Thermal Power Unit Coordinated Control for Deep Peak Combustion Stability

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Solution Overview

Problem

Current coordinated control systems for thermal power units are inadequate for deep peak-regulating operations, leading to reduced boiler combustion stability, increased risk of boiler fire extinguishing, and instability due to fluctuations in fuel quantity, which are not effectively managed under conventional load conditions.

Innovation Solution

A flexible coordinated control method is introduced, incorporating a reverse compensation channel from fuel quantity instructions to power generation load instructions, using a main steam flow quantity signal to adjust the gain of this channel, and implementing modules for change rate limiting, amplitude limiting, and flexible factor compensation to prioritize combustion stability during deep peak-regulating conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the power generation load is reduced to enable deep peak-regulating operation, then the flexibility of thermal power unit is improved, but the boiler combustion stability deteriorates

Engineering Contradiction:

Improveflexibility of thermal power unitVSAvoidboiler combustion stability

Core Design Contradiction:

Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The patent implements a reverse compensation channel that forms a closed-loop feedback system. The fuel quantity instruction signal is fed back to adjust the power generation load instruction signal, creating a negative feedback mechanism that automatically corrects load fluctuations to maintain stable combustion during peak-regulating operations

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent applies change rate limiting and amplitude limiting to the power generation load instruction signal before it reaches the boiler control system. This preliminary action prevents excessive load changes that would cause combustion instability, ensuring the fuel quantity remains within stable combustion boundaries

Inventive Principle:

Principle #10Preliminary action

2Adaptability or versatility

If the fuel quantity is reduced to meet peak-regulating requirements, then the power generation load flexibility is improved, but the risk of boiler fire extinguishing increases

Engineering Contradiction:

Improvepower generation load flexibilityVSAvoidboiler fire extinguishing risk

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies amplitude limiting to the fuel quantity instruction signal to prevent it from falling below the minimum stable combustion threshold. This preliminary anti-action counteracts the tendency of fuel quantity to drop too low during peak-regulating operations, thereby preventing boiler fire extinguishing before it can occur

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The reverse compensation channel provides a cushioning effect by adjusting the power generation load instruction signal in advance based on fuel quantity conditions. This creates a safety buffer that prevents the system from reaching critical states where fire extinguishing would occur

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Manufacturing precision

If the conventional coordinated control system is used, then the control quality of power generation load is maintained, but the combustion stability under deep peak-regulating conditions deteriorates

Engineering Contradiction:

Improvecontrol quality of power generation loadVSAvoidcombustion stability

Core Design Contradiction:

Manufacturing precisionVSStability of the object's composition

Solution Approach 1:

The patent introduces dynamic adjustment mechanisms including change rate limiting and amplitude limiting that adapt the control system's response based on operating conditions. These dynamic elements modify the control characteristics to prioritize combustion stability during deep peak-regulating operations while maintaining control quality under conventional conditions

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent inverts the traditional control approach by creating a reverse compensation channel where fuel quantity instruction adjusts power generation load instruction, rather than the conventional forward control where load instruction determines fuel quantity. This inversion allows the system to prioritize combustion stability while maintaining load control quality

Inventive Principle:

Principle #13The other way round (Inversion)

Data Source

PatentUS11333045B1Flexible coordinated control method adapted to thermal power unit in deep peak-regulating operation

Publication Date: 2022.05.17 STATE GRID LIAONING ELECTRIC POWER CO LTD

AI summary

A flexible coordinated control method adapted to a thermal power unit in a deep peak-regulating operation includes: adding a reverse compensation channel from a fuel quantity instruction to a power generation load instruction on a basis of a traditional coordinated control system of a boiler-following mode; meanwhile, constructing a flexible factor by using a main steam flow quantity signal, and correcting a gain of the reverse compensation channel by the flexible factor in a product mode to obtain a reverse power generation load instruction bias value; and correcting the power generation load instruction of the unit by using the reverse power generation load instruction bias value, so as to give priority to guaranteeing the control quality of a power generation load and a throttle pressure before a steam turbine under conventional load conditions and give priority to guaranteeing the combustion stability under deep peak-regulating conditions.