Combined-Cycle Plant Startup Sequencing for Target Load Balance
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Solution Overview
Problem
In multi-shaft combined-cycle power plants, it is challenging to balance the output of gas turbine generators and the steam turbine generator to achieve a target load, as the sequence of activating or shutting down gas turbines affects the steam turbine's vapor content and output, making it difficult to perform these operations efficiently.
Innovation Solution
A plant operation apparatus with an interactive processing unit and sequence processing unit that displays and generates activation and shutdown sequences for gas turbines, allowing users to select and simplify the operation by displaying activation and shutdown setting screens, generating sequence information, and outputting operation commands based on the selected sequences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sequence of activating or shutting down gas turbines is considered to balance generator outputs, then the target load can be achieved, but the operation complexity increases and becomes difficult to perform
Solution Approach 1:
A sequence processing unit is introduced as an intermediary component that automatically determines and manages the activation/shutdown sequence of gas turbines. This mediator receives target load information, calculates the appropriate sequence considering steam turbine vapor content constraints, and outputs control signals to execute the sequence, thereby resolving the complexity burden from operators while ensuring reliable target load achievement
Solution Approach 2:
The system enables self-service operation by automatically determining the gas turbine activation/shutdown sequence based on pre-stored operational data and target load requirements. The sequence processing unit autonomously performs calculations and generates control sequences without requiring operator intervention in complex sequence planning, making the system self-sufficient in managing operational complexity
2Ease of operation
If gas turbines are activated or shut down sequentially to balance outputs, then generator output balance can be achieved, but the steam turbine output changes largely due to vapor content changes
Solution Approach 1:
The system performs preliminary actions by pre-storing operational data including vapor content characteristics and output relationships of various gas turbine combinations. Before executing activation/shutdown operations, the sequence processing unit retrieves this pre-prepared data to determine sequences that maintain steam turbine vapor content within acceptable ranges, thereby preventing large output fluctuations in advance
Solution Approach 2:
The system implements feedback mechanisms by continuously monitoring the actual number of operating gas turbines and comparing it with the planned sequence. The sequence processing unit adjusts subsequent activation/shutdown decisions based on this feedback to maintain steam turbine vapor content within ranges that ensure stable output, creating a closed-loop control system that balances generator outputs while stabilizing steam turbine performance
Data Source
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AI summary
A plant operation apparatus according to an embodiment operates a multi-shaft combined-cycle power plant including at least a plurality of gas turbines as a plurality of devices to be operated. The plant operation apparatus includes an interactive processing unit and a display unit. The interactive processing unit can display on the display unit an activation setting screen on which activation sequence in an activation operation of the gas turbines and number of gas turbines to be in an operating state after the activation operation can be selected, or a shutdown setting screen on which shutdown sequence in a shutdown operation of the gas turbines and number of gas turbines to be in an operating state after the shutdown operation can be selected.