Method and apparatus for detecting low-frequency oscillations
AssigneeWobben Properties GmbH
InventorAramis SCHWANKA TREVISAN
Life of this patent
Estimating the term…
Abstract
Provided is a method for detecting low-frequency oscillations, in particular subsynchronous resonance, in an electrical supply grid, wherein the electrical supply grid has a grid voltage at a grid nominal frequency, comprising the steps of capturing at least one electrical signal from the electrical supply grid, and evaluating the electrical signal by means of wavelet analysis, during which a time-dependent frequency pattern is created by analyzing a correlation of the captured signal with a predetermined wavelet mother function, wherein the presence of a low-frequency oscillation is assumed if at least one further low-frequency frequency component is present in the time-dependent frequency pattern in addition to a fundamental component.
Claims21
A method for detecting low-frequency oscillations in an electrical supply grid having a grid voltage associated with a nominal frequency, comprising:
- capturing at least one electrical signal from the electrical supply grid;
- evaluating the at least one electrical signal using wavelet analysis, evaluating the at least one electrical signal using the wavelet analysis including:
- generating a time-dependent frequency pattern based on analyzing a correlation between the at least one electrical signal and a wavelet mother function;
- detecting a presence of a low-frequency component and a fundamental component in the time-dependent frequency pattern;
- and
- in response to detecting the presence of the low-frequency component and the fundamental component in the time-dependent frequency pattern, determining that a low-frequency oscillation is present.
A detection device for detecting low-frequency oscillations in an electrical supply grid having a grid voltage and an associated a grid nominal frequency, comprising:
- a sensor configured to capture at least one electrical signal from the electrical supply grid;
- and
- a controller configured to:
- evaluate the at least one electrical signal using wavelet analysis, evaluating the at least one electrical signal using the wavelet analysis including:
- generating a time-dependent frequency pattern based on analyzing a correlation between the at least one electrical signal and a predetermined wavelet mother function;
- detect a presence of at least one low-frequency component and a fundamental component in the time-dependent frequency pattern;
- and
- in response to detecting the presence of the low-frequency component and the fundamental component in the time-dependent frequency pattern, determine that a low-frequency oscillation is present.
(canceled)
A wind power installation or wind farm configured to supply electrical power to an electrical supply grid and to be connected to the electrical supply grid at a grid connection point, the wind power installation or wind farm comprising:
- a controller configured to:
- detect low-frequency oscillations in the electrical supply grid, wherein the electrical supply grid has a grid voltage and is associated with a grid nominal frequency, and the low-frequency oscillations to be detected have a lower frequency than the grid nominal frequency;
- and
- a sensor configured to at least one electrical signal from the electrical supply grid,
- wherein the controller is configured to:
- evaluate the at least one electrical signal using wavelet analysis, evaluating the at least one electrical signal using the wavelet analysis including:
- generating a time-dependent frequency pattern based on analyzing a correlation between the at least one electrical signal and a predetermined wavelet mother function;
- detecting a presence of a low-frequency component and a fundamental component in the time-dependent frequency pattern;
- and
- in response to detecting the presence of the low-frequency component and the fundamental component in the time-dependent frequency pattern, determining that a low-frequency oscillation is present.
(canceled)
Dependencies are inferred from the claim text.