Steam Governing Valve Control for Power Transient Stability
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Solution Overview
Problem
During transient events in power systems, the steam governing valve operates in the closing direction due to increased or vibrating turbine rotation speeds, leading to a sharp drop in steam pressure and challenges in maintaining active power output after the system's restoration.
Innovation Solution
A control system comprising a transient-event detector and an opening-degree correction unit that maintains the opening degree of the steam governing valve at the same level as at the time of the transient event, thereby adjusting the steam flow into the steam turbine and ensuring consistent power output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the steam governing valve is controlled to close in response to increased or vibrating turbine rotation speed during transient events, then the turbine speed can be regulated, but the steam pressure drops sharply and active power output cannot be maintained
Solution Approach 1:
The control device detects transient events beforehand and preemptively adjusts the steam governing valve opening degree to counteract the effects of turbine speed fluctuations. By detecting the transient event and calculating a corrected opening degree that prevents excessive valve closing, the system maintains steam flow and power output before the harmful effect fully manifests
Solution Approach 2:
The control device continuously monitors turbine rotation speed, steam pressure, and power output, then adjusts the steam governing valve opening degree based on feedback from these parameters. During transient events, the feedback mechanism calculates a corrected opening degree that compensates for speed fluctuations, ensuring stable power output while regulating turbine speed
2Speed
If the steam governing valve closes to regulate turbine speed during transient events, then speed control is achieved, but steam flow amount decreases and system stability deteriorates
Solution Approach 1:
The control device detects transient events beforehand and preemptively adjusts the steam governing valve opening degree to counteract the effects of turbine speed fluctuations. By detecting the transient event and calculating a corrected opening degree that prevents excessive valve closing, the system maintains steam flow and power output before the harmful effect fully manifests
Solution Approach 2:
The control device continuously monitors turbine rotation speed, steam pressure, and power output, then adjusts the steam governing valve opening degree based on feedback from these parameters. During transient events, the feedback mechanism calculates a corrected opening degree that compensates for speed fluctuations, ensuring stable power output while regulating turbine speed
Data Source
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Figure 3A~3J
AI summary
The objective of the present invention is to provide a technique for controlling a steam governing valve of a power generation plant capable of maintaining an active power output after recovery from a power system transient event. A control system (10) for a steam governing valve of a power generation plant is provided with a transient event detecting unit (48) which detects an occurrence of a power system transient event, and an opening degree correcting unit (110) which, during the occurrence of the power system transient event, maintains an opening degree of a steam governing valve (13) for adjusting an amount of steam flowing into a steam turbine (18) to be in the vicinity the opening degree when the power system transient event occurred.