Acoustic Based Localization of Partial Discharge Inside Oil-Filled Transformers

Abstract

This paper addresses the localization of Partial Discharge through a 3D Finite Element Method analysis of acoustic wave propagation inside a 3-phase 35kV transformer with the help of COMSOL Multiphysics software. Due to the complexity inside transformers, acoustic waves generated by PDs cannot simply be detected with typical acoustic sensors, especially when PDs happen inside inner windings. These waves are distorted and attenuated along with their propagation. The type, number, and position of sensors are essential factors in PD localization inside a transformer. A new installation arrangement of fiber-optic acoustic sensors inside the transformers is proposed with this information. This array of acoustic sensors has significant effects on PD localization accuracy and has immunity from on-site noise and interference; more importantly, they can be installed after transformer manufacturing. They are reachable if needed to be repaired or replaced. Several numerical studies have been carried out considering different PD source positions, and the Levenberge-Marquardt algorithm is employed for solving localization equations.

Quantitative analysis and evaluation of the optimization method of transformer partial discharge ultrasonic sensor monitoring

“…In order to achieve all-round detection of transformer PD faults, reduce the leakage rate and improve detection efficiency, all possible locations of PD need to be fully considered in the simulation process. According to previous scholars [15][16][17][18][19][20][21], PD in transformers mostly occurs in internal air gaps, surface defects in solid insulation materials, and air bubbles in the oil. Therefore, all possible locations of PD are fully considered and categorized into the following two scenarios.…”

“…Meitei et al [17] used COMSOL to build a two-dimensional planar model of a three-phase transformer and obtained the law that the sound pressure gradient is larger in the area with faster sound velocity inside the transformer through simulation. Based on this, Hamidreza et al [18] used COMSOL to construct a three-dimensional model of a three-phase transformer and found through simulation that the ultrasonic signals fold reflection and attenuation are more serious when the PD source is inside the winding. Qi et al [19] studied the spatial and temporal distribution of transformer PD acoustic pressure and obtained that the longer the ultrasonic signals propagation path in the transformer, the more serious the signal amplitude attenuation.…”

Evaluation of a calibration technique in measuring partial discharges inside mineral oils with a high‐frequency current transformer (HFCT) sensor: A case study

“…The conventional methods, defined in the IEC 60270, use the concept of apparent charge [1]. There are different methods of unconventional PD measurements that rely on high-frequency current transformer (HFCT) sensors, Rogowski coils, magnetic sensors, and acoustic sensors [2][3][4][5][6][7][8][9][10][11][12]. Sikorski et al [2] presented a prototype, hybrid on-line PD monitoring system.…”

“…Romano et al [8] presented and analyzed an innovative PD measurement instrument based on an antenna sensor. In [10] and [11], the authors worked on the measurement and localization of PDs inside the oil-filled transformer with acoustic emission and fibre-optic sensors using both simulation and experimental studies.…”

“…These unconventional methods [2][3][4][5][6][7][8][9][10][11][12] have some advantages over the conventional method described in [1]. Because of more immunity to on-site noise and interferences, sensitive PD measurement can be done even with AC sources, or indeed in online testing when the test object is connected to the grid.…”