Wind Turbine Transformer Inrush Current Reduction
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Solution Overview
Problem
Wind turbines face challenges during maintenance when disconnected from the grid, as reconnection can cause high inrush currents that may damage transformers and electronic components, and existing solutions are not cost-effective.
Innovation Solution
A wind turbine system that includes a service voltage transformer to supply power to selected components when the main transformer is disconnected, and a pre-charge circuit to pre-energize the main transformer before reconnection, reducing inrush currents and mechanical loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the main transformer is disconnected from the grid for maintenance, then safety and maintenance capability are improved, but power supply to electrical components is lost
Solution Approach 1:
The patent segments the power supply system into two independent paths: the main transformer path for normal operation and the service transformer path for maintenance. This allows the main transformer to be disconnected for maintenance while the service transformer continues to supply power to critical electrical components, resolving the contradiction between maintenance safety and power supply availability.
2Productivity
If the main transformer is reconnected to the grid after disconnection, then normal operation is restored, but high inrush currents occur that can damage the transformer and electronic components
Solution Approach 1:
The patent employs a pre-charge circuit that activates before the main transformer is reconnected to the grid. This circuit gradually charges the transformer windings and associated capacitors to the grid voltage level, ensuring that when the main breaker closes, there is minimal voltage difference and thus minimal inrush current. This preliminary action protects the transformer and electronic components from damage while restoring normal operation.
3Use of energy by moving object
If auxiliary power generators are installed to supply power during maintenance, then power supply availability is improved, but system complexity and cost increase
Solution Approach 1:
The service transformer is designed with multi-functionality: it serves as a backup power source during maintenance operations and can also support critical loads during normal operation if needed. By making the service transformer universal rather than dedicated solely to maintenance, the system avoids the need for separate auxiliary generators, thereby reducing system complexity and cost while maintaining power supply availability.
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 system effectively provides power to critical components during maintenance, reduces inrush currents, and extends transformer life by pre-magnetizing the transformer before reconnection, thereby minimizing mechanical loads and oscillations.
Implementation Method 1
pre-energizing a secondary winding of the main transformer with the pre-charge circuit while a primary winding of the transformer is disconnected from the grid
Implementation Method 2
one or more of the wind turbine electrical components are configured to be connected to the auxiliary wind turbine transformer and a selection of the wind turbine electrical components is further configured to be connected to the busbar through a service voltage transformer
Data Source
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AI summary
A wind turbine is provided. The wind turbine comprises: a generator (162), one or more power converters (20) arranged between the generator and a point of connection to a main transformer (5), and one or more wind turbine electrical components (8, 9, 10). The main transformer (5) is configured to connect a busbar (60) to an auxiliary wind turbine transformer, wherein the busbar is configured to receive electrical power from an electrical grid with a main voltage. The wind turbine electrical components are configured to be connected to the auxiliary wind turbine transformer (6), wherein a selection of the wind turbine electrical components is further configured to be connected to the busbar through a service voltage transformer (7) when the main transformer (5) is disconnected from the busbar. Systems comprising such wind turbines are also provided. Methods for connecting a wind turbine main transformer to a grid are also provided.