Wind Converter Control for Weak Grid Stability
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Solution Overview
Problem
Wind farms connected to remote electrical grids face instability due to low short circuit ratios (SCR), leading to insufficient power delivery and potential shutdowns, as the long transmission lines increase impedance and decrease SCR, making it challenging to provide stable power to the grid.
Innovation Solution
A system and method for controlling wind converters that include multiple control loops to calculate and regulate power transfer based on electrical grid parameters and wind converter characteristics, converting voltage references into current references associated with angle information, and using a phase lock loop to stabilize power transfer, even in weak grid conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If wind farms are located at remote locations far away from major electrical grids, then the wind farm can access suitable locations for wind energy generation, but the long transmission lines increase impedance and decrease the short circuit ratio (SCR), resulting in unstable power delivery
Solution Approach 1:
The patent changes the control parameters of the wind converter by implementing a multi-loop control system that dynamically adjusts voltage and current references based on grid conditions. The control system modifies operating parameters including voltage magnitude, frequency, and phase angle to maintain stable power delivery despite varying transmission line impedance and low SCR conditions
Solution Approach 2:
The patent implements feedback control mechanisms where the control system continuously monitors grid parameters and wind converter characteristics, then adjusts the voltage and current references accordingly. This closed-loop feedback ensures the wind farm adapts to changing grid conditions and maintains reliable power delivery to the electrical grid
2Productivity
If the short circuit ratio (SCR) falls below 4, then the wind farm operates in weak grid conditions, but the wind farm cannot deliver sufficient power to the grid and experiences shutdowns
Solution Approach 1:
The patent implements dynamic control that adapts to varying grid conditions in real-time. The control system continuously adjusts voltage and current references based on current grid parameters and wind converter characteristics, allowing the wind farm to maintain optimal performance across different SCR conditions including weak grid scenarios where SCR falls below 4
Solution Approach 2:
The control system performs preliminary calculations to determine appropriate voltage and current references before power delivery adjustments are needed. By pre-computing control parameters based on current grid conditions and converter characteristics, the system prepares optimal settings that prevent shutdowns and maintain continuous operation
Data Source
AI summary
This disclosure relates to systems and methods for controlling a wind converter for a weak electrical grid. In one embodiment of the disclosure, a system for controlling the wind converter includes a wind converter connected to an electrical grid at a point of connection (POC) and operable to transfer a power to the electrical grid. The system includes a first control loop operable to calculate, based on electrical grid parameters and wind converter characteristics, a voltage reference to be generated by the wind converter. The system includes a second control loop to convert, based on the electrical grid parameters, the voltage reference into a current reference. The second loop converts the angle information of the voltage reference into a voltage at the POC. The system includes a third control to regulate, based at least on the current reference, the power transferred by the wind converter to the electrical grid.