An experimental validation of partial discharge localization using electromagnetic time reversal.

Area of Science:

• Electrical Engineering
• Non-destructive Testing
• Signal Processing

Background:

• Accurate localization of partial discharge (PD) sources is crucial for power transformer maintenance and reliability.
• Traditional methods like Time Difference of Arrival (TDoA) require multiple sensors and synchronized timing, posing practical challenges.
• Time Reversal (TR) has emerged as a promising alternative for PD source localization due to its potential for single-sensor application.

Purpose of the Study:

• To experimentally demonstrate the efficacy of the Time Reversal (TR) process for locating partial discharge (PD) sources in power transformers.
• To validate TR's capability to function with a single sensor, eliminating the need for complex sensor arrays and synchronization.
• To assess the impact of internal structures, such as transformer windings, on the localization accuracy of the TR method.

Main Methods:

• A laboratory setup was developed to experimentally implement the core steps of the TR process: signal recording and time-reversed back-injection.
• Both frequency and time domain approaches were employed for signal processing during the TR procedure.
• The peak electric field value at the reconstructed focus was utilized as the criterion for identifying the PD source location.

Main Results:

• The experimental demonstration successfully validated the TR process for PD source localization.
• The proposed TR method achieved a localization accuracy better than 2.5 cm within a realistic transformer tank model.
• The presence of scatterers, including transformer windings, did not significantly degrade the localization accuracy of the TR technique.

Conclusions:

• Time Reversal (TR) is a viable and accurate technique for locating partial discharge (PD) sources in power transformers, even with a single sensor.
• The experimental validation confirms TR's advantages over TDoA, including reduced sensor requirements and no need for line-of-sight or time synchronization.
• The robustness of the TR method against internal scattering elements makes it a practical solution for real-world transformer monitoring.