VHF UHF Detector Grid for Partial Discharge Location
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Solution Overview
Problem
Existing methods for locating partial discharge emission zones in power transformers are hindered by sensitivity to non-discharge disturbances, high costs, and the need for continuous discharge activity, particularly when using ultrasonic detectors and ultra-violet cameras.
Innovation Solution
A method utilizing four calibrated high-frequency (VHF) or ultra-high frequency (UHF) detectors positioned in a grid to calculate time differences and locate discharge zones through intersection equations, with an optional extension to a third plane for volumetric detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If ultrasonic detectors are used to locate partial discharge sources, then the detection capability is improved, but the sensitivity to non-discharge disturbances increases and the location time becomes very long on large sites
Solution Approach 1:
The patent changes the detection parameter from ultrasonic frequency to VHF/UHF electromagnetic frequency range. This parameter change allows selective detection of electromagnetic signals emitted by partial discharges while being insensitive to acoustic disturbances, thus resolving the contradiction between detection capability and sensitivity to non-discharge disturbances
Solution Approach 2:
The patent replaces the mechanical ultrasonic detection system with an electromagnetic field-based detection system using VHF/UHF detectors. This substitution eliminates sensitivity to acoustic disturbances while maintaining discharge detection capability through electromagnetic signal detection
2Measurement precision
If ultrasonic detectors are used to locate partial discharge sources on large sites, then the detection capability is improved, but the location time becomes very long
Solution Approach 1:
The patent introduces a fourth dimension (time) by measuring the arrival time of electromagnetic signals at multiple detectors. By calculating time differences of arrival (TDOA) and using hyperbolic intersection methods, the system rapidly determines the spatial coordinates of discharge sources, reducing location time from hours to seconds even on large sites
Solution Approach 2:
The patent uses multiple identical VHF/UHF detectors positioned at different locations to simultaneously detect and record discharge signals. This parallel detection approach allows rapid comparison of signal arrival times and immediate calculation of discharge source positions, significantly reducing location time compared to sequential ultrasonic scanning
3Measurement precision
If ultra-violet cameras are used to locate partial discharge sources, then the detection capability for corona discharges is improved, but the cost becomes very high
Solution Approach 1:
The patent employs relatively inexpensive VHF/UHF detectors and standard electronic signal processing equipment instead of costly ultra-violet cameras. The system achieves comparable or superior detection capability for corona discharges using affordable electromagnetic detection technology, significantly reducing the overall system cost
Solution Approach 2:
The patent changes the detection parameter from ultraviolet optical frequency to VHF/UHF electromagnetic frequency. This parameter change enables detection of corona discharges using cheaper electronic detectors rather than expensive ultraviolet-sensitive cameras, maintaining detection precision while reducing cost
4Measurement precision
If ultrasonic detectors or ultra-violet cameras are used, then discharge detection is possible, but the discharge activity must be continuous and not sporadic
Solution Approach 1:
The patent implements continuous monitoring of electromagnetic signals in the VHF/UHF range, maintaining constant detection readiness. This continuous monitoring approach captures sporadic discharges as they occur without requiring the discharge activity to be continuous, thereby improving adaptability to intermittent discharge patterns
Solution Approach 2:
The patent uses periodic sampling of electromagnetic signals at high rates to detect sporadic discharges. By continuously sampling the electromagnetic environment and analyzing signal arrivals in real-time, the system can detect intermittent discharges that occur periodically or randomly, enhancing versatility for various discharge patterns
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 effectively locates partial discharge sources with reduced interference and cost, enabling rapid identification even in large areas, and can determine discharge zones in both planar and volumetric forms.
Implementation Method 1
a step of measuring partial discharge signals by means of the four measurement channels, the four VHF and/or UHF detectors being positioned in an (X, Y) plane
Implementation Method 2
a step of calculating a time difference TOAD2−TOAD3, corrected using the calibration data resulting from the calibration step, between the reception times of the signals measured by the measurement channels including the detectors D2 and D3, respectively
Data Source
AI summary
A method of locating a partial discharge emission zone and to the associated device. The method is characterized in that it comprises a step of measuring partial discharge signals by means of four identical measurement channels each including a VHF and/or UHF detector, the four VHF and/or UHF detectors being positioned at the four vertices of a square or rectangle in such a manner that the partial discharge emission zone is determined inside the square or rectangle.