Comparison of methods for detecting the signal arrival time in TDOA localization method

This article presents a part of radiofrequency method, known as ultra-high frequency (UHF) method for detection and localization of partial discharges in high-voltage transformers. The UHF method is the most advancing method for this type of transformer diagnostic. The state of the art in instrument technology allows real-time acquisition and processing of pulsed broad band signals together with 3D localization of PD occurrence. The UHF method is based on measurements of electromagnetic waves in UHF spectrum produced by PD. Typical spectrum of the PD UHF signal ranges from hundreds of MHz to units of GHz. Spatial localization of the signal origin is based on Time Difference of Arrival (TDOA) algorithm. Accuracy of the TDOA is determined by accuracy of detecting of the signal arrival time on each measured channel. Verification of the detection algorithms function is done on real measured data from 500 MVA high-voltage transformer.