Low-Voltage Tertiary Winding Harmonic Filter for Wind Turbines
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Solution Overview
Problem
Wind power systems generate unwanted voltage and current harmonics due to variable speed operation, which can interfere with the power supply grid, and existing solutions require high-voltage harmonic filters that are costly and physically large.
Innovation Solution
A wind turbine facility with a grid transformer having a tertiary winding connected to a harmonic filter system, where the turn ratio between primary and tertiary windings is set to operate at a lower voltage level, allowing for the use of passive or active filters to suppress selected harmonics, such as the eleventh, thirteenth, seventeenth, nineteenth, twenty-third, and twenty-fifth harmonics, at a significantly lower voltage level, reducing costs and filter size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high-voltage harmonic filters are used to suppress harmonics in wind power systems, then harmonic suppression effectiveness is improved, but filter size and cost increase significantly
Solution Approach 1:
The patent introduces a tertiary winding with a different voltage level dimension (lower voltage) to connect the harmonic filter, transforming the filter operation from high-voltage to low-voltage domain. This dimensional change in voltage level allows the same harmonic suppression function to be achieved with much smaller and cheaper filter components.
Solution Approach 2:
The patent applies local quality by creating a localized low-voltage environment through the tertiary winding specifically for the filter connection, while the main system continues to operate at high voltage. This localized transformation allows the filter to operate under favorable low-voltage conditions without affecting the overall high-voltage power transmission.
2Reliability
If high-voltage harmonic filters are used to suppress harmonics in wind power systems, then harmonic suppression effectiveness is improved, but filter cost increases significantly
Solution Approach 1:
The patent introduces a tertiary winding with a different voltage level dimension (lower voltage) to connect the harmonic filter, transforming the filter operation from high-voltage to low-voltage domain. This dimensional change in voltage level allows the same harmonic suppression function to be achieved with much smaller and cheaper filter components.
Solution Approach 2:
The patent applies local quality by creating a localized low-voltage environment through the tertiary winding specifically for the filter connection, while the main system continues to operate at high voltage. This localized transformation allows the filter to operate under favorable low-voltage conditions without affecting the overall high-voltage power transmission.
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 solution effectively suppresses harmonics at a lower voltage level, reducing the size and cost of the harmonic filter system while minimizing interaction with the power supply grid, and allows for more efficient harmonic filtering using either passive or active filters, depending on the configuration.
Implementation Method 1
tuned LC-branches on the high voltage side of the step-up transformer
Implementation Method 2
grid transformer comprising one or more primary windings being operationally connected to the AC/AC converter
Data Source
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AI summary
The present invention relates to a wind turbine facility comprising a power generator operationally connected to an AC/AC converter adapted to receive variable frequency AC-power from the power generator, and adapted to generate substantially fixed frequency AC-power. The wind turbine facility further comprises a harmonic filter system, and a grid transformer comprising a primary winding being operationally connected to the AC/AC converter, and a secondary winding adapted to be operationally connected to an associated, substantially fixed frequency AC-power supply grid. The grid transformer further comprises a tertiary winding being operationally connected to the harmonic filter in order to suppress unwanted harmonics, such as selected harmonics generated by the AC/AC converter. The turn ratio between the primary and tertiary windings is selected in such a manner that a voltage of the tertiary winding is lower than a nominal voltage level of the associated AC-power supply grid voltage.