Wind Farm Voltage Control Using Equivalent Grid Estimation
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Solution Overview
Problem
Existing voltage control methods for wind farms struggle with stability due to reliance on local voltage measurements, leading to fluctuations in reactive power and delayed responses, especially in weak grids, which are not adequately addressed by current control strategies that require sophisticated communication systems or result in additional voltage fluctuations.
Innovation Solution
A voltage control method that estimates the equivalent grid voltage based on measurements at the connection point, using an equivalent grid model to generate a stable reactive power command, thereby minimizing delays and fluctuations, and dynamically adjusts control parameters in response to changes in grid impedance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If voltage control is based on local voltage measurements at the connection point, then the control response is rapid and no additional control equipment is needed, but the voltage control stability deteriorates and additional voltage fluctuations occur
Solution Approach 1:
The patent introduces an equivalent grid voltage as an intermediary parameter that mediates between local measurements and global grid conditions. By using this intermediary representation, the system achieves both rapid local response and stable global control, resolving the contradiction between fast response and stability.
Solution Approach 2:
The patent implements feedback control by continuously monitoring local voltage measurements and adjusting the reactive power command based on the equivalent grid voltage model. This feedback mechanism ensures stability while maintaining rapid response capability.
2Speed
If sophisticated communication systems are used to connect wind farm controller to wind turbines, then rapid response can be obtained, but device complexity and cost increase
Solution Approach 1:
The patent extracts the essential control function from complex communication systems by using only local measurements at the connection point. By taking out the unnecessary communication infrastructure and focusing on critical local data, the system achieves rapid control without sophisticated communication networks.
Solution Approach 2:
The wind farm controller serves itself by using local measurements and an equivalent grid model to generate control commands, eliminating the need for external communication systems to coordinate with individual wind turbines. The system is self-sufficient with local information.
3Ease of manufacture
If digital delays and communication delays are present in the control system, then the system is easier to implement, but voltage fluctuations and reactive power fluctuations increase
Solution Approach 1:
The patent performs preliminary action by calculating the equivalent grid voltage model in advance based on local measurements. This pre-computed model compensates for digital and communication delays, allowing the system to maintain stability despite implementation simplicity.
Data Source
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AI summary
The invention relates to a voltage control method for a power generation plant, which generates reactive power according to the evolution of voltage, in such a way that it contributes to stabilise the grid voltage, the voltage control system that comprises the abovementioned voltage control method and the wind farm comprising said control system. In accordance with this method the equivalent grid voltage is estimated (VGrid) based on the electric magnitudes measured at the connection point of the power generation plant (VSub, Pglobal, Qglobal, Iglobal, cos fi), and an equivalent model of the power grid to which the power generation plant is connected; and on the basis of said calculated equivalent voltage (VGrid) a command is generated (Qref) indicative of the reactive power to be produced by the power generation plant.