Determination of Transformer Winding Radial Deformation Using UWB System and Hyperboloid Method

Abstract

On-line monitoring of the transformer winding using electromagnetic waves has recently been proposed for the detection of mechanical defects of transformer winding. In this paper, a new method, which uses the UWB radar measurement results and is based on locus of objects in the space, is proposed for the three-dimensional positioning of transformer winding radial deformation location. The proposed experimental set-up for this method named "Hyperboloid method" is modeled using CST (Computer Simulation Technology) software. In this paper, Vivaldi antennas suitable for measurements in environments with multi-path, are used and the analysis is performed in the time domain. The simulation results show that the exact threedimensional location of the radial deformation can be detected with a good accuracy.

Determination of transformer HV winding axial displacement extent using hyperbolic method – a feasibility study

“…where c is the light speed equal to 3 × 10 8 m/s. The transformer oil will affect the velocity of electromagnetic wave, considering its effect by the equation c = 3 × 10 8 / ε r m/s, where ε r is the relative dielectric constant of the oil [21].…”

“…4 illustrates a side view of the simulated system. Due to their numerous advantages, especially for UWB systems, Vivaldi antennas are used in this paper to send and receive signals [16,21,29]. The parameters of the simulated winding are given in Table 2.…”

“…Among mechanical fault diagnosis methods, those that are capable of providing online information about the winding status without taking the transformer out of service, are of great importance. In recent years, a novel method capable of online monitoring has been proposed by employing electromagnetic waves [19][20][21]. In this method, electromagnetic waves are emitted to the transformer winding using an antenna, and the reflections are then recorded by the receiving antennas.…”

“…Hence, training all defected models is hardly practical; these methods may not be employed to in the case of actual transformer winding. In [20,21,24], UWB signals have been used to investigate the mechanical defects in power transformer high-voltage (HV) winding. In [21,24], synthetic aperture radar (SAR) image processing method and hyperbolic method based on time difference of arrival (TDOA) have been used, respectively, to investigate the RD defect while AD has not been discussed in those researches.…”

“…In [20,21,24], UWB signals have been used to investigate the mechanical defects in power transformer high-voltage (HV) winding. In [21,24], synthetic aperture radar (SAR) image processing method and hyperbolic method based on time difference of arrival (TDOA) have been used, respectively, to investigate the RD defect while AD has not been discussed in those researches. The major drawback of SAR imaging used for AD detection [25] is that it needs to move the antennas alongside transformer winding, which is not practical in the current structure of transformer tank.…”