Independent thesis Advanced level (professional degree), 20 credits / 30 HE credits
A major transformer failure is important to avoid both economically
and for the reliability of the power supply. Much can be won if
potential failures are detected in an early stage and preventive
measures can be taken. Condition monitoring is a process and
technique that focus on significant parameters with the potential to
indicate a failure under development.
Opportunities, benefits and possible drawbacks of using the method
with transformer fundamental quantities, TFQ, has been studied in
this thesis. Focus is on three basic transformer fundamental
quantities monitored; turn ratio, short-circuit impedance and power
loss. TFQ has been compared to conventional methods used today by
Vattenfall for condition monitoring of power transformers.
The business case possibilities for Vattenfall to use TFQ as input
for transformer diagnostics compared to conventional methods used
today has been estimated. The result is that condition monitoring
based on DGA (dissolved gas analysis), is more suited for Vattenfall
in the current situation. TFQ is more on a conceptual level than a
The thesis has been carried out at Vattenfall Research and
Development, division of Power Technology, in Solna.