Reactive Power Controller Damping Electromechanical Oscillations
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Solution Overview
Problem
Existing methods for damping electromechanical oscillations in power systems are inadequate, particularly as they can amplify or fail to dampen oscillations effectively, leading to instability and potential blackouts, especially in wind farms with standard control settings.
Innovation Solution
A method and wind farm design that utilize a reactive power controller to inject reactive power, with a switchable damping mechanism triggered by frequency and amplitude thresholds to compensate for controller dynamics and delays, ensuring stable system voltage and damping of electromechanical oscillations without interfering with normal operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If reactive power injection is used to damp electromechanical oscillations, then system stability is improved, but controller delays and dynamics may amplify oscillations instead of damping them
Solution Approach 1:
The oscillation detection unit detects electromechanical oscillations before they can be amplified by controller delays. The lead-lag compensation unit applies preliminary phase compensation to the damping signal to counteract the expected delay effects, ensuring the damping action remains effective despite controller dynamics.
Solution Approach 2:
The system continuously monitors system voltage and detects oscillations in real-time. The lead-lag compensation unit adjusts the damping signal based on feedback about the oscillation characteristics, dynamically compensating for controller delays and ensuring stable damping action.
2Ease of operation
If standard control settings are used in wind farms, then ease of operation is maintained, but electromechanical oscillations may be amplified leading to instability
Solution Approach 1:
The system dynamically switches between standard control operation and oscillation damping mode. The oscillation detection unit continuously monitors for oscillations, and when detected, the system automatically activates the lead-lag compensation and damping injection, providing adaptive behavior that maintains stability without requiring manual intervention.
Solution Approach 2:
The wind farm control system performs self-diagnosis by detecting oscillations autonomously and self-corrects by automatically activating the damping control. The oscillation detection unit and lead-lag compensation unit work together to provide self-service oscillation damping without external intervention, maintaining both ease of operation and system stability.
3Reliability
If damping control is continuously active, then oscillation damping is maintained, but interference with normal controller dynamics occurs
Solution Approach 1:
The damping control operates periodically rather than continuously. The oscillation detection unit detects when oscillations are present, and the damping control is activated only during these periods. This periodic activation maintains oscillation damping when needed while avoiding interference with normal controller dynamics during steady-state operation.
Solution Approach 2:
The system applies damping control partially - only when oscillations are detected - rather than continuously. This partial action approach provides sufficient damping during oscillation events while minimizing interference with normal controller operations, achieving the desired effect with reduced complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively attenuates electromechanical oscillations, preventing instability and amplification, ensuring system stability and reducing the risk of blackouts by compensating for controller dynamics and delays, while maintaining compliance with grid code requirements.
Implementation Method 1
damping of electromechanical oscillations by injecting reactive power generated by one or more wind energy turbines into the power system
Data Source
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AI summary
Method of damping electromechanical oscillations on a power system by injecting reactive power generated by one or more wind energy turbines, wherein a reactive power controller is adapted to determine a reference reactive power value (Qref) depending on an actual system voltage (Umeas), the method comprising: - measuring oscillation data associated with the power system, - filtering the measured oscillation data to remove a steady state offset, - determining a frequency value and an amplitude value from the filtered oscillation data, and - triggering a damping according to at least one of the following: o the frequency value determined from the filtered oscillation data falling within a predetermined frequency interval, and o the amplitude value determined from the filtered oscillation data exceeding a predetermined threshold value, - wherein the damping of the electromechanical oscillations on the power system is achieved by compensating a gain and a delay applied by the reactive power controller to the reference reactive power value (Qref).