Leaky Feeder TDR Calibration for Noise-Robust Wind Turbines
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Solution Overview
Problem
There is a need for an efficient and reliable method to calibrate a leaky feeder path, particularly in wind turbines, without relying on signal transmission over the air, as existing methods are not effective in non-radar applications and can be prone to external radio frequency noise.
Innovation Solution
A calibration device comprising a leaky feeder with slots, an elongated conductor connected to a transmitter and receiver, and a processing device that uses time domain reflectometry to transmit and receive electromagnetic signals within the leaky feeder path, allowing for calibration without signal transmission over the air.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If signal transmission over the air is used for calibration, then calibration can be performed using conventional radar functionality, but the system becomes prone to external radio frequency noise and is not effective in non-radar applications
Solution Approach 1:
The invention extracts the calibration function from the air-based radar signal transmission and relocates it to the leaky feeder cable itself. By using the leaky feeder as a waveguide for electromagnetic signals, the calibration process is separated from the external air environment that introduces RF noise, enabling reliable calibration in non-radar applications while maintaining adaptability.
Solution Approach 2:
The leaky feeder cable serves as an intermediary medium between the signal source and the target area. Instead of transmitting calibration signals directly through the air, the signals are guided through the leaky feeder structure, which acts as a controlled intermediate path that eliminates external noise interference while maintaining signal integrity for calibration purposes.
2Measurement precision
If conventional radar signal transmission over air is used, then calibration can be performed, but the calibration accuracy is compromised due to noise and lack of established solutions for non-radar applications
Solution Approach 1:
The invention replaces the mechanical/electromagnetic wave propagation through air with guided electromagnetic wave propagation through the structured leaky feeder cable. This substitution provides a controlled transmission path with known characteristics, enabling accurate time domain reflectometry measurements and reliable calibration without the uncertainties of air-based signal transmission.
3Object-affected harmful factors
If time domain reflectometry is implemented within the leaky feeder path, then external noise resistance is improved, but the device complexity increases due to additional components
Solution Approach 1:
The leaky feeder cable is designed to serve multiple functions: it acts as both the antenna/radiating element for radar applications and as a waveguide for time domain reflectometry calibration. This multi-functionality eliminates the need for separate calibration hardware, reducing overall device complexity while maintaining robust noise resistance through the integrated calibration capability.
Solution Approach 2:
The leaky feeder system performs self-calibration through time domain reflectometry using its own structure as the transmission medium. The system uses itself as both the object to be calibrated and the calibration tool, eliminating the need for external calibration equipment and reducing device complexity while ensuring reliable noise-resistant calibration.
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 method enables accurate determination of length and phase information, is robust to external noise, and simplifies the calibration process by using time domain reflectometry to perform self-tests within the leaky feeder path, reducing technical effort and costs.
Implementation Method 1
a transmitter (unit, e.g. a pulse generator), coupled to the (lead-in) elongated conductor, and configured to transmit an electromagnetic signal (in particular a pulse or a wave) through the elongated conductor (and through) to the leaky feeder
Implementation Method 2
a receiver (unit, e.g. an A/D converter), coupled to the (lead-in or lead-out) elongated conductor (and/or to the leaky feeder) and/or configured to receive a) the incident (direct, reflection-free) electromagnetic signal and/or b) a reflection of the electromagnetic signal, reflected (with)in the at least one elongated conductor and/or the leaky feeder
Data Source
Figure 1
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Figure 4~5
AI summary
There is described a calibration device (100), in particular for a wind turbine (1), comprising: i) a leaky feeder (110); ii) an elongated conductor (120), in particular a lead-in and/or a lead-out cable, connected to the leaky feeder (110); iii) a transmitter (131), coupled to the elongated conductor (120), and configured to transmit an electromagnetic signal, in particular a pulse, through the elongated conductor (120) to the leaky feeder (110); iv) a receiver (132), coupled to the elongated conductor (120) and/or to the leaky feeder (110), and configured to receive the electromagnetic signal directly and/or as a reflection; and v) a processing device (140), configured to perform a calibration operation based on the reception of the received signal.