In this paper, the design and application of a circular microstrip antenna for partial discharge detection is presented. For this purpose, the truncated ground plane technique was applied for the bandwidth enhancement. In addition, aiming at an optimized structure, the computational simulations with several combinations of the antenna dimensional parameters were performed. In order to verify whether the developed antenna met the prerequisites (bandwidth and gain) for practical application in partial discharge detection, the optimized antenna was subjected to tests in an anechoic chamber. Finally, the antenna sensitivity was compared with the IEC 60270 standard method. For this purpose, the simultaneous tests were carried out in a partial discharge generator arrangement composed of an oil cell with point-to-plane and plane-to-plane electrode configurations. The developed antenna can detect apparent charge values higher than 30 pC and has an average gain greater than 2 dB along its bandwidth. The obtained results attested to the potential of the developed antenna for the development of UHF sensors for partial discharge detection in high-voltage equipment.

A new, bio-inspired printed monopole antenna (PMA) model is applied to monitor partial discharge (PD) activity in high voltage insulating systems. An optimized sensor was obtained by designing a PMA in accordance with the characteristics of the electromagnetic signal produced by PD. An ultra-wideband (UWB) antenna was obtained by applying the truncated ground plane technique. The patch geometry was bio-inspired by that of the Inga Marginata leaf, resulting in a significant reduction in size. To verify the operating frequency and gain of the PMA, measurements were carried out in an anechoic chamber. The results show that the antenna operating bandwidth covers most of the frequency range of PD occurrence. Moreover, the antenna presented a good sensitivity (mean gain of 3.63 dBi). The antenna performance was evaluated through comparative results with the standard IEC 60270 method. For this purpose, simultaneous tests were carried out in a PD generator arrangement, composed by an oil cell with point-to-plane electrode configurations. The developed PMA can be classified as an optimized sensor for PD detection and suitable for substation application, since it is able to measure PD radiated signals with half the voltage levels obtained from the IEC method and is immune to corona discharges.

In this paper, the design and development of a bio-inspired UHF sensor for partial discharge detection in power transformers is presented. The UHF sensor was developed for external use in dielectric windows of power transformers. For this purpose, a microstrip antenna was designed with a radiating element shape based on the leaf of the Jatropha mollissima (Pohl) Baill plant. Then, an epoxy coating and an aluminium enclosure were developed to protect the antenna against corrosion and to provide mechanical support, external noise immunity, and a lifetime compatibility with power transformers. In order to verify the electrical parameters of the developed sensor, measurements of the gain and the reflection coefficient were performed in an anechoic chamber. Lastly, the antenna sensitivity for denominated partial discharge (PD) detection was compared with the IEC 60270 standard method. For this purpose, simultaneous tests were carried out in a partial discharge generator setup, composed of an oil cell with needle-plane electrodes. The experimental tests demonstrated the effectiveness of the sensor for detecting PD signals with apparent charge values higher than 35 pC.

In this article, it is provided a comprehensive survey on the most relevant research in the area of detection, classification and location of partial discharge (PD) sources using the radiometric or ultra high frequency (UHF) method, focusing mainly on the works related to the use of antennas. To the best of the authors knowledge, this is the first review paper that focuses on the application of antennas based on UHF method in the complete diagnosis of PD. Specifically, it is first presented the main contributions to the development and optimization of UHF sensors for application in the detection of PD sources. Second, articles that used the UHF method to identify different types of PD in high voltage equipment are described. Finally, the main contributions regarding the location of sources of defects using the radiometric method are presented. Summary of works in the area of UHF detection sensors, PD classification and PD location, with their respective contributions, are shown. Finally, research trends, challenging and open issues are discussed. The purpose of this article is to provide important information about the complete diagnosis of PD, which could be used to guide the development of more efficient techniques in this research area.

This paper discusses the application of the first peak and cumulative energy methods to calculate the time difference of arrival (TDOA) of UHF signals emitted by a partial discharge source in order to locate it. We used a 200 × 200 × 97 cm3 dimensional arrangement composed of four UHF printed monopole antennas, which was bio-inspired by the Jatropha mollissima (Pohl) Baill leaf. In addition, an oil cell composed of a pair of immersed flat-tip electrodes was used as a source of partial discharge (PD). The oil cell was positioned at four different coordinates in order to determine the efficiency of source localization based on the signals detected by the antennas and the applied methods. Finally, we evaluated the effects of the addition of noise filtering techniques and the sampling error of the measuring instrument on the localization results. Both TDOA extraction methods converged to satisfactory location results considering the dimensional arrangement evaluated, resulting in absolute errors of 7.20 cm up to 9.00 cm and 5.40 cm up to 10.96 cm, regarding the real PD position, for the cumulative energy and first peak methods, respectively.

This paper presents an algorithm for the localisation of partial discharge (PD) sources in power transformers based on the electromagnetic waves radiated by a PD pulse. The proposed algorithm is more accurate than existing methods, since it considers the effects of the reflection, refractions and diffractions undergone by the ultra-high frequency (UHF) signal within the equipment tank. The proposed method uses computational simulations of the electromagnetic waves generated by PD, and obtains the time delay of the signal between each point in the 3D space and the UHF sensors. The calculated signals can be compared with the signals measured in the field, so that the position of the PD source can be located based on the best correlation between the simulated propagation delay and the measured data. The equations used in the proposed method are defined as a 3D optimisation problem, so that the binary particle swarm optimisation algorithm can be used. To test and demonstrate the proposed algorithm, computational simulations were performed. The solutions were sufficient to identify not only the occurrence of defects, but also the winding and the region (top, centre or base) in which the defect occurred. In all cases, an accuracy of greater than 15 cm was obtained for the location, in a 180 MVA three-phase transformer.