Wind Farm Voltage Control via Dynamic Transformation Ratio
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Solution Overview
Problem
Wind turbines in wind farms face increased load and reduced service life due to operating near system limits, leading to higher maintenance costs, as they must maintain electrical energy delivery within a narrow voltage range to avoid overloading and meet reactive power specifications.
Innovation Solution
The method involves dynamically adjusting the transformation ratio between the wind farm's internal and external voltage networks based on the electrical utilization of wind turbines, using a step switch and wind farm controller to set the transformation ratio, thereby reducing electrical load by altering the operating point on the U-Q characteristic diagram and managing reactive power reserves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the voltage in the wind farm's internal network is kept within a narrow range to avoid overloading, then the wind turbine can deliver nominal power and meet reactive power specifications, but the load on the wind turbine increases and service life is reduced
Solution Approach 1:
The invention applies dynamics by making the transformation ratio adjustable rather than fixed. The step switch enables the transformation ratio to be dynamically changed based on operating conditions, allowing the system to adapt between delivering nominal power and reducing turbine load, thus resolving the contradiction between reliability and productivity
Solution Approach 2:
The invention changes the transformation ratio parameter between the internal and external networks to resolve the contradiction. By adjusting this parameter, the system can operate at different points on the U-Q characteristic diagram, enabling either nominal power delivery or reduced load operation depending on the priority
2Duration of action of stationary object
If the transformation ratio is changed to reduce electrical load on wind turbines, then service life is extended, but the voltage in the internal network changes which requires compensation
Solution Approach 1:
The invention uses feedback control where the wind farm controller monitors the voltage in the internal network and automatically adjusts the transformation ratio or coordinates with wind turbine controllers to maintain voltage within acceptable ranges, thereby managing the complexity of voltage control while extending turbine service life
3Reliability
If the step switch is actuated to change transformation ratio, then the voltage in the internal wind farm network changes to reduce load, but switching operations cause wear and increase maintenance requirements
Solution Approach 1:
The invention implements periodic action by switching the transformation ratio only when necessary based on monitored operating conditions, rather than continuously or frequently. This reduces the number of switching operations and associated wear on the step switch, thereby reducing maintenance requirements while maintaining operational reliability
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 approach reduces the electrical load on wind turbines, extends their service life, and minimizes maintenance costs by optimizing voltage and reactive power management within the wind farm, ensuring efficient power delivery while adhering to reactive power specifications.
Implementation Method 1
the electrical energy is transformed to a voltage that is higher by a selectable transformation ratio than the voltage in the wind farm's internal network
Data Source
Figure 1
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AI summary
The invention relates to a method for operating a wind farm in which electrical energy generated in the wind farm is transported via an internal wind farm network (11) to a transfer station (12). Upon transfer to an external network (14), the electrical energy is transformed to a voltage that is higher than the voltage in the internal wind farm network (11) by a selectable transformation ratio. According to the invention, the electrical load of a wind turbine (10) in the wind farm is determined, and the transformation ratio is adjusted as a function of the electrical load of the wind turbine (10). The invention further relates to a wind farm with which the method according to the invention can be carried out. The invention makes it possible to influence the voltage in the internal wind farm network (11) in such a way that the wind turbines (10) operate at a lower electrical load.