Partial Discharge Location Using Attenuation Parameters
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Solution Overview
Problem
Existing methods for locating partial discharges in elongate electric apparatuses with elongate geometry face challenges in accurately identifying and isolating homologous pulses, leading to unreliable and imprecise detection due to signal attenuation and interference from background noise, especially in long cables.
Innovation Solution
A device and method that utilize directional sensors and a processing unit to derive attenuation parameters from selected pairs of homologous pulses, allowing for precise calculation of the discharge site's distance from detecting stations, while employing synchronization and statistical processing to reliably identify and separate signals related to the same partial discharge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple sensors are coupled to the cable at different positions to detect partial discharges, then the accuracy of locating discharge sites is improved, but the complexity of the device increases and signal attenuation becomes more significant for long cables
Solution Approach 1:
The cable is divided into multiple detection zones by placing sensors at different positions along its length. Each sensor independently monitors its local segment, enabling precise localization of partial discharge sources while managing system complexity through modular segmentation of the detection process.
Solution Approach 2:
The patent transitions from single-point detection to multi-dimensional spatial detection by distributing sensors along the cable's length. This dimensional expansion from one to multiple detection points enables triangulation and time-difference-based localization, significantly improving measurement precision without proportionally increasing overall system complexity.
2Length of stationary object
If sensors are spaced far apart along the cable to cover longer distances, then the detection range is improved, but the ability to accurately identify homologous pulses deteriorates due to signal attenuation
Solution Approach 1:
The system employs feedback mechanisms where detected signals from multiple sensors are continuously compared and correlated. By analyzing the consistency of signal characteristics (amplitude, waveform shape, frequency content) across sensors and using feedback loops to adjust detection thresholds, the system maintains reliable identification of homologous pulses even over extended cable lengths where attenuation occurs.
Solution Approach 2:
The patent utilizes parameter changes in the detected signals, specifically the time difference of arrival and amplitude ratios between sensors. By monitoring how these parameters change with distance and comparing them against expected patterns, the system can reliably identify homologous pulses and distinguish them from noise or unrelated discharges, maintaining detection reliability across varying cable lengths.
3Duration of action of moving object
If the acquisition time window is extended to capture pulses traveling through multiple sensors, then the completeness of signal capture is improved, but the difficulty of identifying homologous pulses increases due to background noise
Solution Approach 1:
The system performs preliminary correlation analysis and pattern recognition on incoming signals before final identification. By pre-processing the acquired waveforms to extract characteristic features and compare them against known discharge patterns, the system prepares the data in advance, making the subsequent identification of homologous pulses more straightforward even within extended acquisition windows.
Solution Approach 2:
The patent employs periodic sampling and analysis of signal characteristics across the acquisition window. By dividing the extended time window into periodic segments and analyzing signal patterns at regular intervals, the system can identify recurring homologous pulse patterns while filtering out random background noise, thus reducing the difficulty of identification despite the longer observation period.
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
The solution provides a robust and accurate method for locating partial discharges, reducing errors associated with signal interference and attenuation, and enhancing the reliability of identifying homologous pulses, thereby improving the precision and reliability of discharge site location.
Implementation Method 1
a first and a second sensor connected to the apparatus in a first and a second detecting station and spaced out along the apparatus, for detecting electric signals
Implementation Method 2
measuring the time interval that elapses between one signal and the signal reflected back by that signal from the opposite end of the cable. The distance of the source of that signal from the detection point is then calculated on the basis of the speed at which the signals propagate in that cable
Data Source
AI summary
A method for locating partial discharges occurring at a discharge site (2) in an electric apparatus (3) with elongate geometry and generating corresponding electric pulses (4) propagating in opposite directions along the apparatus (3) from the discharge site (2) comprises the steps of detecting (11) the electric pulses (4) picked up by a first and a second sensor (5, 7), operatively connected to the apparatus (3) and spaced out along it, and generating corresponding electric signals representative of the waveform of the pulses (4), selecting (12) at least one pair of signals, detected in the consecutive sensors (5, 7), and representative of a pair of homologous pulses (4), relating to the same partial discharge and propagating in opposite directions along the apparatus, deriving, for the signals of the selected pair of homologous pulses (4), at least one attenuation parameter, correlated with a quantity that is variable depending on the distance travelled by the pulses (4), calculating (13) the distance between the discharge site (2) and the sensors, based on processing the values of the attenuation parameter for the signals of the selected pair of homologous pulses (4).