Steam Turbine Coupling Angle Control for Vibration Reduction
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Solution Overview
Problem
Current methods for coupling steam turbines and gas turbines in combined power plants often result in a random coupling angle, leading to increased vibration loads, despite the ability to minimize these loads by selecting a specific angle, which is not commonly practiced.
Innovation Solution
A method that involves accelerating the steam turbine to match the speed of the gas turbine, then further accelerating it to exceed the gas turbine speed briefly, allowing for a controlled engagement with a desired target coupling angle by adjusting the acceleration value and output speed difference, while accounting for clutch torsion angles to optimize vibration reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the coupling angle is selected to minimize vibration load, then the vibration load is reduced, but the coupling process becomes more complex and time-consuming
Solution Approach 1:
The steam turbine is accelerated to a predetermined output speed that is below the gas turbine speed before coupling. This preliminary speed adjustment creates optimal conditions for engagement, allowing the coupling to occur at the desired target angle while minimizing vibration load. The acceleration phase is completed in advance, so that when coupling occurs, the speed difference is already optimized for minimal vibration.
Solution Approach 2:
The method changes the speed parameter dynamically during the coupling process. The steam turbine is accelerated to a specific output speed below the gas turbine speed, then further accelerated to exceed the gas turbine speed briefly during engagement. This parameter change approach allows precise control over the coupling angle and minimizes vibration load while maintaining a relatively simple coupling process.
2Ease of operation
If the steam turbine is accelerated to match the gas turbine speed exactly before coupling, then the coupling is simpler, but the coupling angle becomes random and vibration load increases
Solution Approach 1:
Instead of maintaining a constant speed match, the method dynamically changes the steam turbine speed parameter. The turbine is first accelerated to an output speed below the gas turbine speed, then further accelerated to exceed the gas turbine speed during the brief engagement period. This parameter change ensures that coupling occurs at the optimal target angle rather than a random angle, reducing vibration load while keeping the operation relatively simple.
3Manufacturing precision
If the steam turbine is accelerated briefly above the gas turbine speed during engagement, then the target coupling angle is achieved, but the speed control becomes more difficult
Solution Approach 1:
The steam turbine is first accelerated to a predetermined output speed that is below the gas turbine speed before the engagement phase. This preliminary acceleration establishes a known baseline condition. Then, during the brief engagement period, the turbine is further accelerated to exceed the gas turbine speed. This two-stage preliminary action approach makes the speed control more manageable while achieving the precise target coupling angle.
Data Source
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AI summary
The invention relates to a method for coupling a rotational device, particularly a steam turbine, and a shaft device, particularly a gas turbine, said method comprising the following steps: 1) accelerating the rotational device up to an output rotational speed that is below the rotational speed of the shaft device; 2) detecting a differential angle between the shaft device and the rotational device; and 3) accelerating the rotational device with an acceleration value that is derived from the target rotational speed difference, which is formed as a function of the detected differential angle, the acceleration and a desired target coupling angle. The invention also relates to an associated arrangement.