Wind Turbine Reactive Power Control for Generator Stability
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Solution Overview
Problem
Conventional power plants with synchronous generators become unstable due to changes in the electrical supply network, particularly during load switching operations, leading to suboptimal or unstable operating points and underexcitation.
Innovation Solution
A method for controlling wind turbines or wind farms to exchange reactive power with the electrical supply network, determining the reactive power requirement, and adjusting the exchange to support conventional power plants, preventing underexcitation by consuming reactive power when necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If load switching operations are carried out in the electrical supply network, then the network state changes to meet varying demand, but the synchronous generator in the conventional power plant becomes unstable and slips into suboptimal operating points
Solution Approach 1:
The wind turbine applies preliminary anti-action by detecting the reactive power requirement of the electrical supply network in advance and adjusting its reactive power output accordingly. This prevents the synchronous generator from entering unstable operating points by counteracting the effects of load switching operations before they cause instability.
Solution Approach 2:
The wind turbine acts as an intermediary between the electrical supply network and the synchronous generator. By adjusting its reactive power output based on the network's reactive power requirement, it mediates the impact of network state changes on the synchronous generator, preventing instability while allowing the network to adapt to varying demand.
2Device complexity
If the synchronous generator operates with limited operating range, then the design remains simple and cost-effective, but the generator becomes unstable when forced into underexcitation by reactive power oversupply
Solution Approach 1:
The wind turbine serves as an intermediary that compensates for the synchronous generator's limited operating range. By adjusting its reactive power output, it prevents the generator from entering unstable underexcitation regions while maintaining the generator's simple and cost-effective design.
Solution Approach 2:
The wind turbine changes the reactive power parameter in the electrical supply network to maintain the synchronous generator within its stable operating range. By dynamically adjusting reactive power based on the network's requirements, it ensures the generator operates reliably without expanding the generator's own operating range or complexity.
3Reliability
If the wind turbine adjusts reactive power output to support the conventional power plant, then the synchronous generator remains stable, but the wind turbine must operate beyond its normal control range
Solution Approach 1:
The wind turbine uses feedback control by continuously monitoring the electrical supply network's reactive power requirement and adjusting its reactive power output accordingly. This feedback mechanism enables the wind turbine to support the synchronous generator's stability while operating within its designed control capabilities, without requiring excessive 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
This method stabilizes synchronous generators by maintaining them in an overexcited state, preventing underexcitation and ensuring stable operation during normal and fault conditions within the electrical supply network.
Implementation Method 1
a wind energy installation or a wind farm, in particular comprising a large number of wind power plants 1000 connected to one another in parallel, having a control unit with a subordinate regulation for determining an electrical active and/or reactive power to be exchanged with the electrical supply network 2000 and a higher-level regulation for determining an electrical power to be exchanged with the electrical supply network 2000, wherein the reactive power to be exchanged is determined as a function of a reactive power requirement of the electrical supply network 2000
Data Source
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AI summary
The present invention relates to a method for controlling a wind turbine or a wind farm, comprising the steps of: exchanging electrical active and/or reactive power at a grid connection point with an electrical supply network which includes a conventional power plant; determining a reactive power demand of the electrical supply network; changing the exchange of electrical reactive power at the grid connection point with the electrical supply network depending on the reactive power demand of the electrical supply network in order to support the conventional power plant.