Ester-based dielectric fluids have gained widespread popularity for applications in high voltage apparatus. Synthetic and natural esters have been subjected to research for decades vis-à-vis mineral insulating oils around the world. Although many researchers favor the application of ester fluids, utilities are still uncertain and application of these alternatives remains a challenge. The intent of this survey is to present recent research progress and highlight the state of the art of key aspects that should be emphasized in future research. The contemporary research scenarios pertaining to the performance of ester fluids versus mineral oils, miscibility, and retrofilling of insulating fluids are discussed. In addition, pre-breakdown phenomena, usage of esters in on-load tap changers, environmental and fire resistance properties, and use of esters in cold climates are also discussed. Importantly, challenges and future aspects that should be investigated to improve the existing knowledge of ester dielectric fluids for applications in transformer technology are highlighted.

This work reports the synthesis of novel quaternary transparent conducting oxide Cd(1-x)Sn(1-x)InxGaxO3( x=0.1, 0.2, 0.3) at 1225°C via solid state reaction route. The investigations on structural, optical and electrical properties have been carried out. Powder X-ray diffraction revealed the phase purity and distorted orthorhombic structure of the species synthesized. Distortion of the structure is due to the substitution of In3+and Ga3+in CdSnO3 (JCPDS card no.340885) matrix. The optical transmittance approximated by the reflectance shows considerable increase in the transmittance of visible light along with the increase of substitution. Typical Burstein-Moss effect is observed with the increase in x value as a variation in optical bandgap from 2.7 to 2.9eV. Four point Hall measurements by Van der-Pauw method exhibit superior properties in charge carrier concentration and mobility. Maximum bulk charge concentration of 4.78x1017 cm-3is obtained for x=0.3. Hall mobility depends on carrier concentration and steeply increases with the carrier concentration. Considerable drop in the resistivity of the material along with higher transmittance is a critical finding in the experiment.

No abstract

No abstract

No abstract