Wind Farm Power Control for Subsynchronous Oscillation Damping
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Solution Overview
Problem
Low-frequency oscillations in electrical supply networks, such as subsynchronous resonances, can cause damage to synchronous generators and lead to partial mains shutdowns or blackouts, and existing solutions struggle to effectively adapt to changing network conditions and properties.
Innovation Solution
A method for controlling wind farms to dampen low-frequency oscillations by detecting vibration characteristics through measurements, specifying active or reactive power damping signals, and adjusting power feed-in based on network and oscillation characteristics to shift the operating point of the electrical supply network, thereby stabilizing it.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If wind farms use fixed control strategies for damping oscillations, then implementation is simple, but they cannot adapt to changing network conditions and properties
Solution Approach 1:
The control strategy transitions from static to dynamic by continuously monitoring network conditions (impedance, oscillation frequency, amplitude) and adapting the damping control parameters in real-time. The wind farm control system adjusts its behavior based on changing network topology and operating conditions, making the system dynamically responsive rather than fixed.
Solution Approach 2:
The invention implements a feedback mechanism where the wind farm continuously measures network oscillations and impedance characteristics, processes this information through a control algorithm, and adjusts the active and reactive power output accordingly. This closed-loop feedback enables automatic adaptation to changing network conditions without manual intervention.
2Reliability
If wind farms implement real-time detection and adaptive control of oscillations, then damping effectiveness improves, but control system complexity increases
Solution Approach 1:
The wind farm control system performs multiple functions: it generates active power, generates reactive power, detects network oscillations, measures network impedance, and implements damping control. By consolidating these diverse functions into a single integrated control platform, the invention avoids the need for separate dedicated devices for each function, thereby managing complexity while achieving reliable damping.
Solution Approach 2:
The wind farm uses its own power electronics and control systems to detect and dampen oscillations, rather than relying on external dedicated damping devices. The wind farm essentially serves its own grid support function, using its active and reactive power capabilities to stabilize the network without requiring additional specialized equipment.
3Object-affected harmful factors
If wind farms adjust active and reactive power output dynamically, then oscillation damping improves, but impact on power generation and network stability becomes more complex
Solution Approach 1:
The invention changes the operating parameters of the wind farm by dynamically adjusting the active power (P) and reactive power (Q) output. The control system modulates these power parameters in response to detected oscillations, using parameter variation as the primary mechanism for achieving damping while managing the complexity of power output control.
Data Source
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AI summary
The invention relates to a method for controlling a wind farm (112) in order to damp low-frequency electrical oscillations, in particular subsynchronous resonances, in an electrical supply grid (306), the supply grid (306) having a grid voltage with a nominal grid frequency, the wind farm (112) comprising at least one wind turbine (100, 300) connected to the electrical supply grid (306), comprising the steps: sensing at least one low-frequency electrical oscillation of the electrical supply grid; determining an oscillation characteristic of each of the at least one sensed oscillation, the oscillation characteristic describing at least one property of the sensed oscillation; specifying an active-power damping signal (ΔP) and/or a reactive-power damping signal (ΔQ) for damping the at least one low-frequency oscillation characterized by the oscillation characteristic; feeding in an active power component in accordance with the active-power damping signal or a reactive power component in accordance with the reactive-power damping signal, the active-power damping signal (ΔP) and the reactive-power damping signal (ΔQ) being specified in dependence on the determined oscillation characteristic.