Influence of tertiary stabilizing windings on zero-sequence performance of three-phase three-legged YNynd transformers. Part I: Equivalent circuit models Articles uri icon

publication date

  • March 2017

start page

  • 32

end page

  • 40

volume

  • 144

International Standard Serial Number (ISSN)

  • 0378-7796

Electronic International Standard Serial Number (EISSN)

  • 1873-2046

abstract

  • Ti(C,N)-based cermets are currently used in high speed cutting tools industry due to its high thermal stability. In previous works, Fe was proposed as metal matrix, however the use of iron as continuous matrix strongly affects the processing due to the low wetting capability of molten Fe with the reinforcement phase, Ti(C,N). To solve this problem, the use of alloys such as FeNi has been proposed, where Ni improves the wettability between the ceramic and the metal phases. This work proposes a bottom-up approach to build the cermet microstructure through the synthesis of metal nanoparticles (NPs) on the surface of Ti(C,N) micrometric particles, creating Ti(C,N)-Ni core-shell structures. For that purpose, the in-situ synthesis of Ni NPs through the chemical reduction of a Ni precursor onto the surface of micrometric Ti(C,N) particles, previously stabilized in an aqueous suspension, was proposed. Core-shell structures were characterized by X-Ray Diffraction (XRD), scanning electron microscopy (SEM), field emission scanning electron microscopy (FE-SEM), scanning transmission electron microscopy (STEM), high resolution scanning electron microscopy (HRTEM), energy-dispersive X-Ray spectroscopy (EDX) and Raman Spectroscopy. (C) 2016 Elsevier Ltd. All rights reserved.

keywords

  • three-winding transformers; tertiary stabilizing windings; transformer zero-sequence performance; onsite zero-sequence impedance measurements; transformer equivalent circuits; parameters; impedance