Control Device for Autonomous Power System Recovery
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Solution Overview
Problem
Existing power system recovery methods, such as black start, face challenges in selecting an appropriate control scheme for power sources during frequency changes after a power outage, as they do not account for varying frequency characteristics post-outage.
Innovation Solution
A control device for AC power systems that includes a frequency control unit, power calculation unit, and selection unit to vary the frequency of the power source, calculate the frequency characteristics constant, and select an appropriate control scheme based on these calculations, enabling autonomous recovery without external power sources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the frequency characteristics constant is calculated by varying the output of the generator or load connected to the power system, then the frequency characteristics constant can be determined, but this method does not account for black start scenarios and fails to provide control scheme selection for power sources during autonomous recovery
Solution Approach 1:
The control device performs preliminary actions by calculating the frequency characteristics constant before the power source is fully connected to the power system. This preliminary calculation enables the system to determine the appropriate control scheme in advance, ensuring proper control during autonomous recovery operations without requiring external command information.
Solution Approach 2:
The control device enables the power source to serve itself by autonomously calculating the frequency characteristics constant and selecting the appropriate control scheme based on the calculated value. This self-service capability allows the power source to independently determine its control parameters during black start scenarios without external assistance.
2Productivity
If a predetermined control scheme is selected for the power source during black start, then the power system can be recovered autonomously, but the control scheme may not be optimal as frequency characteristics change when other power sources are connected
Solution Approach 1:
The control device implements dynamic control by continuously monitoring the frequency characteristics constant and adjusting the control scheme based on the calculated value. This dynamic approach allows the control parameters to adapt to changing frequency characteristics as other power sources are connected to the power system, optimizing performance throughout the recovery process.
Solution Approach 2:
The control device uses feedback by calculating the frequency characteristics constant based on the actual frequency and power output of the power source, then using this calculated information to select the appropriate control scheme. This feedback mechanism ensures that the control scheme remains optimal as the power system evolves during autonomous recovery.
3Measurement precision
If the frequency of the power source is varied to calculate the frequency characteristics constant, then the appropriate control scheme can be selected, but this requires additional control operations during the recovery process
Solution Approach 1:
The control device achieves multi-functionality by combining the frequency variation process with the control scheme selection process. The same frequency variation operations that are necessary for accurate measurement of the frequency characteristics constant also provide the data needed for control scheme selection, eliminating the need for separate control operations and reducing overall complexity.
Data Source
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AI summary
A control device (10) for controlling a power source (20) connected to an alternating-current (AC) power system includes: a frequency control unit (201) that controls a frequency of the power source operating in a constant-voltage constant-frequency control scheme; a power calculation unit (203) that calculates, when the frequency control unit varies a frequency of the power source, a variation of an effective power output from the power source; an arithmetic unit (205) that calculates a frequency characteristics constant of the AC power system, based on a variation of the frequency of the power source and the variation of the effective power output from the power source; and a selection unit (207) that selects a control scheme for the power source, based on the frequency characteristics constant of the AC power system.