Frequency Response Analysis (FRA) in the Service of Reliability Analysis of Power Transformers
2011 (English)Conference paper (Refereed)
This paper aims to improve condition monitoring of power transformers by concerning thermal modeling. The common loss of life estimate could be used as a condition estimate during condition monitoring but for this estimate to be reliable, an accurate thermal model for the hotspot temperature calculations is absolutely essential to develop.
Studies have shown a significant deviation between measured and calculated hotspot values. This deviation is particularly pronounced during transient load at severe environments. Temperature modeling during transient load conditions puts high requirements on the dynamic part of the model; hence focus has been given to this particular load type in this paper. Moreover, the Nordic climate have winters with temperatures as low as -20C. In order to apply these models in these settings, this paper is discussing this as well. As possible thermal model improvements, this paper identifies the ambient temperature, loss variation with temperature, and oil viscosity changes with temperature as features which need to be utilized in the thermal model. This paper describes the current research within these areas.
Furthermore, presented in a concluding discussion, the appropriate approach for these models are seen to be either the thermal-electrical analogy or the soft modeling techniques.
Place, publisher, year, edition, pages
FRA, Transformer diagnostic, reliability analysis, degradation modelling
Electrical Engineering, Electronic Engineering, Information Engineering
IdentifiersURN: urn:nbn:se:kth:diva-129984OAI: oai:DiVA.org:kth-129984DiVA: diva2:654018
QC 201310072013-10-072013-10-072013-10-07Bibliographically approved