Converter-Controlled Wind Power Grid Support During Faults
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Solution Overview
Problem
Synchronous generators in electricity supply grids can experience oscillatory excitations and instability during grid faults, which can lead to frequency oscillations and potentially disrupt the grid, especially when decentralized generators like wind farms rapidly adjust their power input.
Innovation Solution
A method for exchanging electric power with the grid using a converter-controlled generation unit that switches between normal and support control functions based on grid state variables like voltage and frequency, with the support control function specifically designed to counteract oscillations and stabilize the grid during faults by adjusting active and reactive power inputs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If decentralized generators rapidly adjust power input to support the grid during faults, then grid support effectiveness is improved, but oscillatory excitation of synchronous generators increases
Solution Approach 1:
The patent implements dynamic control of power adjustment by decentralized generators during grid faults. The control system continuously monitors grid conditions and adapts the power injection rate in real-time, transitioning from static to dynamic operation. This allows the system to provide rapid grid support while avoiding excessive oscillatory excitation by adjusting the rate and magnitude of power changes based on actual grid response.
Solution Approach 2:
The patent employs feedback control mechanisms where the behavior of synchronous generators is monitored and used to adjust the power adjustment strategy of decentralized generators. The control system detects oscillatory tendencies and feeds this information back to modulate the power injection, creating a closed-loop control system that balances grid support effectiveness with stability maintenance.
2Speed
If converter-controlled generation units quickly respond to grid faults, then response speed is improved, but oscillation counteraction effectiveness may be reduced
Solution Approach 1:
The patent implements preliminary action by pre-configuring control strategies and power adjustment profiles that are activated immediately upon fault detection. The system prepares multiple pre-defined response scenarios and selects the appropriate one based on fault characteristics, enabling rapid response without the delay of real-time calculation and optimization during the critical fault period.
Solution Approach 2:
The patent transitions from static pre-programmed responses to dynamic adaptive control. The system continuously adjusts power injection based on real-time grid conditions, oscillation characteristics, and synchronous generator behavior. This dynamic approach allows the system to maintain fast response while adapting the control strategy to counteract specific oscillation patterns as they develop.
Data Source
AI summary
Provided is a method for exchanging electric power with an electricity supply grid that has a grid frequency using a converter-controlled generation unit that may be a wind power installation or a wind farm, at a grid connection point. The method includes exchanging electric power depending on a control function. The electric power includes active and reactive power and the control function controls the power depending on at least one state variable of the electricity supply grid. It is possible to switch between a normal control function and a support control function, different from the normal control function, as the control function. The normal control function is used when it has been recognized that the electricity supply grid is operating stably and the support control function is used when a grid fault or an end of the grid fault has been recognized.