Partial Discharge Detection Using Dual-Band Signal Segmentation
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Solution Overview
Problem
Current methods for detecting partial electrical discharges face challenges in interpreting results due to unreliable data, loss of information, and the need for instruments with wide detection bandwidths that comply with standards, while also dealing with noise interference and limited sensitivity.
Innovation Solution
An instrument with two acquisition channels, a broadband HF channel and a narrowband LF channel, where the LF channel is controlled by the HF channel's trigger and includes a time-delay unit for signal compensation, allowing for effective pulse matching and noise cancellation, ensuring high sensitivity and compliance with standards.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If a wide detection bandwidth is used to capture complete discharge pulse information, then diagnostic information completeness is improved, but measurement precision deteriorates due to inability to comply with standards and compare results
Solution Approach 1:
The patent divides the detection system into two separate acquisition channels: a first channel with wide bandwidth (at least 20 MHz) for capturing complete discharge pulse information, and a second channel with narrow bandwidth (less than 500 kHz) for obtaining measurements compliant with standards. This segmentation allows each channel to specialize in one function, resolving the contradiction between information completeness and measurement comparability.
2Measurement precision
If a narrowband filter is applied to comply with standards, then measurement comparability is improved, but loss of information increases due to filtering out high-frequency components
Solution Approach 1:
The patent creates separate acquisition channels for different bandwidth requirements. The first channel operates with wide bandwidth to capture all discharge information without filtering, while the second channel applies narrowband filtering to achieve standard compliance. This eliminates the need to choose between information preservation and standard compliance.
Solution Approach 2:
The patent introduces a processing unit that acts as an intermediary between the two acquisition channels. It receives data from both channels, correlates the wideband information with the narrowband standardized measurements, and produces integrated diagnostic results that satisfy both information completeness and standard comparability requirements.
3Reliability
If broadband acquisition is used to detect all discharge signals, then sensitivity is improved, but noise interference increases making detection difficult
Solution Approach 1:
The patent segments the detection function into two channels: the first channel uses wide bandwidth for high sensitivity detection of all discharge signals, while the second channel uses narrow bandwidth to reject high-frequency noise and provide cleaner reference measurements. This segmentation allows the system to benefit from both high sensitivity and noise rejection.
Solution Approach 2:
The processing unit implements feedback by continuously comparing and correlating data from both acquisition channels. The narrowband channel provides feedback about noise characteristics and baseline conditions, which is used to filter and refine the broadband detection results, thereby reducing noise interference while preserving sensitivity.
Data Source
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AI summary
An instrument (1) and a method for detecting partial electric discharges involve acquiring a discharge signal (10), for example picked up by a direct- measuring impedance device (7) through a broadband HF acquisition channel (18), and acquiring the discharge signal (10) in a narrowband LF acquisition channel (180) complying with regulations, using on the LF acquisition channel (180) a trigger controlled in slave mode by a trigger of the broadband HF acquisition channel (18); they also involve acquiring another discharge signal (32) picked up by an indirect-measuring impedance device (8) through a second narrowband LF acquisition channel (180A) and comparing digital signals (34, 34A) generated in the first and second LF acquisition channels (180, 180A), in order to generate a balanced digital signal (36) without components representative of common mode electrical signals present in the measuring circuit.