Introduction
Principle
of operation; Vector Group; Two winding and Three winding Transformer;
Rectifier Transformer; Parallel
operation and Load Sharing.
Protection
Over
load, Over current; Differential; Restricted Earth fault; Buchholz.
Maintenance
Test
Routine
maintenance testing; IR, PI, Dielectric absorption, High- Pot; tan
d,
DC
winding resistance, TTR (Transformer turns ratio), Magnetic Balance;
Acceptable Values.
Drying
of Transformer
Short
circuit heating and hot air circulation.
Oil
Definition
of terms used in oil characteristic; acceptable values for BDV, tan d,
specific resistance, neutralisation value, interfacial tension, gas content,
oil filtration techniques - Fuller's earth, Enervac and Velcon system; DGA
(Dissolved Gas Analysis), Principle, Roger's method, Limiting value of
Hydrocarbon concentrations, Case studies, Condition monitoring, recommended
test and periodicity.
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