Phase-Locked Partial Discharge Source Identification Under RF Interference
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Solution Overview
Problem
Existing methods for detecting partial discharge in medium and high voltage equipment are expensive and fail to reliably distinguish partial discharge emissions from interfering radio transmissions in a crowded frequency spectrum, necessitating improved continuous, on-line monitoring systems.
Innovation Solution
A method and apparatus using ultra-high frequency radio wave detection with phase-locked timing and cyclical timers to identify partial discharge sources, employing narrow band detectors and temporal coincidence of signals to filter out interference, and classify partial discharge based on signal patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If ultra-high frequency radio wave detection is used to detect partial discharge, then sensitivity and detection capability are improved, but the ability to distinguish from interfering radio transmissions deteriorates due to crowded frequency spectrum
Solution Approach 1:
The patent segments the detection process into multiple independent analysis dimensions: temporal segmentation through cyclical timing windows synchronized to power frequency, frequency segmentation through spectral analysis, and pattern segmentation through recognition of characteristic discharge signatures. This multi-dimensional segmentation enables the system to isolate true partial discharge signals from interfering radio transmissions by requiring coincidence across multiple segments.
Solution Approach 2:
The patent introduces several intermediary mechanisms: a cyclical timer synchronized to the power frequency acts as an intermediary to gate and organize detection windows; spectral analysis serves as an intermediary to transform time-domain signals into frequency-domain characteristics; and pattern recognition algorithms act as intermediaries to compare detected signals against known partial discharge signatures. These intermediaries enable reliable discrimination without reducing detection sensitivity.
2Reliability
If continuous on-line monitoring is implemented, then preventive maintenance capability is improved, but cost and system complexity increase
Solution Approach 1:
The patent designs the monitoring system to perform multiple functions through a unified architecture: the same UHF detection apparatus and signal processing system simultaneously detect partial discharge, characterize discharge types through pattern recognition, locate discharge sources through timing analysis, and provide continuous monitoring data. This multi-functionality reduces overall system complexity compared to implementing separate systems for each function.
Solution Approach 2:
The system employs self-service mechanisms through automated pattern recognition and classification algorithms that automatically identify and categorize partial discharge types without human intervention. The cyclical timing and synchronization mechanisms automatically adapt to power frequency variations, and the system self-calibrates by comparing detected patterns against stored reference signatures, reducing operational complexity.
3Reliability
If frequency selectivity is increased to avoid interfering transmissions, then signal discrimination is improved, but detection bandwidth and sensitivity are reduced
Solution Approach 1:
The patent transitions from one-dimensional frequency-domain filtering to multi-dimensional signal analysis by incorporating temporal dimension (cyclical timing windows synchronized to power frequency), amplitude dimension (signal strength thresholds), and pattern dimension (spectral and temporal signature matching). This dimensional expansion enables the system to maintain broad frequency bandwidth while achieving superior interference rejection through requiring signal coherence across multiple dimensions simultaneously.
Solution Approach 2:
The patent employs periodic action through cyclical detection windows synchronized to the power frequency cycle. The system opens detection gates at specific phases of the power cycle where partial discharge is most likely to occur, creating periodic observation intervals. This periodic gating maintains high overall detection sensitivity while providing frequency selectivity by concentrating detection resources in time windows where target signals are expected rather than continuously monitoring all frequencies.
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
Enhances the reliability and sensitivity of partial discharge detection by filtering out interfering signals, allowing for precise localization of discharge sources in AC power systems, thereby improving maintenance efficiency and reducing false positives.
Implementation Method 1
the electromagnetic waves radiated from the point of discharge as an indicator of partial discharge
Data Source
AI summary
Method and system for identifying sources of partial discharge (PD), from a set of potential sources, in an alternating current three-phase high-voltage power-distribution system are disclosed. A timing signal is generated, phase-locked to a selected phase of three phases of the power-distribution system, having a measurable phase displacement from the selected phase. A cyclical timer is generated for indicating time within a power cycle based on a master clock phase-locked to the timing signal. A power-cycle period is partitioned into a number of dual observation windows, each dual observation window corresponding to a potential source and having two individual windows, π-radians apart, and a specified window width. From a PD-detection apparatus, using the timing signal and the timer, magnitudes and time instants of PD detection during successive power cycles are received. PD detection is associated with respective dual observation windows, hence respective PD sources based, on the time instants.