first coefficient element based on reference output, second coefficient element based on immediately preceding output) to separately capture degradation from different time periods. This segmentation allows the system to accurately reflect performance degradation both during continuous operation and after maintenance by combining these elements differently based on operational state.
Solution Approach 2:
The patent implements dynamic adjustment of the correction coefficient by switching between different calculation methods based on operational state. During continuous operation, the coefficient reflects cumulative degradation; after maintenance, it resets to reflect improved performance. This dynamic behavior ensures the control system adapts to changing turbine conditions.
2Measurement precision
If the control output is corrected using the rate of decrease of output, then degradation during continuous operation is accounted for, but control failures occur when the turbine is stopped and repaired to improve performance
Solution Approach 1:
The patent incorporates feedback mechanisms by comparing the calculated correction coefficient against operational state information. When maintenance is detected (through changes in operational patterns or explicit signals), the system adjusts the correction coefficient calculation to reflect the improved performance state, preventing control failures that would occur with outdated degradation-based coefficients.
Solution Approach 2:
The patent changes the parameters used in correction coefficient calculation based on operational state. During operation, it uses output degradation rates; after maintenance, it transitions to using reference output values that reflect the restored performance. This parameter switching ensures accurate control throughout the turbine's operational lifecycle.
Data Source
AI summary
An output corrector is provided with an adjustment coefficient creating unit which creates an adjustment coefficient, an output adjusting unit which adjusts a control output using the adjustment coefficient, and an output accepting unit which accepts an output from an output meter for detecting the output of a gas turbine. The adjustment coefficient creating unit includes a first coefficient element calculating unit which calculates a first coefficient element, a second coefficient element calculating unit which calculates a second coefficient element, and an adjustment coefficient calculating unit which calculates the adjustment coefficient using the first and second coefficient elements. The first coefficient element is the ratio of an immediately preceding output in an immediately preceding time period, to a reference output at a reference time point in the past. The second coefficient element is the ratio of the current output in the current time period, to the immediately preceding output.