Steam Turbine Coupling via Target Acceleration

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Solution Overview

Problem

Current methods for coupling steam and gas turbines in combined power plants lack an efficient and targeted approach to achieve a desired coupling angle, leading to suboptimal vibration load management and synchronization.

Innovation Solution

A method involving the detection of differential angles and speeds between the turbines, prediction of the coupling angle based on acceleration, and calculation of a target acceleration to match a desired clutch angle, allowing for controlled and synchronized coupling without requiring direct measurement of acceleration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the steam turbine is accelerated with a simple constant acceleration, then the control system is simple, but the coupling angle cannot be precisely controlled and vibration loads are not minimized

Engineering Contradiction:
Improvecoupling angle precisionVSAvoidcontrol system complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The system performs preliminary detection of the differential angle and differential speed between the two turbines before coupling. Based on these detected values, the control unit calculates and sets a target acceleration that will achieve the desired coupling angle. This preliminary action allows precise coupling angle control without requiring complex real-time adjustments during the acceleration process.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The control system detects the actual differential angle and differential speed, compares these values with the target values, and adjusts the acceleration accordingly. The control unit calculates a target acceleration based on the detected state and feeds this back to the steam turbine controller, ensuring the coupling angle is precisely achieved while maintaining relatively simple control hardware.

Inventive Principle:
Principle #23Feedback

2Object-affected harmful factors

If the coupling angle is randomly determined, then the control system is simple, but the vibration load is maximized and turbine imbalances add up

Engineering Contradiction:
Improvevibration loadVSAvoidcontrol system complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

Before coupling occurs, the system detects the differential angle and differential speed between the turbines. The control unit uses these detected values to calculate a target acceleration that will result in the desired coupling angle, thereby minimizing vibration loads. This preliminary calculation ensures that turbine imbalances are compensated rather than added up, reducing harmful vibrations without requiring complex additional hardware.

Inventive Principle:
Principle #10Preliminary action

3Manufacturing precision

If the steam turbine is accelerated to match gas turbine speed without targeted control, then the coupling process is simple, but the coupling angle cannot be optimized for vibration reduction

Engineering Contradiction:
Improvecoupling angle controlVSAvoidcoupling speed
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The system replaces complex mechanical coupling alignment mechanisms with a computational approach. The control unit detects the differential angle and differential speed, calculates the appropriate target acceleration, and controls the steam turbine acceleration accordingly. This substitution of mechanical alignment with computational control achieves precise coupling angle optimization while maintaining efficient coupling speed.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentEP3426897B1Method for coupling a steam turbine and a gas turbine with a desired difference angle using target acceleration
Publication Date: 2020.01.01 SIEMENS AG
  • EP3426897B1 patent drawingFigure 1~3
  • EP3426897B1 patent drawingFigure 4~5

AI summary

The invention relates to a method for coupling a rotating device, in particular a steam turbine (5), and a shaft device, in particular a gas turbine (2), having the following steps: – detecting a differential angle (7) between the shaft device (2) and the rotating device (5); – detecting a differential speed (8) between the shaft device (2) and the rotating device (5); – predicting a coupling angle at which the rotating device (5) and the shaft device (2) would be coupled if the rotating device (5) were accelerated with a known acceleration up to the start of the coupling-in; – comparing the predicted coupling angle (10) with a target coupling angle (11), and calculating therefrom a setpoint acceleration (9) such that the predicted coupling angle (10) matches the target coupling angle (11).