Partial Discharge Signal Evaluation in Multi-Phase Systems
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Solution Overview
Problem
Conventional methods for evaluating partial discharge signals in multiphase alternating current systems require separate measurement units for each line conductor, making it costly and impractical to monitor partial discharge activities online during regular operation.
Innovation Solution
A method that evaluates partial discharge signals by defining characteristic variables, assigning phase positions, and clustering signals in a multidimensional space, allowing for the identification of partial discharge activities for each line conductor using a single measurement unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If separate measurement units are used for each line conductor, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent merges multiple measurement functions into a single measurement unit by detecting partial discharge signals from multiple line conductors through one location and separating them using signal processing techniques. The superposition of partial discharge signals from different line conductors is resolved by evaluating characteristic variables and phase positions, allowing accurate identification of individual conductor activities without requiring separate measurement units for each conductor.
Solution Approach 2:
The measurement unit is designed with universal functionality to handle multiple line conductors simultaneously. By implementing characteristic variable evaluation and phase position assignment, a single measurement unit can process and differentiate partial discharge signals from multiple alternating currents with different phase shifts, making the system multi-functional rather than requiring dedicated units for each conductor.
2Measurement precision
If offline measurements are performed, then measurement precision is improved, but productivity decreases due to operational interruptions
Solution Approach 1:
The patent enables continuous online monitoring of partial discharge activities during regular operation of electric machines. The measurement unit operates continuously without interrupting the machine's function, allowing trends in partial discharge activities to be monitored over time and correlated with environmental influences such as temperature, air humidity, and atmospheric pressure, thereby maintaining both measurement accuracy and operational productivity.
3Device complexity
If partial discharge signals are detected at only one location, then device complexity is reduced, but measurement precision deteriorates due to signal overlay
Solution Approach 1:
The patent introduces characteristic variables and phase position information as intermediary parameters that mediate between the overlaid signals and the individual conductor activities. By assigning phase positions based on the alternating currents and evaluating characteristic variables of the superimposed signals, the system can distinguish and attribute signals to specific line conductors even when detected at a single location, effectively using these intermediaries to resolve the signal mixing problem.
Data Source
AI summary
A method for evaluating partial discharge signals. Partial discharge signals are captured, at only one point or at a plurality of points, near insulation of the electrical outer conductors of a multi-phase alternating current. The multi-phase alternating current, flowing in respective outer conductors, has fixed phase shifts relative to each other. Partial discharge signals are superposed on each other. At least one characteristic variable of the partial discharge signals is defined. Each partial discharge signal is assigned a phase position. A characteristic variable value of each characteristic variable is determined. Each partial discharge signal is assigned a number tuple from each characteristic variable value of the partial discharge signal and from the phase position. Clusters of the partial discharge signals in a multidimensional space with points formed by the number tuples are determined. A partial discharge activity is determined for each outer conductor from the determined clusters.