Wind Farm Feed-In Control for Subsynchronous Resonance Damping
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Solution Overview
Problem
Low-frequency oscillations in electrical supply grids, such as subsynchronous resonances, can cause damage to synchronous generators and lead to grid instability, especially with the increasing presence of decentralized wind power systems, which complicates damping due to changing network properties.
Innovation Solution
A method for controlling wind power systems to damp low-frequency oscillations using a closed-loop control system that adapts to the entire frequency range of low-frequency oscillations, incorporating a network oscillation model and wind system model to prevent weakly damped modes, with a robust controller design that accounts for variations in operational points and grid changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If decentralized converter-based generators (wind power installations) are used to support the electrical supply grid, then grid stability can be improved, but the changing network properties make detection and damping of low-frequency oscillations more difficult
Solution Approach 1:
The damping controller is designed in advance to cover the entire frequency range of low-frequency oscillations (0.1-10 Hz) without requiring real-time detection. The controller proactively prevents weakly damped modes by using a broad frequency response characteristic, eliminating the need for subsequent oscillation detection and adaptation.
Solution Approach 2:
The damping controller is designed with universal applicability across the entire low-frequency spectrum (0.1-10 Hz) rather than targeting specific frequencies. This multi-functional design allows the controller to handle various oscillation modes and changing network conditions with a single robust controller, making the system adaptable without requiring active detection.
2Adaptability or versatility
If a robust controller design covering the entire frequency range is used, then adaptability to changing network properties is improved, but controller complexity increases
Solution Approach 1:
The controller parameters are predetermined during the design phase to cover the entire frequency range of low-frequency oscillations. This preliminary configuration provides robust adaptability to changing network conditions without requiring complex real-time adjustment mechanisms or active oscillation detection systems.
Solution Approach 2:
The damping controller uses feedback from the electrical supply grid voltage to automatically adjust the feed-in of electrical power. This feedback mechanism enables the controller to respond to changing network conditions and damp oscillations passively, reducing the need for complex detection and manual adjustment systems.
3Reliability
If the damping controller controls the feed-in of electrical power, then low-frequency oscillations are damped, but the precision of power feed-in control must be increased
Solution Approach 1:
The damping controller uses feedback from the electrical supply grid voltage to automatically adjust the feed-in of electrical power. This closed-loop control mechanism enables precise power control by continuously monitoring grid conditions and adjusting the feed-in accordingly, ensuring effective oscillation damping while maintaining control precision.
Data Source
AI summary
Provided is a method for controlling a wind power system, that is to say a wind power installation or a wind farm comprising a plurality of installations, for feeding electrical power from wind into an electrical supply grid, and for damping low-frequency oscillations, in particular subsynchronous resonances, in the grid, wherein the grid has a line voltage with a nominal line frequency, wherein a damping control with a closed control circuit is used for damping the low-frequency oscillations, and the damping control for damping the low-frequency oscillations controls a feed-in of electrical power into the grid using a wind system control, the damping control is designed for a controlled system comprising the grid, the wind power system, and the wind system control, or parts thereof, wherein the damping control is designed such that it prevents and/or damps weakly damped modes in the closed control circuit.