High-Frequency AC Testing for Galvanic Connection Quality
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Solution Overview
Problem
Current methods for testing the quality of galvanic connections in high-voltage condenser bushing assemblies are inadequate for ensuring long-term reliability and often require real-life operating conditions, which can be unsafe and inefficient.
Innovation Solution
A capacitive test circuit using an AC power source to provide a high-frequency test current (10 kHz or higher) and a measurement unit to assess the resistance of the galvanic connection, allowing for the determination of connection quality without exposing the assembly to high operating voltages, thus ensuring safety and sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If real-life operating conditions are used for testing galvanic connections, then the testing method is simple and familiar, but the sensitivity and reliability of detecting connection quality are insufficient
Solution Approach 1:
The patent changes the test frequency parameter from standard power frequency (50/60 Hz) to high frequency (10 kHz or higher). This parameter change dramatically improves the sensitivity of detecting galvanic connection quality by utilizing the skin effect and proximity effect at high frequencies, which amplify the impact of connection resistance on the overall impedance measurement.
Solution Approach 2:
Instead of testing at low frequencies under normal operating conditions, the patent inverts the approach by testing at high frequencies. This inversion reveals connection defects more effectively because high-frequency currents are more sensitive to contact resistance and connection quality, allowing detection of soon-to-fail connections that would be missed at standard frequencies.
2Reliability
If high test frequencies (10 kHz or higher) are used, then the detection sensitivity and reliability are drastically improved, but the testing method departs from standard practices and requires specialized equipment
Solution Approach 1:
The patent employs parameter changes by operating the AC power source at high frequencies (10 kHz or higher) rather than standard power frequencies. This enables reliable detection of galvanic connection quality through enhanced sensitivity to connection resistance, while the measurement unit captures impedance or current data that reflects connection health.
Solution Approach 2:
The patent replaces traditional mechanical/electrical testing methods with an electromagnetic-based high-frequency AC testing approach. By using high-frequency AC current and measuring impedance or current response, the method substitutes conventional low-frequency resistance measurement with a more sensitive electromagnetic interaction technique that detects connection quality through field effects.
3Measurement precision
If standard low frequency testing is used, then the testing equipment is simple and familiar, but the method cannot reliably detect soon-to-fail connections
Solution Approach 1:
The patent changes the frequency parameter to 10 kHz or higher, which dramatically improves the accuracy of detecting connection quality and identifying soon-to-fail connections. The high-frequency AC test current interacts more strongly with connection resistance through skin effect and proximity effect, enabling precise detection of degradation that low-frequency methods miss.
Solution Approach 2:
The patent performs preliminary detection of connection defects by testing at high frequencies before failures occur. This preliminary action at elevated frequencies reveals early signs of connection degradation, allowing preventive maintenance before actual failures happen, thereby reducing downtime and loss.
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 effectively detects both good and soon-to-fail galvanic connections, preventing sudden failures and ensuring reliable operation while maintaining safety and reducing costs.
Implementation Method 1
providing, by the AC power source, a first test current in the capacitive test circuit. The first test current is an AC current at a first test frequency of 10 kHz or higher
Implementation Method 2
measuring, by the measurement unit, a test parameter indicative of a resistance of the galvanic connection
Data Source
AI summary
A method for testing the quality of a galvanic connection between a first terminal and a conductive layer of a high-voltage condenser bushing assembly is provided. The method includes providing a capacitive test circuit. The capacitive test circuit comprises the first terminal, an AC power source and a measurement unit. The method further includes providing, by the AC power source, a first test current in the capacitive test circuit. The first test current is an AC current at a first test frequency of 10 kHz or higher. The method further includes measuring, by the measurement unit, a test parameter indicative of a resistance of the galvanic connection. The method further includes determining the quality of the galvanic connection from the measured test parameter.