Converter-Controlled Infeed Unit for Grid Stabilization
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Solution Overview
Problem
The integration of renewable energy sources, particularly wind power, into electricity supply grids faces challenges due to high converter penetration, leading to weakened voltage support and potential power fluctuations, which can cause mechanical stress on wind turbines and torque fluctuations.
Innovation Solution
A method involving a converter-controlled infeed unit that uses a delayed differential angle and grid impedance to predefine infeed power, allowing for current-injecting behavior that stabilizes the grid without exclusive voltage injection, thereby reducing the impact of voltage fluctuations and providing a damping effect.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If voltage-injecting converters are used to provide strong voltage support and damping properties, then grid stabilization is improved, but power fluctuations increase and mechanical stress on wind turbines worsens
Solution Approach 1:
The patent changes the control parameters by using delayed differential angle (a temporal parameter) and grid impedance (an electrical parameter) to modulate the infeed power, transitioning from direct voltage injection to a more nuanced current-injecting approach that achieves stabilization without excessive power fluctuations
Solution Approach 2:
The patent introduces dynamic adaptation by continuously adjusting the infeed power based on real-time grid conditions (voltage phase angle changes and impedance variations), allowing the system to respond dynamically to grid changes while maintaining stability without the rigid power fluctuations of voltage-injecting converters
2Adaptability or versatility
If current-injecting converters are used to quickly adapt to grid changes, then adaptability is improved, but voltage support capability worsens
Solution Approach 1:
The patent implements feedback control by continuously monitoring grid voltage phase angle and impedance, using this information to adjust the infeed power through the delayed differential angle mechanism, thereby maintaining both adaptability to grid changes and adequate voltage support capability
Solution Approach 2:
The patent introduces the delayed differential angle as an intermediary parameter that mediates between the current-injecting converter and the grid, allowing the converter to adapt quickly to grid changes while the intermediary mechanism ensures voltage support is maintained through controlled power modulation
3Speed
If voltage-injecting operation is used to achieve fast response to voltage changes, then response speed is improved, but power fluctuations increase beyond available reserves
Solution Approach 1:
The patent applies partial action by using only the necessary amount of power modulation required for grid stabilization, rather than the excessive power variations needed for direct voltage injection, achieving fast response through controlled current injection modulated by delayed differential angle and grid impedance
Data Source
AI summary
Provided is a method for feeding electric power into an electricity supply grid via a connection node by way of a converter-controlled infeed unit, in particular by way of a wind power installation or a wind farm. The grid has a grid voltage and a grid frequency and is characterized by a grid nominal voltage and a grid nominal frequency. The grid voltage of the grid is acquired, a delayed differential angle is ascertained on the basis of the acquired grid voltage. The delayed differential angle corresponds to a difference between an acquired phase signal that indicates a temporal profile of a phase angle of the grid voltage and a phase signal that is delayed with respect to the acquired phase signal. A grid impedance effective for the connection node is acquired, and an infeed power is predefined based on the delayed differential angle and based on the impedance.