Steam Turbine Start Control Unit Thermal Elongation Management
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing methods for starting a steam turbine plant quickly to stabilize power generation require complex calculations to manage thermal elongation differences between the rotor and casing, which can lead to reduced reliability and performance due to potential contact between the rotating and stationary parts.
Innovation Solution
A start control unit that adjusts steam flow rates based on measured and estimated temperatures of the steam, rotor, and casing, increasing the steam flow rate when the temperature differences between these components are within specific regulated values, thereby reducing thermal elongation differences without complex calculations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the steam turbine is started quickly (high-speed start), then the productivity and responsiveness of the power generation plant is improved, but the thermal elongation difference between the rotor and casing increases, which may cause contact between rotating and stationary parts, reducing reliability
Solution Approach 1:
The control unit dynamically adjusts steam flow rate parameters based on real-time temperature measurements. When the temperature difference between rotor and casing exceeds the regulated value, the steam flow rate is increased to accelerate casing heating and reduce the temperature difference, thereby preventing thermal elongation contact while enabling high-speed start
Solution Approach 2:
The system implements closed-loop feedback control by continuously monitoring the temperature difference between rotor and casing through temperature sensors, comparing it against the regulated value, and automatically adjusting the steam flow rate accordingly. This feedback mechanism ensures the thermal elongation difference is suppressed to the regulated value or smaller throughout the start-up process
2Reliability
If the thermal elongation difference is suppressed by controlling steam flow rate using conventional methods, then the reliability is improved, but the control system requires complicated calculations and thermal elongation difference estimation, increasing device complexity
Solution Approach 1:
The invention extracts and directly controls the key parameter (temperature difference between rotor and casing) that determines thermal elongation difference, rather than calculating and controlling the thermal elongation difference itself. This simplifies the control logic by eliminating complex thermal elongation estimation calculations while maintaining effective suppression of thermal elongation differences
Solution Approach 2:
The control unit monitors the actual temperature difference parameter between rotor and casing in real-time and adjusts steam flow rate based on this direct measurement, replacing complex thermal elongation calculations with simple temperature differential control. This parameter substitution significantly reduces computational complexity while improving control accuracy
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively suppresses thermal elongation differences, quickens the start of the steam turbine, and enhances the reliability and performance of the plant by promoting heat transfer and reducing the thermal elongation difference between the rotor and casing.
Implementation Method 1
high-temperature steam is fed, the casing and rotor are heated by the heat of the high-temperature steam, and elongation is generated in both the casing and the rotor due to the thermal expansion
Implementation Method 2
the casing and rotor are heated by the heat of the high-temperature steam
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A start control unit for a steam turbine plant, characterized by inputting a measured value of a steam temperature fed to a steam turbine 3, a measured value or an estimated value of a rotor temperature of the steam turbine 3, and a measured value of a casing temperature of the steam turbine 3, and controlling a steam flow rate so as to increase the steam flow rate fed to the steam turbine 3 when a difference between the steam temperature and the rotor temperature is smaller than a first regulated value and a difference between the rotor temperature and the casing temperature is a second regulated value or larger.