Exergy Storage Correction for Coal-Fired Unit Frequency Regulation
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Solution Overview
Problem
Thermodynamic system regulation schemes of coal-fired units during transient processes are unable to accurately and automatically participate in primary frequency regulation, leading to insufficient regulation ability and operational inflexibility.
Innovation Solution
An optimized control method based on exergy storage correction, which determines the optimal primary frequency regulation control scheme by calculating real-time exergy storage amounts and exergy storage variation for each thermodynamic device, selecting the most suitable regulation scheme, and integrating it into the primary frequency regulation control logic using pressure and temperature sensors, and PID controllers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional regulation schemes are selected based on steady-state regulation ability, then the regulation scheme selection is simple, but the regulation ability becomes insufficient during transient processes
Solution Approach 1:
The patent applies dynamics by transitioning from static steady-state regulation ability assessment to dynamic transient process analysis. It calculates exergy storage variation rates in real-time during transient processes to determine regulation schemes, making the selection adaptive to changing system states rather than relying on fixed steady-state characteristics
Solution Approach 2:
The patent changes the assessment parameter from steady-state regulation ability to exergy storage variation rate during transient processes. By using exergy storage variation rate as the new parameter, the system can accurately evaluate and select regulation schemes based on actual transient process conditions, resolving the contradiction between selection simplicity and regulation effectiveness
2Reliability
If thermodynamic system regulation schemes are used during transient processes, then the regulation ability improves, but the control complexity increases
Solution Approach 1:
The patent implements feedback by continuously monitoring exergy storage variation rates and using this information to automatically adjust regulation scheme selection. The system establishes a closed-loop control where transient process parameters are measured, evaluated, and used to determine optimal regulation actions, improving reliability while managing complexity through systematic feedback mechanisms
Solution Approach 2:
The patent applies self-service by enabling the thermodynamic system to automatically evaluate its own transient state through exergy storage calculations and self-select appropriate regulation schemes without external intervention. This self-evaluation and self-regulation capability improves control effectiveness while reducing the need for complex external control systems
3Adaptability or versatility
If exergy storage correction method is implemented, then the predictive accuracy and operational flexibility improve, but the calculation complexity and data requirements increase
Solution Approach 1:
The patent applies preliminary action by pre-establishing the exergy storage calculation framework and data collection systems before transient processes occur. It prepares the computational structure and sensor networks in advance, so that during transient processes, the system can quickly calculate exergy storage variation rates without dealing with the full complexity of real-time system setup, thereby improving operational flexibility while managing calculation complexity
Data Source
AI summary
An optimized control method for a primary frequency regulation based on art exergy storage correction of a thermodynamic system of a coal-fired unit is provided. Through measuring and recording temperatures and pressures of working fluids and metal heating surfaces of the coal-fired unit thermodynamic system in real-time, an exergy storage amount of the thermodynamic system is obtained. During a transient process, according to an exergy storage variation before and after acting of each regulation scheme, a maximum power output of each scheme is obtained. Thereafter, through comparing the maximum power output with a power regulation quantity required by a power grid, an optimal primary frequency regulation control scheme is selected, so as to maintain a fast and stable grid frequency. The present invention reduces a selection blindness of the primary frequency regulation schemes, so that an operation flexibility of the coal-fired power unit during the transient processes is greatly improved.