Capacitor Bushing Monitoring via Acoustic Partial Discharge Detection
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Solution Overview
Problem
Existing methods for monitoring capacitor feedthroughs in AC networks are unreliable due to variations in measurement environments and operating conditions, such as temperature and operational stress, leading to inconsistent capacitance and loss factor measurements.
Innovation Solution
A method and device for monitoring capacitor feedthroughs that standardize characteristic values by using normalized capacitance calculations, accounting for environmental and operational differences through correction factors and reference voltage values, allowing for precise comparison with predetermined tolerances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional measurement methods (clamp-on current transformers, voltage taps) are used, then existing grid infrastructure can be utilized, but measurement precision and reliability are insufficient for detecting partial discharges and internal faults
Solution Approach 1:
The patent replaces conventional electrical measurement methods (clamp-on current transformers, voltage taps) with acoustic measurement technology. Acoustic sensors detect partial discharges and internal faults through sound waves generated by these phenomena, substituting electrical field measurements with acoustic field measurements to achieve superior detection capability without requiring direct electrical contact with the bushing
Solution Approach 2:
The patent introduces acoustic waves as an intermediary medium to detect internal faults and partial discharges. Instead of directly measuring electrical parameters, the system uses acoustic sensors to capture sound waves generated by fault conditions, translating invisible electrical phenomena into detectable acoustic signals for analysis
2Measurement precision
If acoustic sensors are placed directly on capacitor bushings, then measurement precision improves for detecting partial discharges, but device complexity and installation difficulty increase
Solution Approach 1:
The patent designs acoustic sensors with multi-functional capabilities that can detect not only partial discharges but also internal faults, overheating conditions, and other abnormal states. This universal detection capability consolidates multiple monitoring functions into a single sensor system, reducing the number of separate devices needed and simplifying installation while maintaining high measurement precision
Solution Approach 2:
The patent incorporates pre-configured signal processing algorithms and analysis methods into the acoustic sensor system before deployment. The sensors come with built-in capabilities for filtering, amplification, and initial analysis of acoustic signals, reducing the complexity of on-site configuration and installation while ensuring optimal detection performance from the outset
3Reliability
If multiple acoustic sensors are deployed for comprehensive monitoring, then reliability and detection accuracy improve, but device complexity and cost increase
Solution Approach 1:
The patent combines multiple acoustic sensors into an integrated monitoring system with centralized signal processing and analysis. The sensors work together as a coordinated network, sharing data and processing resources, which maintains high reliability through redundant detection capabilities while reducing overall system complexity compared to independent sensor systems
Solution Approach 2:
The patent implements feedback mechanisms where the monitoring system continuously analyzes acoustic signals and adjusts its operation based on detected conditions. The system provides real-time feedback on bushing health status, enabling predictive maintenance and reducing the need for complex manual monitoring while improving reliability through continuous adaptive observation
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
Ensures reliable and accurate monitoring of capacitor feedthroughs by minimizing the impact of environmental and operational variations, enabling early detection of damage and reducing the need for additional voltage measurements.
Implementation Method 1
the acoustic sensor is sensitive to acoustic waves generated by partial discharges and internal faults in the capacitor bushing
Data Source
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AI summary
The invention relates to a method for monitoring capacitor bushings (2a, 2b, 2c) for an alternating-current grid, wherein the alternating-current grid has a first, second, and third phase (A, B, C) and comprises: a first grid line (5a), with which the first phase and a first capacitor bushing (2a) are associated and on which a first grid voltage is present, a second grid line (5b), with which the second phase and a second capacitor bushing (2b) are associated and on which a second grid voltage is present, a third grid line (5c), with which the third phase and a third capacitor bushing (2c) are associated and on which a third grid voltage is present; each of said capacitor bushings comprises: a line (4), which is connected to the associated grid line, an electrically conductive covering (3), which surrounds said conductor; for each of said phases a corresponding characteristic value is determined for a characteristic variable characteristic of the capacitor bushing in question at a predefined initial time (t0); a corresponding standardized characteristic value is determined for the characteristic variable at a predefined later time (tn) after the initial time (t0) in accordance with the characteristic value in question and/or in accordance with at least one of the other characteristic values; it is checked whether the standardized characteristic value has changed impermissibly.