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

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…