Wind Farm Reactive Power Control with Turbine Voltage Setpoints
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Solution Overview
Problem
Existing methods for distributing reactive power among wind turbines in a wind farm often result in asymmetry due to varying sizes and power generation levels, leading to inappropriate distribution and voltage differences, which can affect grid stability and efficiency.
Innovation Solution
A method for controlling reactive power distribution in a wind farm by determining an individual system voltage setpoint for each turbine based on a common voltage setpoint and considering the relationship with other turbines' reactive powers, using a PI controller to achieve symmetry and adjust reactive current generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If reactive power is distributed evenly among all wind turbines, then the control is simple, but the distribution becomes inappropriate when turbines have different sizes or power generation levels
Solution Approach 1:
The patent applies local quality by assigning different voltage setpoints to different wind turbines based on their individual characteristics and operating conditions. Instead of uniform reactive power distribution, each turbine receives a customized voltage setpoint that accounts for its specific size, power generation level, and local grid conditions, thereby achieving appropriate distribution without complex centralized control
2Manufacturing precision
If individual reactive power values are specified for each wind turbine, then the distribution can be optimized, but asymmetry and voltage differences between turbines increase
Solution Approach 1:
The patent applies equipotentiality by using a common reference voltage that all wind turbines share. Each turbine's voltage setpoint is derived from this common reference, ensuring that while individual reactive power values differ, they all reference the same baseline. This maintains system symmetry and prevents excessive voltage differences between turbines, as all turbines are effectively at the same electrical potential reference
3Power
If the farm voltage setpoint is adjusted to meet reactive power targets, then the overall reactive power provision improves, but voltage differences between turbines vary due to different cable lengths and asymmetries
Solution Approach 1:
The patent applies local quality by adding individual voltage offsets to each turbine's setpoint based on its specific characteristics such as cable length and location. When the farm voltage setpoint is adjusted to meet reactive power targets, each turbine experiences this adjustment plus its local offset, compensating for differences in cable lengths and asymmetries to maintain more uniform voltages across all turbines
Data Source
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AI summary
The invention relates to a method for providing a park reactive power by a wind farm comprising several wind turbines, comprising the steps of receiving a park reactive power setpoint as a specification of a reactive power to be fed in by the wind farm, determining a park voltage setpoint as a common voltage setpoint for all wind turbines depending on the park reactive power setpoint, determining an individual system voltage setpoint for each of the wind turbines depending on the park voltage setpoint,Determining and delivering an individual system reactive power or an individual reactive current by each of the wind turbines as a function of a system voltage difference as the difference between an actual system voltage and the individual system voltage setpoint of the respective wind turbine, and wherein the individual system voltage setpoint is determined in each case as a function of the individual system reactive power of the respective wind turbine and as a function of several, in particular all, individual system reactive powers of the wind turbines of the wind farm.