Power Plant Control System for Flexible Capacity
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Solution Overview
Problem
Existing power plant operations in deregulated markets face inefficiencies due to manual or complex automated measures for increasing flexibility and efficiency, which require frequent corrections and additional controllers.
Innovation Solution
An automated method for a power plant that calculates a target pressure value based on the primary control element's status to optimize gas and steam turbine operations, using an auxiliary heat source only when necessary to maintain efficiency and control within defined ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If manual or complex automated measures are used to increase flexibility and capacity, then power plant flexibility and capacity are improved, but efficiency deteriorates and device complexity increases
Solution Approach 1:
The control system automatically adjusts the auxiliary heat source based on real-time steam pressure and gas turbine status, eliminating the need for manual intervention and complex thermal balance calculations. The system serves itself by autonomously optimizing the operation of auxiliary burners and heat stores to maintain efficiency while providing flexibility.
Solution Approach 2:
The invention dynamically changes operational parameters (burner capacity, heat store discharge) based on real-time steam pressure measurements and gas turbine status. By continuously adjusting these parameters rather than using fixed manual settings, the system maintains maximum efficiency while adapting to varying load requirements.
2Power
If auxiliary heat sources are frequently used to increase capacity, then power plant capacity is improved, but efficiency deteriorates
Solution Approach 1:
The control system continuously monitors steam pressure upstream of the steam turbine and uses this feedback to determine when and how much to operate the auxiliary heat source. This closed-loop feedback ensures auxiliary heat sources are only activated when actually needed to maintain target capacity, avoiding unnecessary efficiency losses.
Solution Approach 2:
Instead of continuously operating auxiliary heat sources, the system applies partial action by activating them only to the degree actually required to maintain target capacity. The control system calculates the precise additional capacity needed and activates auxiliary heat sources only for that amount, minimizing efficiency deterioration.
3Measurement precision
If complex thermal balance calculations are used for pre-control, then control accuracy is improved, but device complexity and operational complexity increase
Solution Approach 1:
The invention extracts and eliminates the complex thermal balance calculation step from the control process. Instead of performing comprehensive thermal balance calculations, the system directly uses simple measurements of steam pressure and gas turbine status to determine auxiliary heat source operation, significantly reducing computational complexity while maintaining control accuracy.
Solution Approach 2:
The control system acts as an intermediary that simplifies the relationship between gas turbine operation and auxiliary heat source control. Rather than requiring complex thermal balance calculations to bridge these elements, the control system uses straightforward measurements and calculations to coordinate their operation, reducing overall system complexity.
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 method ensures maximum power plant efficiency by automatically adjusting capacity-increasing measures, reducing complexity and enabling precise start-ups without the need for thermal balancing or additional controllers, while maintaining stability and error tolerance.
Implementation Method 1
an auxiliary burner arranged in the heat recovery steam generator
Implementation Method 2
a heat store is employed as an auxiliary heat source. If required, heat is released from this store, and the steam pressure is thus further increased upstream of the steam turbine
Implementation Method 3
the steam output, and thus the electric power output of the steam turbine, can be reliably improved
Data Source
AI summary
A method for operating a power plant having a gas turbine, a heat recovery steam generator, a steam turbine, an auxiliary heat source, and a control system, wherein the method includes controlling the power plant such that the heat recovery steam generator receives an input of heat from the gas turbine; determining the gas turbine is operating at its maximum capacity or at an upper end of its control range and the power plant is operating at less than a target value for a power plant capacity; determining a target pressure value immediately upstream of the steam turbine, wherein the target pressure value is derived from a primary pressure for the steam turbine and a steam turbine capacity for the steam turbine; based upon the target pressure value, controlling the heat store to release heat into the heat recovery steam generator to achieve the predefined power plant capacity.