Partial Discharge Determination for Underground Power Cables
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Solution Overview
Problem
Existing methods for determining insulation deterioration in underground power transmission cables require the creation of multiple standard patterns, which is time-consuming and can lead to incorrect diagnoses if patterns with high similarity are not present in the standard set.
Innovation Solution
A method that uses a partial discharge determination system to classify partial discharge patterns without relying on pre-prepared standard patterns, employing a distribution pattern generation unit, classification units, and an evaluation unit to determine the degree of insulation deterioration based on standardized charge amount and phase angle distributions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple standard patterns are created for partial discharge diagnosis, then diagnostic coverage is improved, but time consumption and complexity increase
Solution Approach 1:
The system automatically generates standard patterns by measuring partial discharge characteristics at different insulation deterioration stages without requiring manual preparation. The determination device itself performs the pattern generation task, eliminating the time-consuming manual pattern creation process while ensuring comprehensive diagnostic coverage.
Solution Approach 2:
The system pre-measures and stores standard patterns corresponding to various insulation deterioration stages before actual diagnosis. By conducting measurements in advance at different deterioration stages (from healthy to severely degraded insulation), the system prepares a library of reference patterns that can be quickly compared against during operational diagnosis, reducing real-time diagnostic time.
2Productivity
If standard patterns are pre-prepared for comparison, then diagnosis speed is improved, but diagnostic accuracy decreases when patterns with high similarity are not present
Solution Approach 1:
The system dynamically adapts the standard patterns based on the specific characteristics of the measured partial discharge signals. Rather than relying on fixed, pre-defined patterns, the determination device adjusts and refines the comparison process to match the actual insulation condition, ensuring accurate diagnosis even for unique or atypical deterioration patterns that may not exactly match pre-prepared standards.
Solution Approach 2:
The system varies and optimizes comparison parameters during the diagnosis process to improve matching accuracy. By adjusting parameters such as phase angle ranges, charge amount thresholds, and pattern weighting factors based on the specific measurement context, the system achieves both fast comparison and high diagnostic accuracy, resolving the trade-off between speed and precision.
3Reliability
If pattern matching is performed with multiple standard patterns, then comprehensive diagnosis is achieved, but device complexity increases
Solution Approach 1:
The determination device divides the partial discharge analysis into distinct segments: phase angle analysis, charge amount analysis, and pattern matching. Each segment processes specific characteristics independently and contributes to the overall diagnosis. This segmentation allows comprehensive analysis without requiring a monolithic complex system, as each module can be optimized and implemented separately.
Data Source
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AI summary
An object of the present invention is to propose a partial discharge determination device and method that can reliably determine the amount of partial discharge occurring in an underground power transmission cable. A distribution pattern of a set of the charge amount and the occurrence phase angle of each partial discharge occurring in a period of one or more cycles of an applied voltage of a power transmission cable is sequentially generated, a first classification process in which the distribution pattern is classified into any one of classes on the basis of a standard distribution pattern for each class, each class representing a state of degradation of the underground power transmission cable based on the amount of partial discharge, and a second classification process in which the distribution pattern is classified by clustering, a classification result by the first classification process is evaluated on the basis of a classification result by the second classification process, and the amount of partial discharge is determined based on the evaluation result.