Case Study 1: Converter Transformer Load Losses

Locally the LV-winding had very high losses, causing conductors to overheat with consequent turn to turn failure. Because of the small amount of cellulose being degraded, the Dissolved Gas Analyses (DGA) may not alert the end user about the imminent failure. [more...]

Case Study 2: GSU Transformer Upgrade – Tank Hot Spot

Significant localized tank cover flange heating had been observed by infrared scan on a 185 MVA GSU transformer, compromising the aimed upgrading (by 23%) of the name plate MVA rating. The enhanced oil cooling could not cope with the localized tank hot spot. [more...]

Case Study 3: Forces Under Double Inrush Condition

Axial forces on HV winding under inrush condition need to be evaluated taking into account residual core magnetisation and the presence of a rectifier transformer connected to the MV. The regulating transformer has to face double inrush currents (its own and the one of the rectifier transformer). [more...]

Case Study 4: Top Lead Exit Thermal Analysis

Lead exits in copper with or without slits have been simulated in order to determine the best design from a thermal point of view. [more...]

Case Study 5: LV Losses

Very high load losses in the LV winding have been observed. The LV winding was built following the “classical” design rules for the transposition of conductors in parallel. However, only simulations can verify the validity of the “classical solution” for each specific design. [more...]

Case Study 6: Tank Temperature Rise Verification

The coupled magnetic–thermal simulation of a rectifier transformer has been performed. The presence of a complex LV busbars system makes the localization of the hot spots not trivial. [more...]