High-Frequency Transformer and Reactor Models for Network Studies - Part C: Grey Box Models

Summary

Part C – Grey-box models

The reliable and safe operation of the transformer requires that the dielectric stresses imposed by transient overvoltages are kept within acceptable limits. Grey-box models of transformers can be either simplified models or ladder-type detailed models. CIGRE JWG A2/C4.52 has reviewed alternative grey-box models with consideration to parameter determination, accuracy and to the inclusion of such models in electromagnetic transient (EMT) simulation programs for use in general transient studies. The simplified models can range from a single capacitor to 50 Hz standard models with added capacitances. Alternative variants are analyzed and compared against transformer measurements for accuracy validation. Models that are obtained from test report data alone tend to have too low attenuation. Usage of damping factors can improve the accuracy. The capacitance values that are to be used in the models can come from the test report, but they need to be modified to account for the series capacitance and winding connections. The frequency range of the simplified models is limited upwards to the transformer's first resonance peak. The resulting models are straightforward to apply in EMT simulation programs. Modeling by a detailed, fitted ladder network is still an area of research and needs more exploration. 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 A: White-Box Models
• 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 E: Measurements and transformer design details