Electronic Tap-Changing Transformer Control for Wind Turbine Grid Voltage
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Solution Overview
Problem
Wind turbines face challenges in meeting strict grid code requirements for voltage variations, leading to increased costs and reduced power generation capabilities, while also experiencing mechanical stress due to grid voltage fluctuations.
Innovation Solution
A method of controlling a wind turbine transformer using an electronic on-load tap changer with semiconductor switches, which adjusts the turns ratio in response to voltage changes on the primary or secondary side, allowing for quick compensation of voltage variations and maintaining a stable voltage on the secondary side.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the wind turbine electrical system is adapted and oversized to handle voltage variations, then the wind turbine can meet grid code requirements, but the cost increases and power generating capabilities are reduced
Solution Approach 1:
The patent applies dynamics by implementing an electronic on-load tap changer that dynamically adjusts the transformer turns ratio in response to grid voltage variations. This allows the wind turbine electrical system to adapt to changing voltage conditions without requiring oversized components, thereby maintaining reliability while preserving power generating capabilities
Solution Approach 2:
The patent changes the transformer turns ratio parameter dynamically through electronic tap changing. By adjusting this parameter in response to voltage variations, the system can meet grid code requirements without oversizing, thus avoiding the trade-off between reliability and productivity
2Reliability
If flexible AC transmission systems (FACTS) and reactive power compensation equipment are installed to meet grid code requirements, then voltage regulation capability is improved, but the cost increases significantly
Solution Approach 1:
The patent makes the wind turbine transformer multi-functional by equipping it with an electronic on-load tap changer that performs both voltage transformation and voltage regulation. This eliminates the need for separate FACTS and reactive power compensation equipment, reducing device complexity while maintaining voltage regulation capability
Solution Approach 2:
The patent merges the voltage regulation function into the transformer itself through the electronic tap changer. By combining what would traditionally require separate FACTS equipment into the transformer, the system achieves voltage regulation without significant additional cost or complexity
3Reliability
If the wind turbine uses pitch control to deal with mechanical stress from grid voltage variations, then mechanical fatigue is reduced, but the electrical power output optimization is interfered with
Solution Approach 1:
The patent extracts the voltage variation compensation function from the mechanical pitch control system and places it in the electrical domain through the electronic tap changer. This allows pitch control to focus solely on optimizing electrical power output while the tap changer handles voltage variations, eliminating the interference between the two functions
4Reliability
If conventional tap changers are used in the transformer, then voltage compensation is possible, but the response time is too slow to meet strict grid code requirements
Solution Approach 1:
The patent replaces the mechanical tap changer system with an electronic on-load tap changer using semiconductor switches. This substitution dramatically increases the response speed from mechanical timescales to electronic timescales, enabling the system to meet strict grid code requirements for HVRT and LVRT while maintaining voltage compensation capability
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 solution enables wind turbines to operate efficiently and cost-effectively by reducing the need for oversized components, minimizing mechanical stress, and maximizing reactive power generation capabilities, while ensuring compliance with high voltage ride through (HVRT) and low voltage ride through (LVRT) requirements.
Implementation Method 1
a wind turbine transformer having a primary side with a primary winding coupled to a power grid and a secondary side with a secondary winding coupled to an electrical power generating system of the wind turbine
Data Source
AI summary
A method of controlling a wind turbine transformer is provided. The transformer has a primary side with a primary winding coupled to a power grid and a secondary side with a secondary winding coupled to an electrical power generating system of the wind turbine. The wind turbine transformer further includes an electronic on-load tap changer having semiconductor switches that are controllable to change a turns ratio of the primary winding to the secondary winding of the wind turbine transformer. The method includes the step of monitoring a voltage on the primary side of the wind turbine transformer, a voltage on the secondary side of the wind turbine transformer, or both. In response to detecting a change in the monitored voltage, the semiconductor switches of the electronic on-load tap changer are automatically controlled to adjust the turns ratio of the wind turbine transformer to compensate for the change.