Acoustic Corona Detection Using Harmonic Frequency Analysis
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Solution Overview
Problem
Conventional methods for detecting corona on power transmission lines are costly, cumbersome, and lack accuracy due to reliance on ultraviolet and ultrasonic detection, which are affected by environmental conditions and require manual operation.
Innovation Solution
A system that processes audio data from near electrical conductors using a fundamental frequency corresponding to the AC power signal and selected harmonic frequencies to detect corona, employing thresholds and normalization to identify corona events, with the ability to communicate alerts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ultraviolet and ultrasonic detection methods are used for corona detection, then detection capability is provided, but cost increases and operation becomes cumbersome
Solution Approach 1:
The patent replaces complex mechanical detection systems (ultraviolet cameras, ultrasonic detectors) with an acoustic detection system that uses microphones and signal processing. The corona detection is achieved by analyzing audio frequencies generated by corona discharges, substituting mechanical/optical systems with a simpler acoustic field-based system that processes sound waves in the frequency range of 20 Hz to 20 kHz.
Solution Approach 2:
The patent employs inexpensive audio recording devices and microphones instead of costly ultraviolet detection equipment. By using standard audio technology and processing methods, the system achieves corona detection at a fraction of the cost of conventional methods, making the detection capability accessible and economically viable.
2Reliability
If conventional ultraviolet detection is used, then corona can be detected, but manual operation is required and accuracy decreases due to environmental conditions
Solution Approach 1:
The patent implements autonomous corona detection through automated audio recording and analysis. The system automatically captures audio data, processes it through frequency analysis algorithms, and generates detection results without requiring manual operation. The processor autonomously identifies corona-related frequency patterns, eliminating the need for human operators to manually aim and operate detection equipment.
Solution Approach 2:
The system incorporates automated feedback mechanisms where the processor continuously analyzes audio frequency data and adjusts detection parameters based on identified patterns. The system provides real-time feedback on corona detection status, automatically correlating acoustic signals with corona events and providing continuous monitoring without environmental interference.
3Measurement precision
If audio data processing with harmonic frequency analysis is used, then detection accuracy improves, but data processing complexity increases
Solution Approach 1:
The patent segments the audio frequency spectrum into distinct frequency bands and harmonic components for analysis. By dividing the complex audio signal into manageable frequency segments (fundamental frequency and harmonic frequencies), the system can process each segment separately using targeted algorithms, improving detection precision while keeping individual processing tasks computationally efficient.
Solution Approach 2:
The system transforms the audio detection problem by changing the analysis parameters from time-domain to frequency-domain analysis. By applying Fast Fourier Transform (FFT) and analyzing specific frequency parameters (harmonics of the power frequency), the system converts complex temporal audio patterns into simplified frequency signatures that are easier to process and correlate with corona events.
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 approach provides a cost-effective, accurate, and autonomous method for detecting corona, enabling preventative maintenance and reducing repair costs with faster analysis and communication of data across large geographic areas.
Implementation Method 1
obtaining audio data by an audio detector deployed to detect corona generated by an alternating current (AC) system
Implementation Method 2
processing the audio data using a fundamental frequency corresponding to the AC power signal in the conductor and a selected number of harmonic frequencies of the audio data
Data Source
AI summary
Apparatuses, systems and methods for detecting corona using audio data are disclosed. A method of processing audio data to detect corona includes determining an indicator of energy at a substantially fundamental frequency in the audio data, determining an indicator of the energy at a plurality of harmonic frequencies in the audio data, determining an indicator of the noise energy in the audio data, determining a comparison indicator of the noise energy relative to the energy at the harmonic frequencies, determining a masking indicator having thresholds for each of the harmonics relative to the fundamental frequency, and determining a corona detection indicator. An apparatus for detecting corona includes a memory, an audio detector configured to obtain the audio data near an electrical conductor in an AC system, and a processor to process the audio data, fundamental and harmonic frequencies of the audio data and their corresponding thresholds to detect corona.