title: On the Use of Monopole Antennas for Determining the Effect of the Enclosure of a Power Transformer Tank in Partial Discharges Electromagnetic Propagation.
abstract: A well-defined condition-monitoring for power transformers is key to implementing a correct condition-based maintenance (CBM). In this regard, partial discharges (PD) measurement and its analysis allows to carry out on-line maintenance following the standards IEC-60270 and IEC-60076. However, new PD measurements techniques, such as acoustics or electromagnetic (EM) acquisitions using ultra-high-frequency (UHF) sensors are being taken into account, IEC-62478. PD measurements with antennas and the effect of their EM propagation in power transformer tanks is an open research topic that is considered in this paper. In this sense, an empty tank model is studied as a rectangular cavity and their resonances are calculated and compared with their measurement with a network analyser. Besides, two low cost improved monopole antennas deployed inside and outside of the tank model capture background noise and PD pulses in three different test objects (Nomex, twisted pair and insulator). The average spectrum of them are compared and can be found that mainly, the antenna frequency response, the frequency content distribution depending on the PD source and the enclosure resonances modes are the main factors to be considered in PD acquisitions with these sensors. Finally, with this set-up, it is possible to measure PD activity inside the tank from outside.
authors.affiliation: Generation and Distribution Network Area. Department of Electrical Engineering. Leader in Innovation, Technology and R&amp;D, Boslan Engineering and Consulting S.A., Madrid 28034, Spain. rasbarracin@gmail.com.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Albarracín
authors.affiliation: Department of Electrical Engineering, Universidad Técnica Federico Santa María, Santiago de Chile 8940000, Chile. jorge.ardila@usm.cl.
authors.forename: Jorge Alfredo
authors.initials: JA
authors.lastname: Ardila-Rey
authors.affiliation: Department of Electrical and Electronic Engineering Technology, Jubail Industrial College, Road No. 6, 8244 Al Huwailat, Al Jubail 35718, Saudi Arabia. abdullahi.masud@gmail.com.
authors.forename: Abdullahi Abubakar
authors.initials: AA
authors.lastname: Mas'ud
keywords: VHF and UHF sensors; condition monitoring; monopole antennas; partial discharges; power transformer tank
references.citation: Sensors (Basel). 2015 Apr 27;15(5):9882-98
references.pmid: 25923935
references.citation: ISA Trans. 2015 Sep;58:389-97
references.pmid: 25997372