High-Frequency Transformer and Reactor Models for Network Studies - Part A: White-Box Models

Summary

Part A – White-box models

The reliable and safe operation of the transformer requires that the dielectric stresses imposed by transient overvoltages are kept within acceptable limits. White-box models are detailed models of the transformer which permit to calculate the internal voltages in the transformer. Such models are used by the transformer manufacturers to ensure that the transformer will withstand the standard lightning impulse voltage test.  CIGRE JWG A2/C4.52 has reviewed the various white-box models with consideration to parameter determination, accuracy, and possible inclusion in electromagnetic transient simulation programs for use in general transient studies. The daily-use models by manufacturers are normally lumped-parameter type models whose parameters are calculated by analytical formulae. The most common calculation procedures and model formulations are reviewed by the JWG. Comparison with measurements shows that the models can give substantial errors in the transient waveforms, although the maximum internal stresses are well represented. The accuracy is improved by introduction of empirical damping factors, while the most accurate result is achieved when calculating the model's parameters using the finite element method, with the branch impedance matrix represented by a rational model that is calculated from discrete frequency samples. The manufacturers may be reluctant to sharing their models. This TB is one of five TBs from the JWG.

Additional informations

Authors

Bjørn Gustavsen, Convenor (NO), Angelica Rocha, Secretary (BR),

Alvaro Portillo (UY), Andrzej Holdyk (NO), Anniyappan Palani (DE), Baudilio Valecillos (CH), Behzad Kordi (CA), Bogdan Andriienko (UA), Carlos González-García (ES), Casimiro Álvarez-Mariño (ES), Daniil Matveev (RU), Davor Vujatovic (UK), Ebrahim Rahimpour (DE), Enrique Mombello (AR), Esteban Portales (CA), Federico Portillo (UY), Guillermo Andrés Díaz Flórez (CO), Gustavo H. C. Oliveira (BR), Hans De Herdt (BE), Hans Kristian Høidalen (NO), Ji-Hong Kim (KR), Jos Veens (NL), Jose Carlos Mendes (BR), José Francisco Lofrano (BR), Juliano Montanha (BR), Luiz Fernando de Oliveira (BR), Marc-Olivier Roux (CA), Maxym Ostrenko (UA), Michel Rioual (FR), Mikhail Frolov (RU), Oliver Sterz (DE), Ricardo Castro Lopes (PT), Robert Degeneff (US), Rodrigo Ronchi (MX), Rogerio Azevedo (BR), Shikin Jamil (UK), Tobias Röhrl (DE), Triomphant Ngnegueu (FR), Xosé López-Fernández (ES)

Keywords

power transformers, reactors, power systems, technical performance

Other parts

• High-Frequency Transformer and Reactor Models for Network Studies - Part D: Model interfacing and specifications
• High-Frequency Transformer and Reactor Models for Network Studies - Part B: Black-Box Models
• High-Frequency Transformer and Reactor Models for Network Studies - Part C: Grey Box Models
• High-Frequency Transformer and Reactor Models for Network Studies - Part E: Measurements and transformer design details