Transient phenomena in power transformers theoretical and practical approach
In recent decades the theoretical and experimental study of transient phenomena regarding power transformers has experienced a great development. Results of these studies allowed the elucidation of the main theoretical and practical aspects of the transient phenomena due to propagation of impulse voltages inside the transformers. These studies increased the safe operation of power transformer and led to the introduction of rational insulation usage and also helped to develop efficient protection measures.
Calculation methods for lightning impulse voltage distribution in power transformers
This paper aims to develop and update the methodology for calculating the stress to which the internal insulation of power transformer is subjected during lightning impulse test. Power transformer internal isolation consists of insolating intervals of oil impregnated paper, transformer board and oil. In whole, the transformer's insulation must withstand the voltage testing levels prescribed by the standards. One of the methods for determining the internal stress of various parts of the power transformer's insulation is by using mathematical models.
Comparative study of the molecular species of chloropropanediol diesters and triacylglycerols in milk fat
In an effort to establish the origin of the fatty acid esters of 3-chloropropanediol, which recently have been isolated in small amounts from goat milk, we compared the molecular species composition of the chlorohydrin diesters and of goat milk triacylglycerols. The chloropropanediol diesters were found to be composed of molecular species containing C10−C18 fatty acids and corresponded closely in carbon number to those calculated for the long chain sn-1,2-diacyl-glycerol moieties of goat milk triacylglycerols. The molecular species of goat milk total triacylglycerols contained C4−C18 fatty acids. It is suggested that triacylglycerols and chloropropanediol diesters are derived from the same pool of long chain fatty acids. A molecular distillate of bovine milk fat did not contain chloropropanediol diesters, while the available samples of human milk fat were shown to contain alkyldiacylglycerols as the major components of a neutral lipid fraction corresponding in polarity to the chloropropanediol diesters.