Partial Discharge Location in Electric Cables Using Trigger-Based Signal Processing
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Solution Overview
Problem
Existing methods for locating partial discharges in high-voltage cables face challenges in achieving high spatial resolution with large data volumes, requiring complex and time-consuming evaluation processes, and struggle with accurately determining the source of partial discharges, especially in long cables where attenuation and interference complicate the detection.
Innovation Solution
A method using a high-voltage source coupled with a decoupling unit and sensor unit, employing a trigger-based system to detect and classify partial discharge events by analyzing transit time differences and cable attenuation, reducing data volume through feature pairing and statistical evaluation to quickly determine the location of partial discharges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If trigger-based methods are used to limit data volume, then the amount of data is reduced, but the evaluation is carried out much later after the measurement with enormous time required for meaningful localization
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing travel time information for different cable sections before the actual measurement. During measurement, the trigger unit already has reference data ready, enabling immediate evaluation of partial discharge locations without time-consuming post-processing calculations.
Solution Approach 2:
The patent replaces manual evaluation by measurement technicians with an automated evaluation system. The trigger unit automatically processes sensor signals, compares them with stored reference data, and determines partial discharge locations without human intervention, dramatically reducing evaluation time.
2Measurement precision
If high bandwidths are available for high spatial resolution, then spatial resolution is improved, but large amounts of data are required for mostly digital processing
Solution Approach 1:
The patent extracts only the essential features from the sensor signals using the trigger unit. Instead of processing complete high-bandwidth signals, the system identifies and processes only relevant partial discharge events with their key characteristics, maintaining spatial resolution while minimizing data volume.
Solution Approach 2:
The patent segments the cable into different sections with stored reference travel times. This segmentation allows the system to process signals in discrete, manageable units corresponding to specific cable sections, reducing the overall data processing requirement while maintaining precise location identification.
3Measurement precision
If cable attenuation is considered for long cables, then detection accuracy is improved, but the partial discharge and reflection are greatly attenuated making locating more difficult
Solution Approach 1:
The patent applies preliminary action by pre-storing reference travel time data that accounts for cable attenuation characteristics. This reference data compensates for signal attenuation effects, allowing accurate partial discharge location even in long cables where attenuation would otherwise make detection difficult.
Solution Approach 2:
The patent uses feedback by comparing sensor signals with stored reference data that incorporates cable attenuation information. This comparison allows the system to compensate for attenuation effects and accurately determine partial discharge locations despite signal weakening in long cables.
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
Enables rapid and direct localization of partial discharges at the cable end, reducing evaluation time and improving accuracy by minimizing the impact of interference, thus facilitating timely maintenance and reducing cable downtime.
Implementation Method 1
a sensor unit (4) connected to the decoupling unit (3) and to the data processing system (5), wherein the data processing system (5) determines a partial discharge or partial discharges from sensor signals from the sensor unit (4)
Implementation Method 2
a decoupling unit (3) connected to one end (7) of the cable (2), wherein a sensor unit (4) is connected to the decoupling unit (3)
Data Source
Figure 1~2
Figure 3~4
AI summary
The invention relates to methods and devices for locating partial discharges in electric cables, comprising a high-voltage source which is coupled to the cable to be tested, an outcoupling unit which is connected to one end of the cable, and a data processing system which is connected to the outcoupling unit via a sensor unit and which ascertains a partial discharge or partial discharges from the sensor signals when present. The methods and devices are characterized in particular by a short analysis duration of the locating process. This is achieved by detecting events, parameterizing the events detected as pulses, pairing the parameterized events which are detected as pulses, classifying the event pairs, assigning a partial discharge on the basis of the classification, and determining the location of the partial discharge(s) from the delay between the respective partial discharge and the reflection corresponding to the partial discharge.